Search

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To screen eminent litchi varieties suitable for the development of natural antioxidant products, the total phenol, total proanthocyanidin, total flavonoid contents and A-type oligomeric procyanidin fractions in the pericarps of seven diverse litchi cultivars were analyzed. The in vitro antioxidant activities including DPPH, ABTS+ free radical scavenging and FRAP were determined. The results demonstrated that the total phenols, total proanthocyanidins, total flavonoids as well as total A-type oligomeric procyanidins contained in the pericarp extract of 'Hemaoli' were the highest. In addition, the primary and secondary mass spectra of the contained substances were analyzed and identified by electrospray liquid-mass spectrometry with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS). The mass spectrometry results demonstrated that the oligomeric procyanidin fractions contained in litchi pericarps were mainly epicatechin, procyanidin A2, procyanidin A4, A-type trimer and tetramer. Moreover, the content of A-type oligomeric procyanidins in litchi pericarp varied significantly (P<0.05) among diverse cultivars. The pericarp extract of 'Hemaoli' possessed potent free radical scavenging activity (DPPH: 1144.60 μmol Trolox/g DW, ABTS+: 2905.56 μmol Trolox/g DW, FRAP: 868.84 μmol Trolox/g DW). The contents of A-type procyanidin monomer, dimer and trimer were significantly correlated with antioxidant activity by Pearson's correlation analysis (P<0.05). In summary, a comprehensive analysis indicated that the pericarp extract of 'Hemaoli' contained the highest content of A-type oligomeric procyanidins as well as remarkable antioxidant activity compared to other cultivars. Therefore, 'Hemaoli' could be utilized as a novel potential material for the development of natural antioxidant products. [ABSTRACT FROM AUTHOR]

To screen eminent litchi varieties suitable for the development of natural antioxidant products, the total phenol, total proanthocyanidin, total flavonoid contents and A-type oligomeric procyanidin fractions in the pericarps of seven diverse litchi cultivars were analyzed. The in vitro antioxidant activities including DPPH, ABTS+ free radical scavenging and FRAP were determined. The results demonstrated that the total phenols, total proanthocyanidins, total flavonoids as well as total A-type oligomeric procyanidins contained in the pericarp extract of 'Hemaoli' were the highest. In addition, the primary and secondary mass spectra of the contained substances were analyzed and identified by electrospray liquid-mass spectrometry with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS). The mass spectrometry results demonstrated that the oligomeric procyanidin fractions contained in litchi pericarps were mainly epicatechin, procyanidin A2, procyanidin A4, A-type trimer and tetramer. Moreover, the content of A-type oligomeric procyanidins in litchi pericarp varied significantly (P

Abstract Bio-transformations refer to the chemical modifications made by an organism on a chemical compound that often involves the interaction of plants with microbes to alter the chemical composition of soil or plant. Integrating bio-transformations and entomopathogenic fungi into litchi cultivation can enhance symbiotic relationships, microbial enzymatic activity in rhizosphere, disease suppression and promote overall plant health. The integration of biological formulations and entomopathogenic fungi can significantly influence growth, nutrient dynamics, physiology, and rhizosphere microbiome of air-layered litchi (Litchi chinensis Sonn.) saplings. Biological modifications included, K-mobilizers, AM fungi, Pseudomonas florescence and Azotobacter chroococcum along with Metarhizium, entomopathogenic fungi have been used. The treatments included, T1-Litchi orchard soil + sand (1:1); T2-Sand + AM fungi + Azotobacter chroococcum (1:2:1); T3-Sand + Pseudomonas florecence + K-mobilizer (1:1:1); T4- AM fungi + K-mobilizers (1:1); T5, P. Florecence + A. chroococcum + K-mobilizer (1:1:1); T6-Sand + P. florecence (1:2) and T7-Uninoculated control for field performance. Treatments T4-T6 were further uniformly amended with drenching of Metarrhizium in rhizosphere. T2 application significantly increased resident microbe survival, total chlorophyll content and root soil ratio in seedlings. A. chroococcum, Pseudomonas, K-mobilizers and AM fungi increased in microbial biomass of 2.59, 3.39, 2.42 and 2.77 times, respectively. Acidic phosphatases, dehydrogenases and alkaline phosphatases were increased in rhizosphere. Leaf nutrients reflected through DOP were considerably altered by T2 treatment. Based on Eigen value, PCA-induced changes at biological modifications showed maximum total variance. The study inferred that the bio-transformations through microbial inoculants and entomopathogenic fungi could be an encouraging strategy to enhance the growth of plants, health and productivity. Such practices align well with the goals of sustainable agriculture through biological means by reducing dependency on chemical inputs. By delving into these aspects, the research gaps including microbial processes, competitive and symbiotic relationships, resistance in microbes and how complex interactions among bio-transformations, entomopathogenic fungi and microbes can significantly impact the health and productivity of litchi. Understanding and harnessing these interactions can lead to more effective and sustainable farming practices.

Certain litchi varieties, such as “Nuomici”, are highly susceptible to preharvest fruit drop, which leads to significant losses in fruit yield and economic value. However, the precise molecular mechanisms underlying this issue are not yet fully understood. In this study, we aimed to elucidate the signaling pathways that facilitate preharvest fruit drop in litchi, using “Nuomici” and “Huaizhi” cultivars as examples, which demonstrate high and low preharvest fruit drop rates, respectively. Our findings revealed that “Nuomici” experienced a substantial preharvest fruit drop, with a cumulative rate of 41.68%, significantly higher than the 1.44% observed in “Huaizhi”. Cellulase activity assays showed a significant increase in cellulase activity in the abscission zone of “Nuomici”, which coincided with the occurrence of preharvest fruit drop, in contrast to the relatively low levels in “Huaizhi”. Phytohormone assays indicated lower indole-3-acetic acid content in the pericarp, aril, and seeds of “Nuomici” during the preharvest stage compared to “Huaizhi”, coupled with higher abscisic acid levels in the seeds of “Nuomici”. Furthermore, transcriptomic analysis identified 180, 282, 655, and 241 differentially expressed genes (DEGs) in the pericarp, aril, seed, and abscission zone, respectively, between the two cultivars during preharvest fruit drop. These DEGs are intricately involved in the generation and transmission of abscission signals from fruit tissues, encompassing PIN, PIN-LIKES, LAX, and SAUR genes related to polar auxin transport, ethylene diffusion, as well as perceiving these signals and activating the abscission process within the abscission zone. This includes ACO and ILR genes involved in hormone biosynthesis and signal transduction, regulation by WRKY, NAC, and bHLH transcription factors, AAO genes involved in response to reactive oxygen species, and EXP, EG, and PG genes involved in cell wall degradation in the abscission zone. Based on these comprehensive findings, we propose a model for preharvest fruit drop triggered by a series of molecular events in litchi, providing valuable insights into the complex mechanisms governing this phenomenon.

Flower color variations have increasingly been recognized as playing an important role in the adaptation to UV-B radiation; however, the underlying mechanism is poorly understood in perennial fruit trees. Litchi is an important fruit tree, and extremely early maturing (EEM) and middle-to-late-maturing (MLM) cultivars that originated from regions with high and low UV-B radiation have dark brown and light yellow flower buds, respectively, while their hybrid early-maturing (EM) cultivars have an intermediate brown flower bud. This study comprehensively analyzed the metabolome and transcriptome of flower buds of litchi EEM, EM and MLM cultivars to explore the mechanism underlying flower color variation during the adaptation to UV-B radiation for the first time. Metabolomic analysis identified 72 flavonoids in litchi flower buds, among which a higher accumulation of flavonol glycosides was responsible for darker flower buds of EEM cultivars. And transcriptome analysis revealed key structural genes, including LcCHI, LcFLS and seven UGTs, together with two transcription factors (LcMYB12 and LcMYB111), which could be directly up-regulated by UV-B radiation, playing critical roles in regulating the differential accumulation of flavonol glycosides. These results provide new insights into the molecular mechanism underlying adaptation to UV-B radiation and provide a genetic basis for future breeding of stress-tolerant cultivars of litchi. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis Sonn.) is a type of commercially prevalent subtropical and tropical fruit. Since litchi has a highly heterozygous genetic background and a long reproductive cycle, conventional breeding methods (such as hybridization) have limited ability to nurture new litchi cultivars. Here, an efficient and stable Agrobacterium tumefaciens-mediated genetic transformation of embryogenic callus was established in ‘Feizixiao’ litchi. Transgenic materials were verified using polymerase chain reaction (PCR) analysis, β-glucuronidase (GUS) assay, and green fluorescent protein (GFP) assay. To implement the technology of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) technology in ‘Feizixiao’ litchi and verify the validity of these transformation systems, the litchi polyphenol oxidase gene (LcPPO, JF926153) was knocked out. Various categories of mutations, covering base insertions, deletions, and substitutions, were found in transgenic materials via sequence analysis. The transformation system achieved high feasibility and efficiency, and the system of CRISPR/Cas9 was successfully employed to edit genes in ‘Feizixiao’ litchi. This work provides an essential foundation for investigating the functions of genes and accelerating litchi genetic improvement.

Flower color variations have increasingly been recognized as playing an important role in the adaptation to UV-B radiation; however, the underlying mechanism is poorly understood in perennial fruit trees. Litchi is an important fruit tree, and extremely early maturing (EEM) and middle-to-late-maturing (MLM) cultivars that originated from regions with high and low UV-B radiation have dark brown and light yellow flower buds, respectively, while their hybrid early-maturing (EM) cultivars have an intermediate brown flower bud. This study comprehensively analyzed the metabolome and transcriptome of flower buds of litchi EEM, EM and MLM cultivars to explore the mechanism underlying flower color variation during the adaptation to UV-B radiation for the first time. Metabolomic analysis identified 72 flavonoids in litchi flower buds, among which a higher accumulation of flavonol glycosides was responsible for darker flower buds of EEM cultivars. And transcriptome analysis revealed key structural genes, including LcCHI, LcFLS and seven UGTs, together with two transcription factors (LcMYB12 and LcMYB111), which could be directly up-regulated by UV-B radiation, playing critical roles in regulating the differential accumulation of flavonol glycosides. These results provide new insights into the molecular mechanism underlying adaptation to UV-B radiation and provide a genetic basis for future breeding of stress-tolerant cultivars of litchi.

Real-time reverse transcription quantitative PCR (RT-qPCR) is an important tool for gene expression analysis. Suitable reference genes are the basis of accurate and reliable RT-qPCR results. Litchi (Litchi chinensis Sonn.) is a commercially important tropical and subtropical fruit, but rapid pericarp browning is a substantial negative impact on its commercial use. Reference gene validation could help in the screening for genes involved in the browning mechanism. We assessed 15 new candidate reference genes from litchi transcriptome to determine stable reference genes for RT-qPCR analysis of pericarps from different cultivars, with differing postharvest storage, and under pathogenic stress. Ct values, geNorm, Normfinder, and RefFinder algorithms, were used to identify genes with the most stable transcription. GAGA-25 was the gene with the most stable transcription for comparing different varieties of the fresh pericarp. HDAC9 was the gene with the most stable transcription for postharvest pericarp. STAM was the gene with the most stable transcription for inoculated pericarp. Of the candidate reference genes, GAGA-25 was the most stable reference gene across the complete sample set. This study evaluated reference gene stability for RT-qPCR in litchi pericarp. This work provides a foundation for using qPCR to study gene function and molecular mechanism studies of litchi pericarp browning. [ABSTRACT FROM AUTHOR]

Real-time reverse transcription quantitative PCR (RT-qPCR) is an important tool for gene expression analysis. Suitable reference genes are the basis of accurate and reliable RT-qPCR results. Litchi (Litchi chinensis Sonn.) is a commercially important tropical and subtropical fruit, but rapid pericarp browning is a substantial negative impact on its commercial use. Reference gene validation could help in the screening for genes involved in the browning mechanism. We assessed 15 new candidate reference genes from litchi transcriptome to determine stable reference genes for RT-qPCR analysis of pericarps from different cultivars, with differing postharvest storage, and under pathogenic stress. Ct values, geNorm, Normfinder, and RefFinder algorithms, were used to identify genes with the most stable transcription. GAGA-25 was the gene with the most stable transcription for comparing different varieties of the fresh pericarp. HDAC9 was the gene with the most stable transcription for postharvest pericarp. STAM was the gene with the most stable transcription for inoculated pericarp. Of the candidate reference genes, GAGA-25 was the most stable reference gene across the complete sample set. This study evaluated reference gene stability for RT-qPCR in litchi pericarp. This work provides a foundation for using qPCR to study gene function and molecular mechanism studies of litchi pericarp browning.

Energy status of cells is a key factor in switching on the senescence process of horticultural crops. Extracellular ATP (eATP) and its receptor DORN1 play pivotal roles in responding to energy deficit signals and are involved in multiple biological processes, yet their mechanisms remain unclear. A total of 17 LcDORN1 genes were identified in the genome of litchi. During storage of litchi fruit, eATP gradually acummulated with the upregulated expression of LcDORN1s. However, this trend was delayed by the application of exogenous ATP, ultimately leading to delayed senescence of the litchi fruit. LcDORN1.2 and LcDORN1.6, which were verified to be localized in the endoplasmic reticulum, were specifically targeted and modulated by LcmiR3627f and LcmiR159b , respectively. The expression of LcPLD was upregulated, whereas the expression of LcAPY1 was downregulated in LcDORN1.6 silenced litchi fruit. This research provides novel insights into the roles of eATP and its receptor, LcDORN1s, in the ripening and senescence of litchi fruit. • Totally 17 LcDORN1s were identified as eATP receptor genes in litchi genome. • LcDORN1 negetively regulates energy homeostasis and litchi senescence. • LcDORN1.2 and LcDORN1.6 were seperately targeted by LcmiR3627f and LcmiR159b. • LcDORN1.2 and LcDORN1.6 were localized in the endoplasmic reticulum. [ABSTRACT FROM AUTHOR]

Aroma is considered a fundamental component of fruit flavor. Variations in the composition and content of volatile organic compounds (VOCs) contribute to noticeable differences in fruit aromas. Litchi is a delicious tropical and subtropical fruit, and a large number of germplasm resources with unique aromas have emerged during the past 2000 years of cultivation. In this review, our aim is to collect, compare, integrate, and summarize the available literature on the profiles of VOCs of 25 litchi cultivars. We showed that a total of 556 VOCs were reported from litchi fruit, and the aroma of litchi is mainly determined from the content and composition of monoterpenoids and alcohols, including linalool, geraniol, limonene, terpinolene, β-citronellol, p-cymene, nerol, α-terpineol, cis-rose oxide, β-myrcene, 4-terpineol, citral, and neral (cis-citral), which might contribute to the rose-like or citrus-like aroma of litchi fruit. Moreover, sulfur-containing volatile compounds (VSCs) possibly impart a special flavor to litchi fruit. This review would be a valuable resource for researchers aiming to improve litchi aroma quality by elucidating the possible mechanisms underlying VOC biosynthesis and their metabolism in litchi fruit. [ABSTRACT FROM AUTHOR]

Cancer metabolism has emerged as a potential target for innovative therapeutic approaches in the treatment of cancer. Cancer metabolism has received much attention, particularly in relation to glucose metabolism. It has been observed that human malignancies have high levels of glucose-6-phosphate dehydrogenase (G6PD) activity which is an important enzyme of glucose metabolism. This overactivity is associated with the cell death and angiogenesis, highlighting its potential as a viable target for cancer treatment. This study was conducted to examine the methanolic extracts from the seeds, bark and leaves of litchi (Litchi chinensis Sonn.) in order to discover effective compounds targeting G6PD and potentially active entities against liver cancer. Plant extract screening for the target protein was carried out through enzymatic activity assay. The recombinant plasmid pET-24a-HmG6PD was expressed in E. coli (BL21-DE3) strain, then purified and assessed using metal affinity chromatography with Ni-NTA columns and SDS-PAGE. The cytotoxicity of plant extracts against liver cancer HepG2 cells was assessed using the MTT assay. All three extracts demonstrated significant inhibitory effects (>80% inhibition) against G6PD. They were then subjected to testing at various concentrations, and their IC 50 values were subsequently determined. The extracts of litchi (leaf, IC 50 : 1.199 μg/mL; bark, IC 50 : 2.350 μg/mL; seeds, IC 50 : 1.238 μg/mL) displayed significant inhibition of G6PD activity at lower concentrations. Subsequently, the leaf extract of litchi was further assessed for its impact on HepG2 cell lines in a dose-dependent manner and exhibited strong potential as an inhibitor of cancer cell progression. Moreover, the results of acute toxicity study in mice revealed nontoxic effects of litchi leaf extract on hepatocytes. The results imply that Litchi chinensis leaf extract could be considered as a promising candidate for safer drug development in the treatment of liver cancer. [Display omitted] • Cancer metabolism has received much attention, particularly in relation to glucose metabolism. • A key enzyme of glucose metabolism is G6PD, that is linked with the malignancy, making it a viable target for cancer therapy. • The methanolic extracts of Litchi chinensis showed significant inhibition of G6PD activity at lower concentrations. • The leaf extract of Litchi chinensis exhibited significant inhibitory potential against HepG2 cell progression. • Methanolic extracts of Litchi chinensis could be promising candidates for safer drug development for liver cancer therapy. [ABSTRACT FROM AUTHOR]

Real-time reverse transcription quantitative PCR (RT-qPCR) is an important tool for gene expression analysis. Suitable reference genes are the basis of accurate and reliable RT-qPCR results. Litchi (Litchi chinensis Sonn.) is a commercially important tropical and subtropical fruit, but rapid pericarp browning is a substantial negative impact on its commercial use. Reference gene validation could help in the screening for genes involved in the browning mechanism. We assessed 15 new candidate reference genes from litchi transcriptome to determine stable reference genes for RT-qPCR analysis of pericarps from different cultivars, with differing postharvest storage, and under pathogenic stress. Ct values, geNorm, Normfinder, and RefFinder algorithms, were used to identify genes with the most stable transcription. GAGA-25 was the gene with the most stable transcription for comparing different varieties of the fresh pericarp. HDAC9 was the gene with the most stable transcription for postharvest pericarp. STAM was the gene with the most stable transcription for inoculated pericarp. Of the candidate reference genes, GAGA-25 was the most stable reference gene across the complete sample set. This study evaluated reference gene stability for RT-qPCR in litchi pericarp. This work provides a foundation for using qPCR to study gene function and molecular mechanism studies of litchi pericarp browning. [ABSTRACT FROM AUTHOR]

Aroma is considered a fundamental component of fruit flavor. Variations in the composition and content of volatile organic compounds (VOCs) contribute to noticeable differences in fruit aromas. Litchi is a delicious tropical and subtropical fruit, and a large number of germplasm resources with unique aromas have emerged during the past 2000 years of cultivation. In this review, our aim is to collect, compare, integrate, and summarize the available literature on the profiles of VOCs of 25 litchi cultivars. We showed that a total of 556 VOCs were reported from litchi fruit, and the aroma of litchi is mainly determined from the content and composition of monoterpenoids and alcohols, including linalool, geraniol, limonene, terpinolene, β-citronellol, p-cymene, nerol, α-terpineol, cis-rose oxide, β-myrcene, 4-terpineol, citral, and neral (cis-citral), which might contribute to the rose-like or citrus-like aroma of litchi fruit. Moreover, sulfur-containing volatile compounds (VSCs) possibly impart a special flavor to litchi fruit. This review would be a valuable resource for researchers aiming to improve litchi aroma quality by elucidating the possible mechanisms underlying VOC biosynthesis and their metabolism in litchi fruit.

• Field observation embodying that Litchi chinensis Sonn. cv. 'Huaizhi' as rootstock did show a wide compatibility. • Nutrients contents, mineral nutrition (N and P) levels, and antioxidant enzyme activities, might be related to the wide compatibility of Huaizhi as rootstock. • Microscopic observation showed a compatible healing dynamics. • DEGs related to phenylpropanoid biosynthesis, plant hormone biosynthesis and signal transduction, sucrose and starch metabolism, MAPK signaling pathway might be involved in the wide compatibility of 'Huaizhi' as rootstock. Litchi chinensis Sonn. cv. 'Huaizhi' (HZ) is an ancient cultivar of litchi. It has been used as widely compatible rootstock for litchi grafting for a long time. However, the mechanism of HZ as widely compatible rootstock is still unclear. In the present study, physiology, morphological anatomy, as well as transcriptomics were conducted to reveal the reasons for HZ with wide compatibility in litchi grafting. Field observation were conducted on the grafting combinations of HZ/HZ (homografting as the control), FZX/HZ and MGL/HZ (the scion with good grafting compatibility in production), SYH/HZ, HHDHL/HZ and WHL/HZ (the scion with weak grafting compatibility in production), embodying that HZ as rootstock did show a wide compatibility. The physiological and biochemical indicators of scion new shoot leaves and scion mother tree indicated that nutrients contents (dry matter weight, total soluble sugar, and starch), mineral nutrition (N and P) levels, and antioxidant enzyme (superoxide dismutase and peroxidase) activities, might be related to the wide compatibility of HZ as rootstock. Microscopic observation of the paraffin sections of healing sites at different stages showed that the necrotic layer of three representative litchi grafting combinations of HZ/HZ, WHL/HZ and MGL/HZ basically disappeared from 14 d to 21 d after grafting, and the callus differentiated into a large number of protoxylem cells, indicating a compatible healing dynamics. Subsequently, a total of 14,384 differentially expressed genes (DEGs) were identified by RNA-seq, of which 2,831 DEGs exhibited the same expression trend within three grafting combinations, enriching into phenylpropanoid biosynthesis, plant hormone biosynthesis and signal transduction, sucrose and starch metabolism, MAPK signaling pathway, peroxisome and other metabolic pathways. These results provide a theoretical basis for the adjustment of cultivar structure in litchi production. [ABSTRACT FROM AUTHOR]

Objetivou-se avaliar a influência da radiação (UV-C) na conservação de lichias da cv. ‘Bengal’ frigoarmazenadas. Os frutos foram submetidos a exposição da luz ultravioleta em equipamento IRINOX (UV-C com λ=254 nm), acondicionados em bandeja de poliestireno expandido sem recobrimento e armazenados em câmara fria (5±0,5 ºC e 90±5 % de UR) por quinze dias. As análises foram realizadas a cada três dias e avaliados: perda de massa, atividade respiratória, pH, sólidos solúveis, acidez titulável, índice de maturação e ácido ascórbico. O experimento foi conduzido em delineamento inteiramente casualizado, em esquema fatorial e os dados foram submetidos à análise de variância e regressão polinomial (p

The study aimed to investigate the nephroprotective and cardioprotective effects of ethanol extract of litchi leaf (LI) in two-kidney-one-clip (2K1C) rat model. HPLC analysis revealed the presence of several polyphenolic antioxidants in LI. Correspondingly, LI at 50–200 mg/kg reduced the level of oxidative stress markers (MDA, APOP, NO) and improved level of endogenous antioxidant enzymes (CAT, SOD) in 2K1C rats. Besides, LI caused significant improvements in kidney and heart functions in 2K1C rats by reducing the plasma level of uric acid and creatinine as well as CK-MB. Consistent with the biochemical findings, histopathological data further confirmed that LI is effective in decreasing heart and kidney injuries, oxidative stress and inflammation which ensued in 2K1C rats. Collectively, the outcomes suggest that the LI enriched in polyphenolic antioxidants may provide the protection against excessive oxidative stress, inflammation and tissue injury, thereby improving the kidney and heart function in 2K1C rats.

The aim of this study was to investigate the effects of three different drying methods, freeze drying (FD), vacuum drying (VD) and oven drying (OD) on phenolic contents and antioxidant activities of litchi fruits. 20 polyphenols were exactly identified in the litchi fruits by UPLC-QqQ/MS. Significant losses were observed in the contents of total polyphenols and antioxidant activities in the dried litchi when compared with the fresh litchi. Principle component analysis indicated that there was significant difference of phenolic component between the use of thermal drying (VD and OD) and FD. Our results suggest that FD is the optimum drying method for litchi fruits considering the content of total polyphenols and antioxidant activities. [ABSTRACT FROM AUTHOR]

• Exogenous cytokinin treatment, applied during litchi pericarp cell division, result in mature fruit with thicker pericarp, reduced rate of post-harvest water loss and reduced susceptibility to post-harvest pericarp browning. • Cytokinin application prior to the onset of litchi fruit maturation inhibits fruit pericarp color change, but does not postpone aril maturation as implies from the rate of sugar accumulation and acid degradation. • During litchi fruit development, the timing of cytokinin application induce cell-type specific proliferation leading to differential effect on fruit pericarp anatomy. Litchi (Litchi chinensis Sonn.) is a subtropical fruit known for its attractive red pericarp color, semi-translucent white aril and unique flavor and aroma. Rapid post-harvest pericarp browning strictly limits litchi fruit marketing. In the current research, we hypothesized that modification of litchi fruit pericarp anatomy by hormone application may reduce fruit susceptibility to post-harvest pericarp browning. In this context, we hypothesized that cytokinin treatment, known to induce cell division, may yield fruit with thicker pericarp and reduced susceptibility for fruit surface micro-crack formation, water loss and post-harvest pericarp browning. Exogenous cytokinin treatment was applied at different stages along the course of litchi fruit development and the effect on fruit pericarp anatomy, fruit maturation and postharvest pericarp browning was investigated. Interestingly, cytokinin treatment, applied 4 weeks after full female bloom (WFB), during the phase of pericarp cell division, led to mature fruit with thicker pericarp, reduced rate of post-harvest water loss and reduced susceptibility to post-harvest pericarp browning, as compared to non-treated control fruit. Histological sections ascribe the difference in pericarp anatomy to increased cell proliferation in the parenchymatic tissue and the highly-lignified brachysclereid cell layer. In contrast, exogenous cytokinin treatment applied 7 WFB, following the phase of pericarp cell division, significantly increased epidermal-cell proliferation but had no significant effect on overall fruit pericarp thickness and only minor affect on post-harvest water loss or pericarp browning. Interestingly, the late cytokinin treatment also significantly postponed fruit maturation-associated anthocyanin accumulation and chlorophyll degradation, as previously reported, but had no effect on other parameters of fruit maturation, like total soluble sugars and total titratable acids typically modified during aril maturation. In conclusion, exogenous cytokinin treatment at different stages in fruit development differentially modifies litchi fruit pericarp anatomy by induction of cell-type specific cell proliferation. Early cytokinin treatment during the phase of pericarp cell division may prolong litchi fruit storage by reducing fruit susceptibility to post-harvest water loss and pericarp browning. [ABSTRACT FROM AUTHOR]

The residual sulfite caused by sulfur fumigation (SF) is a hazard to health and influenced the export trade of litchi. Desulfurization (DS) is a valid chemical method to reduce the residual sulfite. However, the effect of DS on fumigated litchi has not been studied at physiological and molecular level. This study was aimed to evaluate the effect of DS (SF plus 3% desulfurizer) on the postharvest quality, sulfite residue, and the sulfite metabolism in sulfitated "Feizixiao" litchi during the 4°C storage. Results indicated that the DS promoted the color recovery of sulfitated litchi and achieved an effect similar to SF on controlling rot and browning. DS recovered the water content and respiration rate of sulfitated litchi pericarp. Thus, DS improves commodity properties of sulfitated litchi. Moreover, DS greatly reduced sulfite residue especially in pulp and ensured the edible safety of sulfitated litchi. The activities of sulfite oxidase, sulfite reductase, serine acetyltransferase, and O‐acetylserine(thiol) lyase in pulp increased after SF but fell down after DS while the expressions of their encoding genes decreased after SF but then rallied after DS. These results indicated the key role of these enzymes in sulfite metabolism after SF and DS changed the sulfite metabolism at both enzymatic and transcriptional level. It could be concluded that DS used in this study was an effective method for improving the color recovery and ensuring the edible safety of sulfitated litchi by not only chemical reaction but also both of enzymatic and transcriptional regulation. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis) is an important subtropical fruit tree with high commercial value. However, the short and centralized fruit maturation period of litchi cultivars represents a bottleneck for litchi production. Therefore, the development of novel cultivars with extremely early fruit maturation period is critical. Previously, we showed that the genotypes of extremely early-maturing (EEM), early-maturing (EM), and middle-to-late-maturing (MLM) cultivars at a specific locus SNP51 (substitution type C/T) were consistent with their respective genetic background at the whole-genome level; a homozygous C/C genotype at SNP51 systematically differentiated EEM cultivars from others. The litchi gene on which SNP51 was located was annotated as flavonol synthase (FLS), which catalyzes the formation of flavonols. Here, we further elucidate the variation of the FLS gene from L. chinensis (LcFLS) among EEM, EM, and MLM cultivars. EEM cultivars with a homozygous C/C genotype at SNP51 all contained the same 2,199-bp sequence of the LcFLS gene. For MLM cultivars with a homozygous T/T genotype at SNP51, the sequence lengths of the LcFLS gene were 2,202–2,222 bp. EM cultivars with heterozygous C/T genotypes at SNP51 contained two different alleles of the LcFLS gene: a 2,199-bp sequence identical to that in EEM cultivars and a 2,205-bp sequence identical to that in MLM cultivar ‘Heiye.’ Moreover, the coding regions of LcFLS genes of other MLM cultivars were almost identical to that of ‘Heiye.’ Therefore, the LcFLS gene coding region may be used as a source of diagnostic SNP markers to discriminate or identify genotypes with the EEM trait. The expression pattern of the LcFLS gene and accumulation pattern of flavonol from EEM, EM, and MLM cultivars were analyzed and compared using quantitative real-time PCR (qRT-PCR) and high-performance liquid chromatography (HPLC) for mature leaves, flower buds, and fruits, 15, 30, 45, and 60 days after anthesis. Flavonol content and LcFLS gene expression levels were positively correlated in all three cultivars: both decreased from the EEM to MLM cultivars, with moderate levels in the EM cultivars. LcFLS gene function could be further analyzed to elucidate its correlation with phenotype variation among litchi cultivars with different fruit maturation periods.

Sucrose phosphate synthase (SPS, EC 2.4.1.14) is a key enzyme that regulates sucrose biosynthesis in plants. SPS is encoded by different gene families which display differential expression patterns and functional divergence. Genome-wide identification and expression analyses of SPS gene families have been performed in Arabidopsis, rice, and sugarcane, but a comprehensive analysis of the SPS gene family in Litchi chinensis Sonn. has not yet been reported. In the current study, four SPS gene (LcSPS1, LcSPS2, LcSPS3, and LcSPS4) were isolated from litchi. The genomic organization analysis indicated the four litchi SPS genes have very similar exon-intron structures. Phylogenetic tree showed LcSPS1-4 were grouped into different SPS families (LcSPS1 and LcSPS2 in A family, LcSPS3 in B family, and LcSPS4 in C family). LcSPS1 and LcSPS4 were strongly expressed in the flowers, while LcSPS3 most expressed in mature leaves. RT-qPCR results showed that LcSPS genes expressed differentially during aril development between cultivars with different hexose/sucrose ratios. A higher level of expression of LcSPS genes was detected in Wuheli, which accumulates higher sucrose in the aril at mature. The tissue- and developmental stage-specific expression of LcSPS1-4 genes uncovered in this study increase our understanding of the important roles played by these genes in litchi fruits.

The aim of the study was to assess the influence of season and different substrates on rooting of air layers of lychee (Litchi chinensisSonn.) for the production of seedlings to ensure the formation of uniform and productive orchards. Air layers were done in plants of the Bengal cultivar using leafy and healthy woody branches, with about 0.010 to 0.015 m in diameter, in which were performed complete girdling with 0.020 m wide at a distance of 0.30 to 0.40 m below the apex. Then the branches were wrapped in moistened substrate. The layering was made at six times of theyear (January, March, May, July, September and November) and two substrates were used (coconut fiber and sphagnum) in a 6 x 2 factorial design in a randomized block with ten replicates. After 90 days, layers were separated from the matrix plant and evaluated for rooting and callus formation, root number, considering only the primary roots, length, area and volume of the roots, beyond the dry weight of roots and calluses. The months of January, March, September and November showed the best results for all analyzed variables related to rooting. With respect to the substrates, the only difference was in January and March to the root number and dry weight of roots, where the sphagnum showed the best results. The month of July was more conducive to the formation of calluses. The period between September and March was more suitable to the propagation of lychee, when there were rooting percentages above 90%, in addition to the formation of large amount of roots.

Litchi (Litchi chinensis) is an important subtropical fruit tree with high commercial value. However, the short and centralized fruit maturation period of litchi cultivars represents a bottleneck for litchi production. Therefore, the development of novel cultivars with extremely early fruit maturation period is critical. Previously, we showed that the genotypes of extremely early-maturing (EEM), early-maturing (EM), and middle-to-late-maturing (MLM) cultivars at a specific locus SNP51 (substitution type C/T) were consistent with their respective genetic background at the whole-genome level; a homozygous C/C genotype at SNP51 systematically differentiated EEM cultivars from others. The litchi gene on which SNP51 was located was annotated as flavonol synthase (FLS), which catalyzes the formation of flavonols. Here, we further elucidate the variation of the FLS gene from L. chinensis (LcFLS) among EEM, EM, and MLM cultivars. EEM cultivars with a homozygous C/C genotype at SNP51 all contained the same 2,199-bp sequence of the LcFLS gene. For MLM cultivars with a homozygous T/T genotype at SNP51, the sequence lengths of the LcFLS gene were 2,202-2,222 bp. EM cultivars with heterozygous C/T genotypes at SNP51 contained two different alleles of the LcFLS gene: a 2,199-bp sequence identical to that in EEM cultivars and a 2,205-bp sequence identical to that in MLM cultivar 'Heiye.' Moreover, the coding regions of LcFLS genes of other MLM cultivars were almost identical to that of 'Heiye.' Therefore, the LcFLS gene coding region may be used as a source of diagnostic SNP markers to discriminate or identify genotypes with the EEM trait. The expression pattern of the LcFLS gene and accumulation pattern of flavonol from EEM, EM, and MLM cultivars were analyzed and compared using quantitative real-time PCR (qRT-PCR) and high-performance liquid chromatography (HPLC) for mature leaves, flower buds, and fruits, 15, 30, 45, and 60 days after anthesis. Flavonol content and LcFLS gene expression levels were positively correlated in all three cultivars: both decreased from the EEM to MLM cultivars, with moderate levels in the EM cultivars. LcFLS gene function could be further analyzed to elucidate its correlation with phenotype variation among litchi cultivars with different fruit maturation periods. [ABSTRACT FROM AUTHOR]

ABSTRACT Obtaining leaf area is critical in several agronomic studies, being one of the important instruments to assess plant growth. The aim of this study was to estimate equations and select the most appropriate in determining leaf area in litchi (Litchi chinensis Sonn.). From the linear dimensions of length (L) and maximum width (W) of leaf limb, equations were estimated using linear, quadratic, potential and exponential models. The linear regression equation using the product of the length by maximum width, given by Y = 0.2885 + 0.662 (L.W) is the one that best expresses the leaf area estimation of litchi tree.

Abstract Oxidation of anthocyanin by polyphenol oxidase (PPO) or peroxidase (POD) causes enzymatic browning. It leads to undesirable characteristics of fruits and ultimately decreasing of fruit quality and value. Desiccation, post-harvest decay, loss of quality and micro cracking are the other most important problems restricting the growth of the litchi industry. Based on the fact, glutathione and citric acid inhibits the browning mechanism, the novel strategies of combining glutathione + citric acid with different packaging materials were used to improve litchi storability at refrigerated and room temperature. From the experiment, it was observed that, the application of glutathione (10 mmol/litre) and citric acid (100 mmol/litre) + polypropylene packet + corrugated fiber box gave good control on browning, weight loss, disease incidence and higher amount of anthocyanin in the litchi pericarp. High amount of TSS, total sugar, titratable acidity and ascorbic acid were also achieved in same treatments. Litchi fruits treated with combined application of glutathione and citric acid with packaging materials showed promising method to controlling browning and all the other quality parameters. [ABSTRACT FROM AUTHOR]

The extraction of litchi ( Litchi chinensis Sonn.) and oat ( Avena sativa L.) seeds were investigated using n-butane as pressurized solvent by evaluating the effect of pressure in the range of 7-100 bar and temperature from 25 to 70 °C on the extract yield and chemical composition together with the antioxidant activity of the extracts obtained. It was experimentally observed extraction yields for both seeds up to ~3.5 wt%, with a total phenolic content around 126.4 mg GAE/100 g of extract, and an antioxidant activity up to 78.36%. Oat seeds extract presented higher values of these parameters evaluated compared to litchi extract. Based on the results found, it seems that n-butane may be a promising solvent to conventional extraction methods, as mild operating conditions and eco-friendly solvent can be used to provide good results without any residues in the final product. [ABSTRACT FROM AUTHOR]

This study purposed to determine endogenous enzymes, color parameters, phytochemicals, antioxidant capacity, indicator microbes and acceptability of litchi pulps in syrup after pasteurization (90 °C/5 min) and pressurization (100–600 MPa/25 °C/20 min). The results showed that the polyphenoloxidase (PPO) and peroxidase (POD) activities in litchi still remained after pressurization, while pasteurization completely inactivated both enzymes. Moreover, the levels of ascorbic acid, total anthocyanins, total polyphenols and antioxidant activities (DPPH and FRAP assays) in pressurized samples were significant higher than those in heated one. Also, pressurization could preserve the natural color better than pasteurization. The microbiological contamination was noticeably inhibited after pasteurization and pressurization at 400–600 MPa. Pressurized pulps were shown to have the liking scores apparently higher than pasteurized pulp. In overall, pressurization at 600 MPa was an appropriate condition for decreasing the PPO and POD activities as well as the indicator microbes of litchi pulps in syrup. During refrigerated storage, browning index (BI) of pressurized pulp (600 MPa) was higher than that of thermally treated pulp, while the degradation of the phytochemicals and antioxidant activities in both processed products were observed. However, residual levels of both endogenous enzymes and antioxidant properties in pressurized pulp were still higher than those of pasteurized pulp throughout the storage period. [ABSTRACT FROM AUTHOR]

Pomace is frequently underestimated as a complex by-product. High pressure homogenisation (HPH), enzymatic hydrolysis (EH) and high hydrostatic pressure (HHP) modifications are applied to improve the functional properties of litchi pomace insoluble dietary fibre (LPDF). The relationships between physicochemical properties and structural alterations and digestibility of LPDF are studied. The results showed that HPH, EH and HHP changed the LPDF's microstructure, causing it to develop more porous structures. Meanwhile, HPH modification exhibited a remarkable effect on LPDF's water holding (15.6 g/g), water swelling (26.1 mL/g) and oil retention (5.4 g/g) capabilities, resulting in the change of the complexity of the neutral sugar side chain. Notably, the highest total phenol content (3.4 GAE mg/g) and antioxidant activities (DPPH 153.6, ABTS 188.9, FRAP 195.1 μmol Trolox/g) were also observed in LPDF modified with HPH. Moreover, the diversity of structural features and high affinity of modified LPDFs are conducive to its functional properties, i.e., inhibition of starch digestion. The remarkable potential of LPDF modified with HPH was attributed to the beneficial effects of dietary fibre on human health. As a result, litchi pomace could be a useful and effective source of functional fibres. The incorporation of litchi pomace into the human diet is still underexplored but is a promising alternative. • LPDF treated with the complex enzyme of cellulase and laccase notably increased the content of soluble dietary fibre. • The water holding capacity of LPDF could increase by 53% after HPH treatment. • H-LPDF showed an apparent inhibition effect on the digestion of maize starch. • The higher side chain branching complexity of LPDF favors the digestion inhibition properties. • Litchi pomace could be an efficient source of functional fibres. [ABSTRACT FROM AUTHOR]

Este trabalho teve como objetivo avaliar a aplicação de ácido cítrico em duas concentrações, associadas ou não à quitosana, na manutenção da qualidade de lichias 'Bengal'. Após a colheita e seleção, os frutos no estádio de maturação maduro foram imersos por 1 minuto nas seguintes soluções de ácido cítrico e de quitosana: [1] Testemunha - sem imersão; [2] ácido cítrico a 300 g L-1; [3] ácido cítrico a 300 g L-1 + 0,3% quitosana; [4] ácido cítrico a 300 g L-1 + 0,6% quitosana; [5] ácido cítrico a 600 g L-1; [6] ácido cítrico a 600 g L-1 + 0,3% quitosana; [7] ácido cítrico a 600 g L-1 + 0,6% quitosana. Após a imersão, os frutos foram colocados em gôndolas para escorrer o excesso de solução. Em seguida, foram armazenados em câmara fria, previamente higienizada, a 5ºC, durante 20 dias. O experimento foi conduzido seguindo um delineamento inteiramente casualizado, num esquema fatorial composto por sete soluções de recobrimento e cinco datas de amostragem. A cada cinco dias, foi avaliada a perda de massa fresca dos frutos, a coloração, o teor de antocianinas e a atividade das enzimas polifenoloxidase e peroxidase da casca. A solução de ácido cítrico a 600 g L-1, associada ou não à quitosana, e a combinação de quitosana 0,3% com 300 g L-1 de ácido cítrico foram as mais eficientes para a manutenção da cor avermelhada e a redução do escurecimento da casca de lichias 'Bengal' por 20 dias, a 5ºC.

Tropical evergreen perennials undergo recurrent flush growth, and their terminal buds alternate between growth and dormancy. In sharp contrast to intensive studies on bud development in temperate deciduous trees, there is little information about bud development regulation in tropical trees. In this study, litchi (Litchi chinensis Sonn.) was used as a model tropical perennial for morphological characterization and transcriptomic analysis of bud development. Litchi buds are naked with apical meristem embraced by rudimentary leaves, which are brown at dormant stage (Stage I). They swell and turn greenish as buds break (Stage II), and as growth accelerates, the rudimentary leaves elongate and open exposing the inner leaf primodia. With the outgrowth of the needle-like leaflets, bud growth reaches a maximum (Stage III). When leaflets expand, bud growth cease with the abortion of the rudimentary leaves at upper positions (Stage IV). Then buds turn brown and reenter dormant status. Budbreak occurs again when new leaves become hard green. Buds at four stages (Stage I to IV) were collected for respiration measurements and in-depth RNA sequencing. Respiration rate was lowest at Stage I and highest at Stage II, decreasing towards growth cessation. RNA sequencing obtained over 5 Gb data from each of the bud samples and de novo assembly generated a total of 59999 unigenes, 40119 of which were annotated. Pair-wise comparison of gene expression between stages, gene profiling across stages, GO/KEGG enrichment analysis, and the expression patterns of 17 major genes highlighted by principal component (PC) analysis displayed significant changes in stress resistance, hormone signal pathways, circadian rhythm, photosynthesis, cell division, carbohydrate metabolism, programmed cell death during bud development, which might be under epigenetic control involving chromatin methylation. The qPCR results of 8 selected unigenes with high PC scores agreed with the RPKM values obtained from RNA-seq. Three Short Vegetative Phase (SVP) genes, namely LcSVP1, LcSVP2 and LcSVP3 displayed different expression patterns, suggesting their differential roles in bud development regulation. The study brought an understanding about biological processes associated with the phase transitions, molecular regulation of bud development, as well as cyclic bud growth as a strategy to survive tropical conditions.

Lychee (Litchi chinensis Sonn.) has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. The objective of this study was to evaluate the shelf-life of 'Bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. Uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mM for 5 minutes + cassava starch 30 g L-1 for 5 minutes), 2-(immersion in hydrochloric acid 1 M for 2 minutes + starch cassava 30 g L-1 for 5 minutes), 3-(immersion in citric acid 100 mM for 5 minutes + polyvinyl chloride film (PVC, 14 µm thick)) and 4-(immersion in hydrochloric acid 1 M for 2 minutes + PVC film). During 20 days, the fruits were evaluated for mass loss, pericarp color, pH, soluble solids and titratable acidity, vitamin C of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. The treatment with hydrochloric acid associated with PVC was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. The cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.A lichia (Litchi chinensis Sonn.) possui alto valor comercial no mercado, entretanto, apresenta vida útil pós-colheita curta, por causa do rápido escurecimento do pericarpo. O objetivo deste trabalho foi avaliar a vida útil pós-colheita de lichias 'Bengal', armazenadas após tratamento com ácido clorídrico e ácido cítrico, associados a fécula de mandioca e embalagem plástica. Frutos com pericarpos uniformemente vermelhos foram submetidos aos tratamentos: 1-( imersão em ácido cítrico 100 mM por 5 minutos + fécula de mandioca 30 g/L por 5 minutos); 2-( imersão em ácido clorídrico 1 M por 2 minutos + fécula de mandioca 30 g/L por 5 minutos); 3-( imersão em ácido cítrico 100 mM por 5 minutos + filme de policloreto de vinila (PVC ,14 µm de espessura)); e 4-( imersão em ácido clorídrico 1 M por 2 minutos + filme de PVC). Durante 20 dias, os frutos foram avaliados quanto à perda de massa fresca, cor do pericarpo, pH, teor de sólidos solúveis e acidez titulável da polpa, vitamina C do pericarpo e da polpa e atividades de polifenoloxidase e peroxidase do pericarpo. O tratamento com ácido clorídrico associado ao PVC foi o mais efetivo na manutenção da cor vermelha e o que melhor conservou as características de qualidade dos frutos. A fécula de mandioca associada ao ácido cítrico e ácido clorídrico não reduziu a perda de massa e não impediu o escurecimento do pericarpo de lichia.

Foram avaliados os efeitos da imersão em soluções com diferentes concentrações de ácido clorídrico (HCl) sobre a redução do escurecimento do pericarpo e a conservação pós-colheita de lichia. Lichias 'Bengal' foram colhidas com o pericarpo completamente vermelho e imersas por dois minutos em 0 (controle); 0,25; 0,5; 1,0 e 2,0 M de HCl. Após os tratamentos, os frutos foram acondicionados em bandejas de poliestireno expandido e recobertos com filme de policloreto de vinila (PVC). Os frutos foram armazenados em câmara fria a 10,0 ± 0,9°C e 90 ± 5% de UR e avaliados de 4 em 4 dias. Após 24 dias de armazenamento, os frutos de todos os tratamentos apresentaram perda de massa fresca em torno de 4,5%. Até o 16º dia de armazenamento, os frutos tratados com HCl 2,0 M não apresentaram alteração significativa na coloração do pericarpo (ΔE, h e L*) em relação ao dia da colheita. Visualmente, esses frutos permaneceram sem alterações perceptíveis na coloração, até os 24 dias de armazenamento refrigerado. Naqueles não tratados (controle) e nos tratados com HCl a 0,25M e 0,5 M, o escurecimento do pericarpo iniciou-se no 4º dia de armazenamento refrigerado.

Objetivou-se determinar as respostas fisiológicas e bioquímicas associadas ao uso de etileno e 1-metilciclopropeno (1-MCP) na conservação pós-colheita de lichias, assim como a influência desses tratamentos isolados ou combinados no escurecimento desses frutos. Após a colheita, foram aplicados os seguintes tratamentos: sem aplicação de 1-MCP ou etileno; etileno (20µL L-1, por 6 horas); 1-MCP (300nL L-1, por 12 horas) e etileno (20µL L-1, por 6 horas) + 1-MCP (300nL L-1, por 6 horas). Após os tratamentos, os frutos foram armazenados a 5°C e 90% UR durante 30 dias, sendo avaliados a cada 10 dias (+3 dias de comercialização simulada a 25°C e 65% UR). Avaliou-se a produção de etileno, taxa respiratória, sólidos solúveis (SS), perda de massa fresca, coloração (luminosidade - L* e a*) e atividade da polifenoloxidase (PPO). A produção de etileno e taxa respiratória não apresentaram diferenças significativas entre os tratamentos e os SS decresceram ao longo do armazenamento, mas também sem diferenças entre os tratamentos. A atividade da enzima PPO foi aumentada, sendo correlacionada com os índices decrescentes de L* e a* presentes nos frutos, ocorrendo, paralelamente, aumento da perda de massa dos frutos. Conclui-se que o escurecimento do pericarpo da lichia está relacionado à perda de massa fresca e aumento da atividade da PPO e que nenhum dos tratamentos utilizados evitou o escurecimento dos frutos.The objective was to determine the physiological and biochemical changes associated with the use of ethylene and 1-methylcyclopropene (1-MCP) on postharvest conservation of lychees as well as the influence of these treatments alone or in combination on skin browning of fruit. After harvest, it was applied the following treatments: without application of 1-MCP or ethylene, ethylene (20mL L-1 for 6 hours), 1-MCP (300nL L-1 for 12h) and ethylene (20mL L-1 for 6 hours) + 1-MCP (300nL L-1 for 6 hours). After treatments, fruits were stored at 5°C and 90% RH for 30 days and were evaluated every 10 days (+3 days of simulated marketing at 25°C and 65% RH). The ethylene production, respiration rate, soluble solids (SS), weight loss, color (lightness - L * and a*) and polyphenoloxidase activity (PPO) were evaluated. Ethylene production and respiration rate showed no significant differences between treatments, and SS decreased over the storage, but there was also no difference between treatments. The enzyme activity showed an increase in PPO, which was correlated to the decreasing rates of L * and a*, occurring in parallel, increased fruit weight loss. It is concluded that the skin browning of lychee is related to weight loss and increased activity of PPO, and that none of the treatments prevented the sking browning of fruit.

After harvesting litchi, the red color of the fruit pericarp is rapidly lost resulting in discoloration and browning during storage and marketing. The loss of the red color is caused by the degradation or loss of stability of anthocyanins. The action of peroxidase and polyphenoloxidase is usually related to the browning and discoloration of fruits of various species. This study aimed to evaluate the influence of pH and temperature on peroxidase and polyphenoloxidase activities, in a partially purified preparation of pericarp of the litchi cultivar Bengal. Fruits were harvested at the ripe stage and polyphenoloxidase was partially purified by sequential saturation in 80% ammonium sulfate. At concentrations of 40-50% and 60-70% ammonium sulfate the activities of polyphenoloxidase and peroxidase were, respectively, 124 times and 158 times higher than in the crude extract. The activity of peroxidase and polyphenoloxidase was maximum at pH 6.5 and 7.0, respectively, and no activity was detected at pH 2.5 and 9.5. Pre-incubation of the enzyme extract for 45 min at pH 2.5 or 9.5 completely inactivated the enzymes, with the highest degree of efficiency at pH 2.5. Peroxidase activity was highest at 70ºC and remained active for a period of 120 min at 70 and 80ºC. Peroxidase became completely inactive when maintained at 90ºC for 10 min or 1 min at 100ºC. Polyphenoloxidase activity was highest at 20ºC and remained active for a period of 120 min at 40 and 50ºC and was inactivated after 10 min at 60ºC. Due to the high temperature of inactivation of the peroxidase and polyphenoloxidase activities, the enzymes can be inactivated more easily in fruits using acid or alkaline solutions.Após a colheita do fruto, a cor vermelha do pericarpo da lichia é rapidamente perdida, o que resulta em descoloração e escurecimento durante o armazenamento e comercialização. A perda da cor vermelha é devido à degradação de antocianinas ou à perda de sua estabilidade. Usualmente, a ação da peroxidase e polifenoloxidase está relacionada ao escurecimento e à descoloração de várias frutas. Avaliou-se a influência do pH e da temperatura na atividade da peroxidase e polifenoloxidase em uma preparação purificada parcial de pericarpo de cultivar Bengal. Os frutos foram colhidos no estádio vermelho maduro. A polifenoloxidase foi parcialmente purificada por saturação seqüencial até 80% de sulfato de amônio. Na concentração de 40-50% e de 60-70% de sulfato de amônio, a atividade da polifenoloxidase e peroxidase foi 124 e 158 vezes maior vezes maior do que a encontrada no extrato cru. A peroxidase e polifenoloxidase apresentaram ótima atividade em pH 6,5 e 7,0 e nenhuma atividade foi detectada a pH 2,5 e 9,5. A pré-incubação do extrato das enzimas até 45 min a pH 2,5 ou 9,5 inativou completamente as enzimas, sendo que o maior grau de eficiência ocorreu em pH 2,5. A peroxidase apresentou maior atividade a 70ºC, permanecendo ativa durante um período de 120 min a 70 e 80ºC. A peroxidase tornou-se completamente inativa, quando aquecida durante 10 min a 90ºC ou durante 1 min a 100ºC. A polifenoloxidase apresentou maior atividade a 20ºC, permanecendo ativa durante um período de 120 min a 40 e 50ºC e inativada aos 10 min a 60ºC. Devido à alta temperatura para inativação, a atividade da peroxidase e polifenoloxidase pode ser reduzida, imergindo os frutos em soluções ácidas ou alcalinas.

Este experimento visou a estudar o efeito de diferentes temperaturas e tempos de pré-resfriamento em água sobre a qualidade de lichias 'B3', após a frigoconservação. Os tratamentos foram: T1 = controle (sem pré-resfriamento); T2 = imersão por cinco minutos em água a 2,5°C; T3 = imersão por 10 minutos em água a 2,5°C; T4 = imersão por 20 minutos em água a 2,5°C; T5 = imersão por sete minutos em água a 6°C; T6 = imersão por 20 minutos em água a 8°C e T7 = imersão por 10 minutos em água a 10°C. Após a aplicação dos respectivos tratamentos, os frutos foram acondicionados em filmes de polietileno de 24µm, selados e posteriormente armazenados a 5°C e 90% UR, por um período de sete dias, seguido por três dias de comercialização simulada a 20°C e 70% UR. O delineamento experimental foi inteiramente ao acaso, com tratamentos fatoriais de 7x3 (tratamentosxtempo). Foram utilizadas quatro repetições por tratamento, sendo cada uma composta por 150g de frutos. Determinaram-se: perda de massa fresca, coloração (L*, a e b), escurecimento (%) e podridões (%). De acordo com os resultados, o pré-resfriamento com água reduz a percentagem de escurecimento, o decréscimo da luminosidade (L*) e os valores de a. Por outro lado, esse tratamento favorece o surgimento de altos índices de podridão.This project studied the effects of different precooling temperatures and times with water on lychee 'B3' fruit quality cold storage. The treatments were: T1 = control (without precooling); T2 = immersed in water at 2.5°C for five minutes; T3 = immersed in water at 2.5°C for ten minutes; T4 = immersed in water at 2.5°C for 20 minutes; T5 = immersed in water at 6°C for seven minutes; T6 = immersed in water at 8°C for 20 minutes and T7 = immersed in water at 10°C for ten minutes. After treatments application, the fruits were then placed into polyethylene bags of 24µm, sealed, and stored for seven days at 5°C and 90% RH, plus 3 days at 20°C and 70% RH to simulate commercial conditions. Completely randomized experimental design, with factorial 7x3 (treatments x time). The research used four replicates for treatment, approximately 150g. It was determined: weight loss, color (L*, a and b), browning (%) and rots (%). According to the results, the lychee hydrocooling reduced the browning percentage, the brightness decrease (L *) and a values. In the other hand, this treatment also resulted in higher percentage of rots.

Originária da região sudeste da China, a lichieira tem apresentado significativo crescimento em área cultivada nos últimos anos devido aos excelentes sabor e aroma dos frutos. Porém, alternâncias de produção, associadas ao baixo vingamento de frutos, são problemas importantes da cultura. O raleio de frutos pode contribuir para a redução da alternância de produção e aumentar o percentual de frutos comercializáveis e de melhor qualidade, através do ganho em tamanho. Objetivou-se, neste trabalho, avaliar o efeito do raleio de frutos em lichieira 'Bengal' para as condições de cultivo em Viçosa, Minas Gerais. O experimento foi conduzido no delineamento experimental em blocos casualizados, com 5 tratamentos e 7 repetições, sendo cada planta uma repetição. Os tratamentos consistiram em diferentes intensidades de raleio manual representados pelo número de frutos deixados nas panículas do ramo terminal, sendo: T1: 3 frutos/ramo; T2: 6 frutos/ramo; T3: 9 frutos/ramo; T4: 12 frutos/ramo; T5: sem raleio (controle). Analisaramse o comprimento longitudinal e equatorial dos frutos (cm), a massa de fruto (g); a massa da casca, polpa e semente (g); o teor de sólidos solúveis totais (ºBrix); a acidez titulável da polpa (% ácido málico); a percentagem de matéria seca da polpa, casca e semente (%) e a percentagem de queda natural (%). Observou-se efeito do raleio somente para as variáveis teor de sólidos solúveis totais, percentagem de queda natural e massa de matéria seca da casca, não se justificando o raleio em frutos de lichieira.Original from the southeast of China, the litchi has been presenting significant growth in the areas cultivated in the last years due to the excellent flavor and aroma of the fruits. However, production alternations, associated to the low setting of fruits, are important problems of the culture. The thinning of fruits can contribute to the reduction of the production alternation and increase both the percentile of marketable fruits and the ones of better quality by the gains in relation to size. It was aimed at this work to evaluate the effect of the thinning of fruits in litchi 'Bengal' for the cultivation conditions in Viçosa, Minas Gerais, and Brazil. The experiment was designed in complete randomized blocks, with 5 treatments and 7 repetitions, and each plant was a repetition. The treatments consisted of different intensities of thinning acted by the number of fruits left in the panicles of the terminal twigs, as T1: 3 fruit/twigs; T2: 6 fruit/twigs; T3: 9 fruit/twigs; T4: 12 fruit/twigs; T5: not thinning (controls). It was analyzed the longitudinal and the equatorial length of the fruits (cm), the fruit mass (g); the mass of the skin, pulp and seed (g); total soluble solids content (ºBrix); total titratable acidity (% malic acid); the percentage of dry matter of the pulp, skin and seed (%) and the percentage of natural fall (%). Effect of the thinnig was only observed for the variable total soluble solid contents, percentage of natural fall and mass of dry matter of the skin, and it was impossible to justify the thinning in litchi fruits.

Objetivou-se, no presente trabalho, avaliar o efeito da aplicação de AIB e diferentes tipos de substratos na propagação vegetativa de lichia via técnica de alporquia. Os alporques foram realizados em ramos semilenhosos, sadios e vigorosos da cultivar Bengal, com 12 anos de idade. Os ramos foram anelados com 1,5 cm de largura, tratados com diferentes concentrações de AIB (0; 1.000; 2.000; 3.000 e 4.000 mg.L-1), distribuídos em solução com auxílio de pincel e cobertos com três diferentes tipos de substratos (plantmax®, húmus e esfagno) umedecidos. Em seguida, foram envolvidos com plástico transparente e amarrados nas duas extremidades, para criar um ambiente úmido ao redor da lesão, favorável ao desenvolvimento de raízes, para a produção dos alporques. Após 84 dias, avaliaram-se o comprimento de raiz (cm), o número de raízes, expresso em notas de 0 a 5, e a porcentagem de calejamento e de enraizamento. Maior sucesso na propagação vegetativa de lichia, cultivar Bengal, via técnica de alporquia, foi obtido utilizando como substrato o plantmax® AIB entre 2.166 e 2.430 mg.L-1. A utilização de húmus combinado com concentrações entre 2.175 e 2.250 mg.L-1 de AIB também proporcionou bons resultados no desenvolvimento dos alporques. Por outro lado, menor sucesso no desenvolvimento dos alporques de lichia, cultivar Bengal, independentemente da concentração de AIB utilizada, foi obtido com esfagno.The objective of the present research was to evaluate the effect of the IBA application and different kinds of substrates in the vegetative propagation of litchi by air layering technique. The air layering had been done in semi-hardwood, healthy and vigorous branches of cultivar Bengal, in stock plants of 12 years old. The branches had been ring-girdled, 1,5 cm of width, and the exposed wound treated with different IBA concentrations (0, 1000, 2000, 3000 and 4000 mg.L-1), enclosed with three moistened substrates (plantmax®, humus and sphagnum moss), involved with transparent plastic and tied in the two extremities. After 84 days, it was evaluated the length of root (cm), number of root expressed in notes from 0 to 5, percentage of callus and rooting. The best results in the vegetative propagation of litchi, cultivar Bengal, by air layering technique were obtained using plantmax® and IBA between 2.166 and 2.430 mg.L-1. The use of humus combined with concentrations between 2.175 and 2.250 mg.L-1 of IBA, also gave good results in the development of air layering. The poor success independently of IBA concentration was gotten with the use of sphagnum moss.

The high level of physiological fruitlet abscission in litchi (Litchi chinensis Sonn.) causes severe yield loss. Cell separation occurs at the fruit abscission zone (FAZ) and can be triggered by ethylene. However, a deep knowledge of the molecular events occurring in the FAZ is still unknown. Here, genome-wide digital transcript abundance (DTA) analysis of putative fruit abscission related genes regulated by ethephon in litchi were studied. More than 81 million high quality reads from seven ethephon treated and untreated control libraries were obtained by high-throughput sequencing. Through DTA profile analysis in combination with Gene Ontology and KEGG pathway enrichment analyses, a total of 2,730 statistically significant candidate genes were involved in the ethephon-promoted litchi fruitlet abscission. Of these, there were 1,867 early-responsive genes whose expressions were up- or down-regulated from 0 to 1 d after treatment. The most affected genes included those related to ethylene biosynthesis and signaling, auxin transport and signaling, transcription factors, protein ubiquitination, ROS response, calcium signal transduction and cell wall modification. These genes could be clustered into 4 groups and 13 subgroups according to their similar expression patterns. qRT-PCR displayed the expression pattern of 41 selected candidate genes, which proved the accuracy of our DTA data. Ethephon treatment significantly increased fruit abscission and ethylene production of fruitlet. The possible molecular events to control the ethephon-promoted litchi fruitlet abscission were prompted out. The increased ethylene evolution in fruitlet would suppress the synthesis and polar transport of auxin and trigger abscission signaling. To the best of our knowledge, it is the first time to monitor the gene expression profile occurring in the FAZ-enriched pedicel during litchi fruit abscission induced by ethephon on the genome-wide level. This study will contribute to a better understan

Massive young fruit abscission usually causes low and unstable yield in litchi (Litchi chinensis Sonn.), an important fruit crop cultivated in tropical and subtropical areas. However, the molecular mechanism of fruit drop has not been fully characterized. This study aimed at identification of molecular components involved in fruitlet abscission in litchi, for which reference genome is not available at present. An improved de novo transcriptome assembly was firstly achieved by using an optimized assembly software, Trinity. Using improved transcriptome assembly as reference, digital transcript abundance (DTA) profiling was performed to screen and identify candidate genes involved in fruit abscission induced by girdling plus defoliation (GPD), a treatment significantly decreased the soluble sugar contents causing carbohydrate stress to fruit. Our results showed that the increasing fruit abscission rate after GPD treatment was associated with higher ethylene production and lower glucose levels in fruit. A total of 2,771 differentially expressed genes were identified as GPD-responsive genes, 857 of which were defined by GO and KEGG enrichment analyses as the candidate genes involved in fruit abscission process. These genes were involved in diverse metabolic processes and pathways, including carbohydrate metabolism, plant hormone synthesis and signaling, transcription factor activity and cell wall modification that were rapidly induced in the early stages (within 2 d after treatment). qRT-PCR was used to explore the expression pattern of 15 selected candidate genes in the abscission zone, pericarp and seed, which confirmed the accuracy of our DTA data. More detailed information for different functional categories was also analyzed. This study profiled the gene expression related to fruit abscission induced by carbohydrate stress at whole transcriptome level and thus provided a better understanding of the regulatory mechanism of young fruit abscission in litchi.

Tropical evergreen perennials undergo recurrent flush growth, and their terminal buds alternate between growth and dormancy. In sharp contrast to the intensive studies on bud development in temperate deciduous trees, there is little information about bud development regulation in tropical trees. In this study, litchi (Litchi chinensis Sonn.) was used as a model tropical perennial for morphological characterization and transcriptomic analysis of bud development. Litchi buds are naked with apical meristem embraced by rudimentary leaves, which are brown at dormant stage (Stage I). They swell and turn greenish as buds break (Stage II), and as growth accelerates, the rudimentary leaves elongate and open exposing the inner leaf primodia. With the outgrowth of the needle-like leaflets, bud growth reaches a maximum (Stage III). When leaflets expand, bud growth cease with the abortion of the rudimentary leaves at upper positions (Stage IV). Then buds turn brown and reenter dormant status. Budbreak occurs again when new leaves become hard green. Buds at four stages (Stage I to IV) were collected for respiration measurements and in-depth RNA sequencing. Respiration rate was the lowest at Stage I and highest at Stage II, decreasing toward growth cessation. RNA sequencing obtained over 5 Gb data from each of the bud samples and de novo assembly generated a total of 59,999 unigenes, 40,119 of which were annotated. Pair-wise comparison of gene expression between stages, gene profiling across stages, GO/KEGG enrichment analysis, and the expression patterns of 17 major genes highlighted by principal component (PC) analysis displayed significant changes in stress resistance, hormone signal pathways, circadian rhythm, photosynthesis, cell division, carbohydrate metabolism, programmed cell death during bud development, which might be under epigenetic control involving chromatin methylation. The qPCR results of 8 selected unigenes with high PC scores agreed with the RPKM values obtained from RNA-seq. Three Short Vegetative Phase (SVP) genes, namely LcSVP1, LcSVP2, and LcSVP3 displayed different expression patterns, suggesting their differential roles in bud development regulation. The study brought an understanding about biological processes associated with the phase transitions, molecular regulation of bud development, as well as cyclic bud growth as a strategy to survive tropical conditions. [ABSTRACT FROM AUTHOR]

Glycosylation plays a major role in the diversity in the chemical compositions of flavonoids. In this study, we performed biochemical and molecular assays to identify a glucosyltransferase gene responsible for the anthocyanin composition in litchi. Cyanidin-3-glucoside and cyanidin-3-rutinoside were predominant anthocyanins in the red pericarp and young leaf of litchi. Anthocyanin composition varied among litchi varieties. Anthocyanin profile was primarily determined by genetic factors. Higher activities of UDP-rhamnose: cyanidin-3-glucoside rhamnosyltransferase (CGRT) were detected in the pericarps of the cyanidin-3-rutinoside predominant varieties. Three full-length putative UDP-rhamnose: flavonoid glycoside 2″-O-beta-l-rhamnosyltransferase-like genes were isolated and designated as LcFGRT2, LcFGRT4, and LcFGRT5. Phylogenetic analysis showed that these genes were clustered with other glucoside-glycosyltransferases. Notable activities in catalyzing cyanidin-3-rutinoside formation were observed in extracts of tobacco leaves and yeast with heterologous expression of LcFGRT4. However, the expression pattern of LcFGRT4 did not agree with the CGRT activity. This result suggests that the difference in CGRT among varieties occurred post-transcriptionally. Nucleotide variation in LcFGRT4 was surveyed by sequencing 30 litchi accessions with different anthocyanin profiles. Eight non-synonymous single-nucleotide polymorphisms were detected. Type A LcFGRT4 sequence (LcFGRT4A) was observed in cyanidin-3-glucoside-dominant varieties, whereas type B LcFGRT4 sequence (LcFGRT4B) was detected in cyanidin-3-glucoside-dominant varieties. A mutant in 343 C/G polymorphism was targeted as the critical point responsible for the CGRT activity. Results indicated that a single-point mutation in LcFGRT4 could alter the activity of CGRT and may contribute to the diverse anthocyanin profile of litchi. [ABSTRACT FROM AUTHOR]

Key message: A novel LcGST4 was identified and characterized from Litchi chinensis . Expression and functional analysis demonstrated that it might function in anthocyanin accumulation in litchi. Abstract: Glutathione S-transferases (GSTs) have been defined as detoxification enzymes for their ability to recognize reactive electrophilic xenobiotic molecules as well as endogenous secondary metabolites. Anthocyanins are among the few endogenous substrates of GSTs for vacuolar accumulation. The gene encoding a GST protein that is involved in anthocyanin sequestration from Litchi chinensis Sonn. has not been reported. Here, LcGST4, an anthocyanin-related GST, was identified and characterized. Phylogenetic analysis showed that LcGST4 was clustered with other known anthocyanin-related GSTs in the same clade. Expression analysis revealed that the expression pattern of LcGST4 was strongly correlated with anthocyanin accumulation in litchi. ABA- and light-responsive elements were found in the LcGST4 promoter, which is in agreement with the result that the expression of LcGST4 was induced by both ABA and debagging treatment. A GST activity assay in vitro verified that the LcGST4 protein shared universal activity with the GST family. Functional complementation of an Arabidopsis mutant tt19 demonstrated that LcGST4 might function in anthocyanin accumulation in litchi. Dual luciferase assay revealed that the expression of LcGST4 was activated by LcMYB1, a key R2R3-MYB transcription factor that regulates anthocyanin biosynthesis in litchi. [ABSTRACT FROM AUTHOR]

In this study, we documented whether pollen parents are required for fruiting and their effects on fruit set and seed characteristics in field-grown '73-S-20' litchi (Litchi chinensis Sonn.). The effects of preventing female (F) flower pollination to induce parthenocarpy, selfing, and outcrossing with 'Haak Yip' and open-pollinated (OP) fruits derived from F flowers and the second wave of the male (M2) flowers of 'Haak Yip' blooming in synchrony were assessed. The correlation between the percentage of fruit set and shriveled seed/seed weight in self-crossed and outcrossed fruits was calculated. At harvest, the absence of pollination induced a high proportion of parthenocarpic fruit without seed, although the fruit weighed only 4.2 g. Fruit set with outcrossing was greater than that with selfing and the percentage of shriveled seed obtained in self-crossed fruits was much greater than that in outcrossed fruits but not different from that in OP fruits, suggesting that outcrossing increased but selfing decreased the cluster yield and seed weight. However, 33.3% and 23.0% of seed contained embryos in selfed and OP fruits, respectively. No positive correlation between the percentage of fruit set and shriveled seed/seed weight was found, indicating that seed abortion during development was not the key factor leading to low yield. We concluded that tiny parthenocarpic fruit could be obtained but that pollination is essential for the good yield of '73-S-20'. Outcrossing markedly increased fruit set and seed weight and decreased the percentage of shriveled seed. Factors other than the pollen parents may be involved in the seed development of '73-S-20'. [ABSTRACT FROM AUTHOR]

Litchi ( Litchi chinensis Sonn., L. chinensis), a type of tree growing in most areas of southern China, produces an edible fruit that is also a source of traditional medicine. Genetic identification of litchi species or cultivars using molecular markers is very important. In this study, a total of six litchi samples from Fujian, Hainan, Guangdong, Guangxi and Sichuan province, as well as one wild Dimocarpus confinis ( D. confinis) sample from Guangxi province were collected for genetic analysis. The cluster dendrograms were constructed for genetic analysis on the basis of DNA amplification results by RAPD and ISSR. The improved RAPD amplified DNA with consistent and clear banding patterns. A total of 176 bands were found, indicating a 72.7 % polymorphism in L. chinensis DNA samples. Significant genetic distances were found among the different species or cultivars, with an index of similarity coefficient ranging from 0.59 to 0.87. Similar to RAPD results, ISSR analysis of the L. chinensis DNA samples showed a range of 0.70-0.93 similarity coefficients. The genetic distance between Hainan sample and Sichuan samples was the farthest, which is consistent with their geographic distance. Furthermore, the index of similarity coefficient between D. confinis and L. chinensis was 0.35-0.41 by RAPD and 0.38-0.48 by ISSR, indicating that these two species have significant genetic difference. This study reveals the high level of genetic differences between different litchi species or cultivars, and confirms the significance of the improved RAPD method in genetic characterization of organisms. Taken together, the improved RAPD combined with ISSR analysis can be used frequently for the genetic diversity, germplasm resources preservation, molecular-assisted breeding, and genetic characterization of various organisms. [ABSTRACT FROM AUTHOR]

Understanding of the shoot growth pattern and precise determination of flush maturation time is the key to targeted management of flush cycle, which is important for productivity of litchi. In this study, the shoot growth rhythm and changes in leaf greenness and functionality in developing leaves were studied for two consecutive years in litchi (Litchi chinensis Sonn.), a typical tree species with delayed greening leaves. Two cultivars 'Baili' and 'Heiye' with significant difference in leaf greenness were compared. The study showed that the shoot growth was cyclic but the stem expansion continued until winter. Leaf greenness, indicated by SPAD value, increased with leaf maturation following a modified logistic model. The asymptotic deceleration point (PDA) was assumed as the full maturity point of the new leaves, when their SPAD value had increased to 90% of its maximum (Vmax). The average SPAD values at PDA were 45 and 31 in 'Heiye' and 'Baili', respectively. At this point, maximal net CO2 assimilation (A) and photochemical efficiency of photosystem II (PSII) (Fv/Fm) were attained. The average growing degree days (GDD) for flush growth from bud break till SPAD value reached PDA across seasons were similar in 'Baili' and 'Heiye' (587.4°D vs 546.7°D). It was concluded that the apical meristem of litchi alternates between resting and active states, while the vascular cambium maintains active state throughout the growth season. SPAD meter provides a rapid and non-destructive technique to indicate the flush maturity of litchi with delayed greening leaves. Thermal time for flush growth was not significantly different between the two cultivars despite their great difference in leaf greenness. [ABSTRACT FROM AUTHOR]

A lichia é uma frutífera originária da China, sendo considerada em todo o mundo como a “Rainha das frutas” por sua aparência e sabor delicado, semelhante ao da uva “Itália” e com aspecto similar a um morango. No Brasil, as regiões de expressiva produção são os estados de São Paulo e Paraná. A comercialização desta fruta no Brasil ainda é pequena, concentrando-se em algumas cidades de maior porte como São Paulo e Rio de Janeiro. O preço da fruta in natura oscila entre R$ 5,00 e R$ 15,00/kg dependendo da região. As pesquisas em torno da lichieira têm sido intensificadas nos últimos anos. No entanto, no Brasil, apesar da potencialidade de exploração comercial da cultura, os poucos estudos realizados centralizam-se nos frutos e não na planta como um todo. A propagação da lichieira pode ser realizada tanto de forma sexuada quanto assexuada. Por via sexual, a propagação de lichia apresenta alguns entraves como perda rápida de viabilidade, ocorrência de segregação varietal e presença de longo período juvenil (10 anos ou mais para começar a produzir frutos). Assexualmente, ela é propagada via alporquia, enxertia ou estaquia, sendo a alporquia o método mais comum. A alporquia apresenta consideráveis obstáculos à expansão da cultura no Brasil, pois além dela ser considerado um procedimento caro, esse método de propagação possui baixo rendimento e produz pequeno número de mudas por planta matriz. Além disso, a alporquia proporciona graves danos à planta matriz, devido à quantia de anelamentos efetuados (Raharjo e Litz, 2005). O Brasil tem elevado potencial para se tornar grande produtor desta fruta, podendo gerar excedentes para exportação, visto que o país possui clima propício para expansão desta cultura, que se adapta bem ao clima subtropical. A cultura de tecidos vegetais é uma técnica que permite otimizar o processo produtivo de muitas espécies vegetais, fazendo com que espécies de difícil propagação sejam multiplicadas in vitro. Plântulas germinadas in vitro a partir de sementes são excelentes fontes de explantes para diversos processos in vitro devido à sanidade e vigor das plântulas obtidas. Assim, alternativas de propagação assexual por cultura de tecidos para a lichieira podem ser úteis para sanar estes entraves de propagação desta espécie otimizando o processo produtivo. Todavia, são restritos os trabalhos na literatura visando à propagação via cultura de tecidos desta espécie. Raharjo e Litz (2005) mostraram que é possível regenerar plantas de lichia cv. ‘Brewster’ por meio da embriogênese somática a partir de embriões imaturos, sendo o primeiro relato de embriogênese somática em lichia. O objetivo deste trabalho foi estudar a germinação de sementes de lichia in vitro em função de agentes de desinfestação e avaliar o potencial de explantes foliares juvenis na indução de calos.