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This study analyzed physiological and molecular characteristics associated with the resistance to aging or anti-senescence in Camellia oleifera Abel. Trees over 100 years old (ancient trees) were compared with those about 30 years old (mature trees). Total chlorophylls, chlorophyll a/b ratio, and hydrogen peroxide concentrations in ancient tree leaves were significantly higher than in their counterparts. Significantly higher activities of superoxide dismutase, peroxidase, and catalase were detected in ancient tree leaves. Nine Chl a/b-binding protein genes, 15 antioxidant enzyme genes, 21 hormone-related genes, and 301 stress-related genes were upregulated, and 42 protein-degradation genes were downregulated in ancient tree leaves. By increasing chlorophyll content and antioxidant enzyme activities and regulating the ageing-related genes expression, ancient C. oleifera leaves maintained remarkable vitality. Although further research is needed, our study may shed some light on how ancient C. oleifera trees can resist ageing and sustain their healthy growth. [ABSTRACT FROM AUTHOR]

To clarify the effect of leaf scorch on walnut leaf photosynthesis, photosynthetic parameters were measured in Juglans regia 'Wen185' and 'Xinxin2' symptom trees (WS, XS) and symptomless trees (WH, XH). At the early stage of infection and under the low-grade leaf scorch, WS showed significantly lower net photosynthetic rate (PN), stomatal limitation (Ls), and higher intercellular CO2 concentration (Ci) than those of WH. However, at the mid to late stage of infection and under the high-grade leaf scorch, WS showed significantly lower PN, Ci, the maximal quantum yield of PSII photochemistry and higher Ls, minimal fluorescence yield of the dark-adapted state, nonphotochemical quenching than those of WH, which would occur once Juglans regia 'Xinxin2' was infected. The above results indicated the effect of leaf scorch on walnut leaf photosynthesis was related to the walnut varieties and the duration and severity of the disease. Under the influence of leaf scorch, the decline in photosynthesis of Juglans regia 'Wen185' leaves changed from stomatal to nonstomatal restriction, while Juglans regia 'Xinxin2' leaves showed always nonstomatal restriction. [ABSTRACT FROM AUTHOR]

Lycium barbarum Thunb. and Lycium ruthenicum Murray (wolfberries) have been utilized as traditional medicinal and nutritional plants in China for centuries. Much research has been focused on their high quality, yet the molecular mechanisms underlying morphological differences remain unclear. In this study, a comparative analysis of morphological and cytological characteristics indicated that significant differences existed. Meanwhile, transcriptomic analyses of the flower and fruit were performed at different developmental stages, and a total of 54 795 differentially expressed genes (DEGs) were screened. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that these DEGs were significantly enriched in substance metabolism, catalytic activity, single organism process, starch and sucrose metabolism, carotenoid biosynthesis, amino sugar and nucleotide sugar metabolism, phenylpropanoid biosynthesis, and other pathways. Based on these significantly enriched pathways, the ratio between nonsynonymous and synonymous substitution rates (Ka/Ks), and numerous studies related to flower and fruit development, we preliminarily screened eight transcription factor families related to flower and fruit development and counted the number of potential transcription factor genes. These candidate genes could provide a basis for future functional verification, helping to further research on the molecular mechanism of morphological differences in the two Lycium species. [ABSTRACT FROM AUTHOR]

Mesembryanthemum crystallinum is a model halophyte that switches from C3 photosynthesis to Crassulacean acid metabolism (CAM) upon extreme abiotic stresses. This study aimed to investigate alkalinity-induced root transcriptome profiling in M. crystallinum. M. crystallinum seedlings were treated with 50 mM sodium bicarbonate (NaHCO3; pH 7.5) and 90 mM NaHCO3 (pH 9.5) for 7 d, respectively. Alkalinity-induced differentially expressed genes (DEGs) were identified and annotated. Functional enrichment analysis was performed for DEGs. The expression of genes related to response to stress and CAM were analyzed and compared. Comparing with control, 50 and 90 mM NaHCO3 treatments induced 4 027 and 25 403 DEGs in M. crystallinum roots, respectively. Among these DEGs, 832 and 131 DEGs were consistently upregulated and downregulated by both stresses, respectively. These genes were associated with multiple biological processes related to response to abiotic stresses. Alkaline stress upregulated genes encoding heat shock proteins and ethylene-related genes, but downregulated genes encoding glutathione S-transferases. Also, genes that encode phosphoenolpyruvate carboxylases, phosphoenolpyruvate carboxylase kinase 1, and malate dehydrogenases related to malate accumulation were upregulated by alkalinity. This study indicated that alkaline stress affected the genes related to stress responses, metabolism, and malate accumulation in the roots of M. crystallinum. [ABSTRACT FROM AUTHOR]

Midvein is an important structure of the upright leaf of rice, and its normal development is essential to the formation of a common plant type of rice (Oryza sativa L.). To reveal the effect of midvein deficiency on photosynthesis-related characteristics, leaf microstructure, and vein characteristics, the photosynthetic features between the midvein-deficient mutant dl-14 and wild-type Huanghuazhan plants were analyzed. The results indicated that the midvein area of the dl-4 mutant lacked large intercellular space and instead it was filled with mesophyll cells. Moreover, the vein density of the dl-14 mutant was significantly higher than that in cv. Huanghuazhan. Chlorophyll (Chl) a, Chl b, and carotenoid content were markedly elevated in dl-14. In terms of photosynthetic characteristics, we observed that under high irradiance and high CO2 concentration, the net photosynthetic rate of dl-14 plants was significantly higher than that of Huanghuazhan plants, but its water use efficiency was significantly lower. In addition, several major photosynthetic parameters, including characteristics of chlorophyll fluorescence (the efficiency of excitation capture of open PS II center, photochemical quenching, effective quantum yield of PS II photochemistry, and electron transfer rate) were significantly higher in dl-14 plants compared to Huanghuazhan plants, but the nonphotochemical quenching of dl-14 mutant was significantly lower than that of Huanghuazhan. These findings indicate that the dl-14 mutant has higher vein density, stronger photon conversion ability, and weaker radiation dissipation ability. This study can provide theoretical support for breeders to use the midvein-deficient mutant. [ABSTRACT FROM AUTHOR]

Midvein is an important structure of the upright leaf of rice, and its normal development is essential to the formation of a common plant type of rice (Oryza sativa L.). To reveal the effect of midvein deficiency on photosynthesis-related characteristics, leaf microstructure, and vein characteristics, the photosynthetic features between the midvein-deficient mutant dl-14 and wild-type Huanghuazhan plants were analyzed. The results indicated that the midvein area of the dl-4 mutant lacked large intercellular space and instead it was filled with mesophyll cells. Moreover, the vein density of the dl-14 mutant was significantly higher than that in cv. Huanghuazhan. Chlorophyll (Chl) a, Chl b, and carotenoid content were markedly elevated in dl-14. In terms of photosynthetic characteristics, we observed that under high irradiance and high CO2 concentration, the net photosynthetic rate of dl-14 plants was significantly higher than that of Huanghuazhan plants, but its water use efficiency was significantly lower. In addition, several major photosynthetic parameters, including characteristics of chlorophyll fluorescence (the efficiency of excitation capture of open PS II center, photochemical quenching, effective quantum yield of PS II photochemistry, and electron transfer rate) were significantly higher in dl-14 plants compared to Huanghuazhan plants, but the nonphotochemical quenching of dl-14 mutant was significantly lower than that of Huanghuazhan. These findings indicate that the dl-14 mutant has higher vein density, stronger photon conversion ability, and weaker radiation dissipation ability. This study can provide theoretical support for breeders to use the midvein-deficient mutant. [ABSTRACT FROM AUTHOR]

Vacuole membrane proteins play a critical role in the regulation of plant physiological processes including normal growth and development, and responses to stresses. The killing me slowly 1 (KMS1) gene that encodes a soluble N-ethylmaleimide-sensitive fusion attachment receptor (SNARE) domain-containing vacuole membrane protein was first reported in Arabidopsis. Currently, the function of KMS1 in other plants under stress is poorly understood. In this study, we report cloning, expression, and characterization of a novel KMS1 gene in alfalfa (Medicago sativa L.), designated MsKMS1 (GenBank accession No. JX467688). The full-length cDNA of MsKMS1 was 1 396 bp and contained a complete open reading frame of 1 257 bp, which encoded a putative protein of 418 amino acids. The BLASTp analysis showed that MsKMS1 shared high amino acid sequence similarities with KMS1 from other plants such as Medicago truncatula (99 %), Cicer arietinum (89 %), Glycine max (77 %), Prunus mume (76 %), Ricinus communis (72 %), Populus euphratica (72 %), Theobroma cacao (72 %), and Arabidopsis thaliana (67 %). Transient transformation of onion (Allium cepa) bulb scale epidermal cells by biolistic bombardment showed that MsKMS1 was localized to the plasma membrane. Quantitative real-time PCR revealed that MsKMS1 expression was upregulated under different abiotic stresses (200 mM NaCl, 20 % (m/v) polyethylene glycol 6000] and 10 mg dm-3 abscisic acid. Transgenic tobacco plants were obtained via Agrobacterium-mediated transformation and treated with 200 mM NaCl. Reverse-transcription PCR data showed that MsKMS1 was successfully transcribed and expressed in the leaves of transgenic plants. The MsKMS1-overexpressors showed a lower malondialdehyde content and maintained a higher relative water content and proline content compared with non-transgenic controls under salt stress. These results indicate that the introduction of the MsKMS1 gene could improve salt stress resistance in tobacco plants. This study reveals the role of MsKMS1 in the regulation of plant responses to abiotic stress and provides evidence for further functional studies of the KMS1 family in alfalfa. [ABSTRACT FROM AUTHOR]

Alkali stress is one of the important factors in restricting agriculture production. Leymus chinensis is constructive halophyte species in alkalized grassland in China. In order to investigate the gene expression response of L. chinensis to alkali stress, we used PacBio technology to obtain reference full-length transcript sequences for transcriptomic analysis of alkali stress response. In order to elucidate the alkali tolerance mechanisms of L. chinensis, we measured the photosynthetic parameters, concentrations of ions and compatible solutes, chloroplast ultrastructure and anatomy of control and stressed plants. Our results showed that L. chinensis shares many alkali-tolerance mechanisms with glycophytes. Higher stability of photosynthetic apparatus under alkali stress may be prominent alkali-tolerance trait of L. chinensis. L. chinensis may have a strong capacity to decline the toxicity of Na+ to organelles and cytoplasmic proteins. Enhanced expression of dehydrin and LEA genes and increased accumulation of carbohydrates may contribute to the development of Na+-specific stress tolerance of L. chinensis under alkali stress. [ABSTRACT FROM AUTHOR]

Uridine diphosphate glucose dehydrogenase (UGDH) is a key enzyme in the hemicellulose and pectin biosynthesis pathway and participates in the regulation of growth and development in plants. In this study, we isolated a BpUGDH gene from paper mulberry (Broussonetia kazinoki × Broussonetia papyifera) and analyzed its function and expression characteristics. The results show that the BpUGDH was expressed in all organs of paper mulberry with a higher expression in stems than in leaves and roots. A pBpUGDH::GUS gene construct was highly expressed in transgenic Arabidopsis thaliana seedlings, and its expression was induced by a low temperature, methyl jasmonate, gibberellin A3, ethylene, and auxin. The overexpression of BpUGDH increased the soluble sugar content, promoted the accumulation of hemicellulose, and enhanced the vegetative growth of transgenic plants. These results provide a basis for regulating the growth and adaptability of paper mulberry and improving its utilization value via genetic modification of the BpUGDH gene. [ABSTRACT FROM AUTHOR]

To investigate the adaptive mechanism of wheat under high light, osmotic stress, and salt stress, redox regulation, and photosynthesis were compared. Under high light, the activities of antioxidant enzymes, except for catalase, significantly increased and then decreased after 1 and 3 h, respectively. Under osmotic stress, antioxidant enzyme activities significantly increased and subsequently declined. Except for superoxide dismutase, salt stress induced a significant increase in all the antioxidant enzyme activities. A significant decrease of D1 protein by high light and osmotic stress, strong photophosphorylation of D1 and D2 under high light and salt stress were observed, while all the stresses induced upregulation of PsbS protein. Eight stress-associated genes (TaMYB73, TaABC1, TaOPR1, TaASR1, TaWRKY44, TaWRKY2, TaWRKY19, and TaCIPK29) showed different expression levels under all the stresses. We conclude that the wheat plant adopted various strategies by regulating the antioxidant system, expression of stress-responsive genes, and photosystems under different abiotic stresses. [ABSTRACT FROM AUTHOR]

Oxybenzone (OBZ), a widely used sunscreen additive, has damaging effects on corals and plants. This study demonstrated that OBZ significantly inhibited photosynthesis and growth of cucumber (Cucumis sativus L.) seedlings. Combined analyses of chlorophyll fluorescence and 820-nm reflection suggested that OBZ severely inhibited photosynthetic electron transport (PET) from QA to cytochrome b6f (Cyt b6f) complex, restricting the reduction of the reaction center in PSI. Separate measurements of PSI and PSII PET in chloroplasts indicated that OBZ inhibited the PET of neither PSII nor PSI, but it severely inhibited the whole linear PET. We thus confirmed that the inhibition of PET by OBZ was due to the inhibition of plastoquinones (PQs) and/or the Cyt b6f complex between PSI and PSII. PET is essential for producing ATP and NADPH used in CO2 assimilation. Therefore, limiting the use of sunscreens containing OBZ is significant in protection of aquatic and terrestrial ecosystems and ensuring the safety of agricultural production. [ABSTRACT FROM AUTHOR]

A pot study was conducted to elucidate morphological and physiological responses of Spatholobus suberectus Dunn accessions to four nitrogen application rates (0, 10, 20, and 30 mmol L-1) and two watering regimes (daily irrigation and irrigation every 10 d for a month). The results showed that water deficit led to marked decreases in leaf water relations and photosynthetic parameters regardless of the N treatments. Under drought conditions, the reductions in net photosynthesis occurred mainly due to stomatal factors. Although the leaf N content and stem mass ratio were positively correlated with N application, other morphological and physiological characteristics were negatively correlated or nonsignificantly correlated with N application under limited water supply. As the root nodules of S. suberectus can provide sufficient N supply, and high N applications made S. suberectus plants more vulnerable to drought stress, we suggest that no N supplement is required for S. suberectus seedlings. [ABSTRACT FROM AUTHOR]

Chlorophytum capense var. medio-pictum is widely used as a houseplant with its central yellowish white stripe in green leaves. This study investigated chlorophyll biosynthesis, and epidermal characteristics in leaf stripes of different color. The results showed that yellowish white leaf stripes (YS) have a lower 5-aminolevulinic acid (ALA) content than that of green stripes. Meanwhile, YS had higher coproporphyrinogen III (Coprogen III) and Mg-protoporphyrin monomethyl ester (Mpe) contents, but the lower content of protoporphyrinogen IX (Proto IX) and protochlorophyllide (Pchlide) compared to green stripes, suggesting that the occurrence of yellowish white stripes may be attributed to the blocked ALA synthesis and the inhibited conversions from Coprogen III to Proto IX and Mpe to Pchlide. In addition, the upper and lower epidermal cells in YS were larger than those in green stripes. The chloroplasts developed normally in the guard cells of the YS epidermis, though almost no chloroplasts were detected in YS mesophyll cells. [ABSTRACT FROM AUTHOR]

Water stress is a key factor limiting sorghum growth and yield potential. This study investigated the changes in morphology, photosynthetic parameters, and fluorescence characteristics of sorghum under drought and waterlogging stress. The results indicated that these two types of water stress limited sorghum growth and led to a decrease in leaf chlorophyll (Chl), especially Chl a, which was accompanied by a decrease in net photosynthetic rate. In addition, under both types of water stress, the light-compensation point (LCP) and light-saturation point (LSP) both decreased, but the effect on these parameters was more obvious under drought. In terms of fluorescence parameters, the initial fluorescence and variable fluorescence increased under drought and waterlogging stress, while the maximum fluorescence did not change significantly, and the electron transport rate, photochemical quenching, and PSII actual quantum yield decreased. In summary, these results suggest that sorghum adapts to drought and waterlogging stress by reducing the leaf Chl a content, reducing LCP and LSP, and changing fluorescence parameters. [ABSTRACT FROM AUTHOR]

Barnyard grass (Echinochloa crus-galli) is a troublesome graminaceous weed infesting rice fields in the Yangtze River Basin, China. However, the effects of barnyard grass on rice root physiology are unclear. In this study, the effects of barnyard grass, planted at different densities (ranging from 2-8 plants m-2), on rice performance were evaluated, including chlorophyll fluorescence parameters, Rubisco activity, root oxidation activity, and the zeatin + zeatin riboside concentration. The results indicated that rice photosynthesis and physiological characteristics decreased as the density of barnyard grass increased. The rice net photosynthetic rate significantly declined and ranged between 17.3-10.5% compared with the control (0 barnyard grass plants m-2). The results showed that rice grain yields decreased to 58% when barnyard grass was planted at a density of 8 plants m-2. We found that barnyard grass can reduce the Rubisco activity, leaf photosynthetic capacity, and energy conversion efficiency in rice, thus resulting in the reduced rice yield. [ABSTRACT FROM AUTHOR]

Currently, the main maize production areas in northeastern China are facing soil fertility loss, which severely affects root growth and limits photosynthesis. It is widely acknowledged that physiological conditions of the root system are closely related to the photosynthetic capacity; therefore, we evaluated whether there are certain differences in root bleeding sap characteristics and photosynthetic capacity between the hybrids and their parents. The results showed that heterosis of the photosynthetic capacity occurred at the milk-ripe stage; however, heterosis of bleeding-sap mass (BSM) and organic biomass occurred during the whole growth period. Photosynthetic rate correlated positively with BSM and the bleeding components; a similar trend was also observed between BSM and bleeding components. These data suggested that appropriate water and fertilizer supply can improve the photosynthesis-related parameters and yield of maize. [ABSTRACT FROM AUTHOR]

Expression quantitative trait loci (eQTL) analyses were applied in order to identify genetic factors that are relevant to the expression of a β-isoform Rubisco activase gene in maize, namely ZmRCAβ, in this study. During two years, a maize recombinant inbred line population was measured for ZmRCAβ expression levels at the grain filling stage. Based on a genetic map containing 916 molecular markers, we detected five eQTLs, namely qRCA2.1 on chromosome 2, and qRCA4.1, qRCA4.2, qRCA4.3, and qRCA4.4 on chromosome 4. These eQTLs explained the phenotypic variation ranging from 6.14% to 7.50% with the logarithm of the odd values ranging from 3.11 to 4.96. Based on the position of the eQTLs and ZmRCAβ on the chromosome, qRCA4.2 was inferred as a cis-eQTL and the remaining as a trans-eQTL, suggesting that a combination of both cis- and trans-acting elements might control ZmRCAβ expression. qRCA4.2, qRCA4.3, and qRCA4.4 were repeatedly detected during two years. [ABSTRACT FROM AUTHOR]

We carried out a field experiment in order to study effects of fertilization in juvenile plants of three coffee ( Coffea arabica) cultivars in Yunnan, SW China. Fertilization treatments included a control without fertilizer (CK), combinations of three NPK fertilization rates [high fertilization (F), medium fertilization (F), and low fertilization (F) with 135, 90, and 45 g per plant per year, respectively], and at two N:PO:KO ratios (R, 1:0.5:0.8; R, 1:0.8:0.5). The growth in juvenile plants was not altered by fertilization, with two clear growth peaks being observed in both the height and stem growth rates (RGRs) throughout a year. Both F and F resulted in significantly higher RGRs in both height and stem diameter compared to F and CK in all three cultivars. At the same fertilization rate, the leaf area, branch number, longest branch length, internode number, and biomass of R were higher than those of R, and P significantly affected the root biomass and root to shoot ratio. Compared to the F treatment, both F and F treatments resulted in higher net photosynthetic rates and stomatal conductance across seasons, and in higher intrinsic water-use efficiency during the dry season and at the middle of the wet season. Photosynthetic nitrogen-use efficiency at R was higher than that at R, but no significant differences were observed between the different fertilization rates. Among the three coffee cultivars, Caturra exhibited the highest height, stem diameter, longest branch length, and internode number. Our results indicated that the optimal N:PO:KO ratio was 1:0.8:0.5 for the juvenile growth of coffee plants. Both F and F could help optimize the growth and photosynthetic rate of coffee plants, but F is suitable for the ecological friendly agriculture and economic sustainability at coffee plantations. [ABSTRACT FROM AUTHOR]

Ca has been considered as a necessary ion for alleviation of stress-induced damages in plants. We investigated effects of exogenous Ca on waterlogging-induced damage to pepper and its underlying mechanisms. Pepper seedlings under stress were treated by spraying of 10 mM CaCl. Applying exogenous Ca increased the biomass of pepper leaves and roots, improved photosynthetic characteristics, membrane permeability, root activity, osmotic substance contents, antioxidant enzyme and alcohol dehydrogenase activities, while it reduced lactate dehydrogenase activity. It maintained hydroxide radical contents and activities of malate dehydrogenase and succinate dehydrogenase relatively high. Our results suggested that applying exogenous Ca could regulate osmotic substance contents, antioxidant system activity, root respiration, and metabolism, and subsequently alleviate waterlogging-induced damages to pepper plants. [ABSTRACT FROM AUTHOR]

Cytochrome P, CYP93A1, is involved in the synthesis of the phytoalexin glyceollin in soybean ( Glycine max L. Merr). The gene encoding CYP93A1 has been used as defense marker in soybean cell cultures, however, little is known regarding how this gene is expressed in the intact plant. To further understand the tissue-specific role of CYP93A1 in soybean defense, we analyzed the expression of this gene in mechanically damaged leaves and stems. In leaves, CYP93A1 was constitutively expressed; its expression did not change in response to mechanical damage. In stems, however, expression of CYP93A1 was induced as quickly as 4 h after mechanical damage and remained upregulated for at least 48 h. The induction of CYP93A1 was associated with the synthesis of glyceollins. In comparison to several other defense-related genes encoding cysteine protease inhibitors L1 and R1 and storage proteins vspA and vspB, CYP93A1 was the most strongly induced by stem wounding. The induction of CYP93A1 was observed only locally, not systemically. Similar stem expression patterns were consistently observed among three different soybean genotypes. The strong induction of CYP93A1 in mechanically damaged stems suggests an important role in the soybean stem defense response; therefore, this study expands the use of CYP93A1 as a defense response marker to stems, not just soybean cell cultures. [ABSTRACT FROM AUTHOR]

During the last century, the world soybean yield has been constantly enhancing at a remarkable rate. Factors limiting the soybean yield may be multiple. It is widely acknowledged that changes of root metabolism can influence aboveground characteristics, such as the seed yield and photosynthesis. In this study, we considered root bleeding sap mass (BSM) and root activity (RA) as indicators of the root growth vigour. We used 27 soybean cultivars, spanning from 1923 to 2009, to evaluate the contribution of root characteristic improvement to efficient photosynthesis and dry matter production. The BSM, RA, net photosynthetic rate ( P), and organ biomass were measured at different growth stages, such as the fourth leaf node, flowering, podding, and seed-filling stage. Our results showed that the soybean cultivars increased their biomass and P thanks to genetic improvement. At the same time, BSM and RA also increased in dependence on a year of cultivar release. However, both P and biomass were positively correlated with root characteristics only at the podding stage. Our data revealed that the improved root characteristic may have contributed to the enhanced photosynthesis, biomass, and yield of soybean cultivars during last 87 years of genetic improvement. We suggest that BSM and RA could be used as important indexes for further practice in soybean production improvement. [ABSTRACT FROM AUTHOR]

To study the effects of application of salicylic acid (SA) on the antioxidant system and photosystem II (PS II) in wheat seedlings we used two different experiments. The first method was carried out by immersing roots in Hoagland's nutrient solution containing 0, 0.25, or 2.5 mM SA, and the second method was performed by spraying two-week-old seedlings with the same SA concentrations. After 24 h, chlorophyll fluorescence, thylakoid membrane proteins, antioxidant enzyme activities, and reactive oxygen species were measured. The low concentration of SA caused a significant increase in the antioxidant enzyme activities. However, the treatment with 2.5 mM SA resulted in an increase in the non-photochemical quenching coefficient and a decrease in the antioxidant enzyme activities, the quantum yield of PS II photochemistry, and the photochemical quenching, especially in the first method of application. All these results indicate that the effects of SA on PS II and the antioxidative defense system were dependent on the concentration used and the method of application. [ABSTRACT FROM AUTHOR]

The GhMYB9 encodes a R2R3 MYB transcription factor in the upland cotton ( Gossypium hirsutum L.) genome. Our studies show that GhMYB9 predominantly expressed in flowers and fibers. To gain a better understanding of its regulatory mechanism, we isolated the 5′-flanking region of GhMYB9 which was 1 487 bp in length. The cis-acting element prediction shows that this region contained the basic structure of the core promoter elements (TATA-box, CAAT-box) and the transcription start site (TSS). Other motifs, such as defense and stress responsiveness (TC-rich repeats), anaerobic induction (ARE), and MYB binding sites involved in drought-inducibility (MBS), were also found. Histochemical assay shows that the GhMYB9 promoter governed β-glucuronidase (GUS) expression mainly in seeds, fibers, and flowers of transgenic cotton. Also, the activity of the promoter was induced by auxin in fibers of transgenic cotton. This is consistent with its transcript abundance in different tissues. A further deletion analysis confirms that a promoter region from -1 231 to -860 was required for auxin response. Our findings provide a useful reference for the understanding of the transcriptional regulation mechanism of the GhMYB9 gene. [ABSTRACT FROM AUTHOR]

There is a great uncertainty about the effect of land use change on grassland ecosystem in the Tibetan Plateau. Net ecosystem carbon exchange (NEE) was measured for native alpine meadow with winter grazing (NAM), abandoned cropland/pasture (APL), perennial Elymus nutans (PEN), and annual oat pasture (AO) on the Tibetan plateau, during the growing seasons in 2009 and 2010 using a transparent chamber technique ( Licor-6400). AO significantly decreased annual average NEE by 21.6, 23.7, and 15.7% compared to PEN, NAM, and APL during the growing season in 2010. Compared to PEN, NAM, and APL, AO significantly decreased average ecosystem respiration (R) by 21.1, 52.3, and 39.3%, respectively, during the growing season in 2009. Soil moisture and total aboveground and belowground biomass together explained 39.6% of NEE variation and 71% in gross primary productivity variation. Soil moisture and belowground biomass explained about 83.1% of the R variation. Our results indicated that it is possible to convert APL to PEN in the region because it could result in a higher NEE together with higher forage production compared to AO. [ABSTRACT FROM AUTHOR]

Pepper is a thermophilous and heliophilic vegetable. In China, pepper is grown in greenhouse during winter and spring under lower temperature and irradiation. In this study, we investigated the effects of low temperature and low irradiance (LTLI) on the physiological characteristics and the expression of related genes in five pepper species, Capsicum annuum L. (CA), C. baccatum L. (CB), C. chinense Jacquin (CC), C. frutescens L. (CF), and C. pubescens Ruiz & Pavon (CP) in order to screen for greenhouse species that is resistant to such adverse conditions. We observed significant reductions not only in photosynthetic pigments and stomatal conductance but also in proline, total soluble sugar, enzyme activity, and root activity; disordered arrangements of leaf palisade and spongy tissues; and first rising and then falling expression of C-repeat binding factor ( CBF3) and cold-regulated genes ( CORc410). These results indicate that pepper is not resistant to LTLI. We also found that CP showed significantly higher photosynthetic activity, more proline and total soluble sugar, higher enzyme activity, higher root activity, higher CBF3 and CORc410 expression levels, more tightly packed leaf palisade and spongy tissues, and thicker bundle sheath than the other four species did under LTLI, while CF exhibited the lowest values for these indicators. It demonstrated significant differences in the ability to resist to LTLI among different species, with CP showing the strongest resistance, followed by CB. Therefore, we recommend the introduction of CP and CB to greenhouse cultivation to further screen for low temperature and low light-resistant pepper varieties to increase pepper production by strengthening intervariety hybridization. [ABSTRACT FROM AUTHOR]