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This research was conducted in Idlib Governorate, located in northwestern Syria, during the years 2021, 2022 and 2023. The two types of wild hawthorn, Monogyna hawthorn (Crataegus monogyna), and Aronia hawthorn (Crataegus azarolus var. aronia) were propagated by seeds and vegetatively. Two types of treatments were used for sexual propagation by seeds, namely soaking with gibberellin at concentrations of 1000 and 2000 ppm and intervals of 24 and 48 hours, and soaking with sulfuric acid at concentrations of 50% and 98% and intervals of one and two hours. The two treatments were followed by warm stratification for two months, followed by cold stratification for 3 months, while the control treatment was subjected to stratification only. Vegetative propagation was done by cuttings that were dipped in several concentrations of IBA, where concentrations of 4000, 6000, and 8000 ppm were used. The results showed that seed propagation achieved better results than vegetative propagation. The treatment of Monogyna seeds with gibberellin at a concentration of 2000 ppm and during the 48-hour soaking period significantly outperformed all other treatments, with a germination rate of 73.33%. The treatment of Monogyna cuttings at a concentration of 8000 ppm of IBA significantly outperformed the rest of the experimental treatments, with a rooting rate of 16.67%. The Monogyna type significantly outperformed the Aronia type in seed germination rate and rooting rate of cuttings, with values of 40 and 20.42% for seed germination and 8.42 and 5.17% for rooting of cuttings for the two types, respectively. Finally, alternating (warm and cold) seed stratification, treatment with gibberellin or sulfuric acid, and the use of seeds stored in the refrigerator for a full year, played an important role in increasing the germination rate of hawthorn seeds. [ABSTRACT FROM AUTHOR]

The yellow (Passiflora edulis) and sweet (Passiflora alata) passion fruit plants hold significant economic importance in tropical fruit cultivation, valued not only for the quality of their fruit but also for their medicinal properties. Conventional propagation through seeds faces challenges due to irregular and slow germination, affecting the time required for seedling formation and the viability and uniformity of plantations. The use of plant growth regulators has been explored as a strategy to overcome these barriers, improving both the rate and uniformity of seed germination. This study aimed to evaluate the influence of seed imbibition with plant growth regulators on the germination and subsequent growth of yellow and sweet passion fruit seedlings. Gibberellic acid (GA3) and GA4+7 combined with 6-benzyladenine (GA4+7+6BA) were applied in five different concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). The experiments were conducted in both laboratory and greenhouse conditions, following a completely randomized design with a 2 × 5 factorial scheme. The varieties tested were 'BRS Mel do Cerrado' for sweet passion fruit and 'IAC-275' for yellow passion fruit. Quantitative parameters, such as germination percentage, germination speed index, fresh and dry biomass of roots and shoots, and enzymatic activity, were assessed. The results indicated that GA3, at higher concentrations, significantly enhanced both germination percentage and speed index in both Passiflora alata and Passiflora edulis when compared to the control. Additionally, seedlings treated with GA3 showed a marked increase in shoot and root biomass, particularly at concentrations of 500 and 750 mg L−1. Enzymatic assays revealed heightened catalase and peroxidase activities in treated seedlings, indicating improved stress tolerance. In contrast, the GA4+7+6BA treatment showed less pronounced effects on seedling growth. Overall, GA3 was more effective in enhancing germination and seedling growth in both species, suggesting its potential application in improving the propagation of passion fruit. [ABSTRACT FROM AUTHOR]

The propagation of citrus seedlings is accomplished through grafting, utilizing seeds for the production of rootstocks. The germination of certain seeds may be low and uneven, complicating the production of high-quality seedlings. The use of plant growth regulators (PGRs) is a viable alternative to improve the quality of seedling production, as these compounds can break dormancy, control the hydrolysis of reserves, induce cell division, and regulate permeability and protein functions. This study aimed to evaluate the germination of seeds and the growth of Rangpur lime (Citrus limonia L. Osbeck) seedlings under the influence of imbibition in solutions of gibberellic acid (GA3) and a combination of GA4+7 + 6Benzyladenine. The experiment was conducted under controlled laboratory and greenhouse conditions, using a completely randomized design in a 2 × 5 factorial scheme, with two types of plant regulators (GA3 and GA4+7 + 6BA) at five concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). Quantitative and qualitative variables were evaluated, ranging from seed germination to seedling development and formation, including germination percentage and speed index, fresh and dry biomass of roots and shoots, enzymatic activity, and gas exchange. The results indicate that GA3 significantly accelerates the germination process of Rangpur lime cv. Santa Cruz seeds and promotes better seedling growth and development, resulting in vigorous seedlings. These findings demonstrate that the application of PGRs, particularly GA3, can substantially enhance the propagation efficiency of citrus rootstocks, offering a practical solution for improving the uniformity and quality of seedling production in commercial settings. [ABSTRACT FROM AUTHOR]

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In the study, the effects of 0, 100, 200 and 400 ppm spray applications of GA3 on root and above-ground parts of 'Jan Reus', 'Bloody Mary' and 'Yokohama' tulip cultivars were determined. According to the results, on the development of plant upper part properties, 200 ppm in 'Jan Reus' and 'Yokohama' and 100 ppm in 'Bloody Mary' were the most effective applications. Again, the least increases in upper part properties were obtained from the control plants in 'Jan Reus' and 'Bloody Mary', and from the 100 ppm application in 'Yokohama'. While 100 ppm was the most effective application in 'Jan Reus' and 'Yokohama' in terms of root development, the effect of the applications in 'Bloody Mary' was lower than the control. The application that least increased root development was determined as 400 ppm in 'Jan Reus' and 200 ppm in 'Bloody Mary' and 'Yokohama'. Root growth was found to be negatively related to GA3 content. High GA3 is thought to negatively affect overall root growth, possibly by suppressing the effect of auxin. It is assumed that GA3 produced by the plant itself may be sufficient for root development or may be effective at much lower dose applications. On the other hand, it has been determined that the effects of GA3 application vary depending on the variety. According to these results, it is recommended to apply it at a dose of 200 ppm to ensure flowering by providing cooling in tulip cultivars and cut flower cultivation. High doses of GA3 are not recommended for root development.

Exogenous gibberellic acid was applied to regulate fruit growth of grapes to acquire high quality seedless berries. The vascular bundles provide the pathway of water and nutrient transport into the fruit and play an important role in berry growth and sugar accumulation. Therefore, changes in berry size and quality are closely related to the structure and function of the vascular tissue. In this study, 10-year-old “Shine Muscat” grape vines were treated with GA3 in grapevine production. Based on previous research and experimental environmental conditions, four treatments were applied: elongating cluster（5 mg L−1 GA3 on Apr. 28）+ seedless（25 mg L−1 GA3 on May. 24）+ expanding（50 mg L−1 GA3 on Jun. 7） (T1), seedless（25 mg L−1 GA3 on May. 24）+ expanding（50 mg L−1 GA3 on Jun. 7） (T2), expanding（50 mg L−1 GA3 on Jun. 7） (T3) and water (CK). Compared to CK, all fruits treated with GA3 had greater berry size. In addition, GA3 treated grapes had greater vascular bundle areas, including the areas of both phloem and xylem, as well as a greater number of vessels compared to control fruit. During the first rapid growth stage, water transport into the grape was rapid and did not differ among treatments. During veraison, the water transport rate among the four treatments differed, and the rank of speed was T2>T3>CK>T1. Therefore, we found that GA3 treatment can significantly promote the differentiation of vascular tissues and improve water transport capacity and phloem sugar unloading; T2 promoted the development of vascular bundles, enhanced water transport speed and phloem sugar unloading of fruit after veraison, and increased berry size.

Plant growth regulators play an essential role in plants' biochemical processes. In this study, foliar spray was applied using three growth regulators, gibberellic acid (GA3), naphthalene acetic acid (NAA), and 6-benzyl amino purine (BAP), to investigate their effects on wheat (Triticum aestivum L.) 'Giza-171' yield traits and grain biochemical constituents, including sugars, carbohydrates and protein. The assessed growth regulators (GA3, NAA, and BAP) were applied at 100 and 150 mg L-1 concentrations. The results indicated significant improvements in wheat grain yield and 1000-grain weight, which increased by 15.40% and 24.78%, respectively, using GA3 at 150 and 100 mg L-1. In addition, the highest contents of protein and carbohydrates were observed with samples treated by the foliar application of NAA at 150 mg L-1 and BAP at 100 mg L-1, respectively. The fat content in wheat grains increased by 1.97% and 2.73% with foliar spray with 150 mg L-1 NAA and 100 mg L-1 BAP, respectively. The lipid profile showed cis-linoleic acid was the primary fatty acid, followed by palmitic acid; the content of linoleic acid slightly increased with GA3 treatment to 50.42%, while palmitic acid significantly increased with 100 mg L-1 NAA. The total saturated and unsaturated fatty acids recorded 33.64% and 66.30%, respectively; the 150 mg L-1 NAA treatment had the lowest saturated fatty acid content. The SDS-PAGE profiles showed that growth regulators significantly enhanced the wheat protein where new bands appeared, especially in 100 mg L-1 GA3 and 100 mg L-1 BAP treatments. The applied growth regulators improved wheat yield, contents of some compounds, and nutritional value. [ABSTRACT FROM AUTHOR]

Fruit drop from pear trees causes serious losses in income. However, the application of plant bio-regulators improves the internal physiology of developing fruit by ensuring that they receive an adequate supply of water, nutrients, and other compounds necessary for their proper growth and development, which leads to improved size, quality, and ultimately better yield in a variety of fruit crops. This study investigated the foliar application of three plant growth regulators: CPPU at 10, 15, and 20 ppm, GA3 at 25, 50, and 75 ppm and NAA at 25, 50, and 75 ppm. The pear trees were sprayed four times: before flowering, full bloom, after three weeks, and after six weeks. The results showed that the spray of GA3 at 50 and 75 ppm gave the highest effect in increasing the shoot length, shoot thickness, leaf area, and leaf total chlorophyll. The spraying of NAA at 50 and 75 ppm was the best treatment in increasing the fruit set percentages, fruit yield, fruit weight, and fruit dimensions as well as the fruit content from soluble solids, and fruit sugars, while they reduced the fruit drop percentages comparing with the other applied treatments.

Paeonia peregrina Mill. is a protected, herbaceous species native to Southeastern Europe and Turkey. Due to its vulnerability, it has to be protected both in its natural habitats and through cultivation. Peonies are known to have a low potential for natural regeneration due to their seed dormancy, low germination rate, and long germination period. In this study, treatments with gibberellic acid (GA3 150, 200, 250, 300, and 350 mg L−1 GA3) and warm (at 20/16 °C day/night regime) and cold stratification (at 4 °C) were used to accelerate dormancy release and increase the germination rate. The seeds of P. peregrina from four natural habitats in Serbia and the Institute's collection were collected and analyzed. They showed an underdeveloped embryo that needs to grow inside the seed before it can germinate. The application of GA3 accelerated each stage of germination (seed coat rapturing, hypocotyl dormancy release, and epicotyl dormancy release) for approximately 10 days compared to the control. It was also found that two-day imbibition with 200 mg L−1 GA3 significantly accelerated and equalized germination. Higher GA3 concentrations had a more pronounced impact on each stage but also resulted in greater seed infection after the seed coat rupture, elongated and weak seedlings, while lower concentrations did not result in obtaining uniform seedlings. There were no significant differences observed between localities. Restoring P. peregrina through seeds and nursery-produced plants is crucial for conserving the genetic diversity of the tested species. [ABSTRACT FROM AUTHOR]

Introduction: Phosphorus nutrition and hormone concentration both affect crop yield formation. Ascertaining the interaction of phosphorus and GA3 has a synergistic effect on the grain yield and phosphorus utilization efficiency of oilseed flax in dryland. It is extremely important for improving grain yield and phosphorus utilization efficiency. Methods: A field experiment was conducted in 2019 and 2020 at the Dingxi Oil Crops Test Station to investigated the effects of phosphorus, gibberellin (GA3), and their interaction on the grain yield and phosphorus-utilization efficiency of oilseed flax plants. Phosphorus fertilizerwas applied at three levels (0, 67.5, 135 kg P2O5·ha-1) and GA3 was also sprayed at three concentrations (0, 15, and 30 mg·L-1). Results: The results showed that application of 67.5 kg P2O5·ha-1 reduced leaves acid phosphatase (ACPase) activity, but increased phosphorus accumulation throughout the growth period, the 1000-kernel weight (TKW), and the number of grains per capsule. Spraying GA3 significantly increased the leaves ACPase activity, phosphorus accumulation after anthesis and its contribution to grain, phosphorus-utilization efficiency, the number of capsules per plant, and TKW. The phosphorus accumulation at the anthesis, kernel, and maturity stages under the treatment of fertilizing 67.5 kg P2O5·ha-1 and spraying 30 mg·L-1 GA3 were increased by 56.06%, 73.51%, and 62.17%, respectively, compared with the control (no phosphorus, no GA3). And the phosphorus accumulation after anthesis and its contribution to grain also increased. 67.5 kg P2O5·ha-1 combined with 30 mg·L-1 GA3 and 135 kg P2O5·ha-1 combined with 15 mg·L-1 GA3 both significantly increased grain yield of oilseed flax, reaching 1696 kg·ha-1 and 1716 kg·ha-1 across two years, respectively. And there was no significant difference between them. However, the former treatment significant increased the apparent utilization rate, agronomic utilization rate, and partial productivity of phosphorus. The interaction between phosphorus and GA3 was significant for grain yield. Conclusion: Therefore, the application of 67.5 kg P2O5·ha-1 in combination with 30 mg·L-1 GA3 is an effective fertilization approach for enhancing oilseed flax growth and grain yield in the experiment region and other similar areas. [ABSTRACT FROM AUTHOR]

Fruit drop from pear trees causes serious losses in income. However, the application of plant bio-regulators improves the internal physiology of developing fruit by ensuring that they receive an adequate supply of water, nutrients, and other compounds necessary for their proper growth and development, which leads to improved size, quality, and ultimately better yield in a variety of fruit crops. This study investigated the foliar application of three plant growth regulators: CPPU at 10, 15, and 20 ppm, GA3 at 25, 50, and 75 ppm and NAA at 25, 50, and 75 ppm. The pear trees were sprayed four times: before flowering, full bloom, after three weeks, and after six weeks. The results showed that the spray of GA3 at 50 and 75 ppm gave the highest effect in increasing the shoot length, shoot thickness, leaf area, and leaf total chlorophyll. The spraying of NAA at 50 and 75 ppm was the best treatment in increasing the fruit set percentages, fruit yield, fruit weight, and fruit dimensions as well as the fruit content from soluble solids, and fruit sugars, while they reduced the fruit drop percentages comparing with the other applied treatments. [ABSTRACT FROM AUTHOR]

In nature, plants constantly fight against the negative effects of biotic and abiotic stress factors. Salinity encountered in agricultural areas in the world and in our country is one of the most important factors that negatively affects sustainable agriculture. This study was carried out to investigate the effects of Gibberellic Acid (GA3) and Glycine Betaine (GB) applied as pre-treatment to sunflower seeds under salt stress conditions on germination and seedling development. In the experiment, the seeds were pre-treated with four different concentrations of GA3 and GB (0, 15, 30, 45 mg/l) before planting, and then four different salt (Na+Cl-) concentrations (0, 6, 9, 12 dS/m) was put into salt stress application. The experiment was set up with 3 replications according to the Randomized Plot Factorial Trial Design. In the study, germination rate, germination power, seedling length, root length, seedling fresh weight, root fresh weight characteristics and enzyme activities such as CAT, SOD and POD were examined. In the experiment, parallel to the increase in salinity stress, decreases in germination rate and germination power and negative effects on other seedling characteristics were observed. According to the results obtained, positive results were observed for germination and seedling characteristics at 6 dS/m salt stress in 30 and 45 mg/l GB and GA3 applications. As a result, it was concluded that Glycine Betaine applications to sunflower seeds as an alternative to plant regulator groups under salt stress conditions will be beneficial in production. [ABSTRACT FROM AUTHOR]

The present experiment was conducted during October, 2022 to March, 2023 at Horticulture Garden, Department of Fruit Science of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, U.P, India. The experiment was layout in RBD with three replicates of each treatment. Total 10 treatments including one control viz., GA3 15 ppm, GA3 20 ppm, GA3 25 ppm, GA3 30 ppm, Urea 2%, GA3 15 ppm and urea 2%, GA3 20 ppm and urea 2%, GA3 25 ppm and urea 2%, GA3 30 ppm and urea 2% and Control i.e., water spray. The present investigation, it is reported that the application of GA3 30 ppm and Urea 2% with significantly increased initial fruit set (169), fruit retention (84.22%) and decreased fruit drop (84.22%), increased fruit weight (15.44 g), pulp weight (14.43 g), fruit length (4.52 cm), diameter (2.99 cm), volume (16.80 cc) and yield (31.50 kg) branch-1 and minimum stone weight (1.01 g), pulp: stone ratio (14.29) and quality parameters like; TSS (15.30 °Brix), ascorbic acid (99.25 mg) 100 g-1 of fruit pulp and total sugars (9.99%) and decreased titratable acidity (0.10%) content. Hence, plants treated with GA3 30 ppm and urea 2% can further be used to improve the fruiting, overall yield improvement, and quality characteristics of Banarasi Karaka cultivar of ber. [ABSTRACT FROM AUTHOR]

Symplocos paniculata are reported to exhibit seed dormancy, which impedes its cultivation and widespread adoption. In this study, a comprehensive method was established to overcome seed dormancy by subjecting seeds to scarification in 98% H2SO4 for 10 min, followed by 1000 mg·L−1 GA3 soaking for 48 h and stratification at 4 °C for 100 days. The seed germination percentage has increased significantly, to a peak of 42.67%, though the seeds could not germinate timely by NaOH scarification. Additionally, the dynamic changes of key stored substances (proteins, soluble sugars, starches, and fats), associated enzyme activities (amylases, peroxidase, and catalase), and endogenous hormones (abscisic acid, gibberellic acid, and indole-3-acetic acid) in seeds were investigated. The results demonstrated a continuous degradation of starch and fat in S. paniculata seeds, while the levels of protein and soluble sugar exhibited fluctuations, which probably facilitated seed dormancy breaking through energy supply and transformation. The enzymatic activities underwent rapid changes, accompanied by a gradual decrease in ABA content within the seeds with increasing stratification time. Notably, GA3, GA3/ABA, and (GA3 + IAA)/ABA showed significant increases, indicating their positive regulatory roles in seed germination. This study clarified the dormancy mechanism and established an effective method for the release dormancy of S. paniculata seeds. [ABSTRACT FROM AUTHOR]

The viability status of every accession stored in a seed bank is essential for effective germplasm conservation, and it is often assessed through germination tests. However, dormancy can hamper this process. Currently, no dormancy-breaking protocols exist for buckwheat (Fagopyrum esculentum Moench) seeds, which exhibit physiological dormancy. In the present study, using phytohormones and chemicals, namely, gibberellic acid (GA3), KNO3, and H2O2, we identified effective seed dormancy-breaking protocols. Buckwheat seeds exhibited a high degree of dormancy, with only 21% of seeds having germinated. Treatment with KNO3 (0.1%, 0.2%, or 0.4%) and H2O2 (5, 10, or 20 mM) significantly improved seed germination and the dormancy index, and decreased the time to 50% germination and mean germination time. Furthermore, treatment with 200-ppm GA3 improved seedling length by 55%. Moreover, treatments with 20-mM-H2O2 and 0.4%-KNO3 improved seed vigor indices by 305% and 260%, respectively. Compared with the control, α-amylase activity was higher for all seed treatment groups. The groups treated with both 0.4%-KNO3 and 20-mM-H2O2 had the highest α-amylase activity. Thus, treatment with KNO3 (0.1%, 0.2%, or 0.4%) or H2O2 (5, 10, or 20 mM) can be incorporated as a dormancy-breaking protocol for seed testing and germplasm evaluation of buckwheat seeds with physiological seed dormancy. [ABSTRACT FROM AUTHOR]

Fruit shape is one of the important traits for quality evaluation, classification, and market grading of horticultural crops. In order to explore the genes regulating pear fruit shape formation, pear varieties 'Huangguan' and 'Korla Fragrant Pear' with significant differences in fruit shape were selected as experimental materials. Through morphological observation, measurement of fruit longitudinal diameter and fruit transverse diameter, and fruit shape index analysis of the pear fruit growth and development period, the formation of pear fruit shape during the young fruit period was preliminarily determined. By analyzing the transcriptome data of 'Huangguan' and 'Korla Fragrant Pear' at the young fruit stage, 8993 differentially expressed genes were obtained, and the majority of the genes were annotated to the plant hormone signaling pathway, among which gibberellin-related genes accounted for 13.4%. Spraying GA3 at the full-bloom stage can significantly prolong the shape of oriental pear. The results of qRT-PCR showed that the expression level of the gibberellin metabolic pathway gene PbGA2ox11 in 'Huangguan' was significantly higher than that in 'Korla Fragrant Pear'. GA3 treatment inhibited the expression of this gene in 'Korla Fragrant Pear', while PP333 promoted the expression. It was speculated that PbGA2ox11 was most likely to regulate the shape of pear fruit by regulating gibberellin metabolism. This study provides a new method for studying fruit shape via the analysis of the gibberellin synthesis metabolic pathway, new resources for the rational use of plant growth regulators, and theoretical and technical support for cultivating excellent fruit shape. [ABSTRACT FROM AUTHOR]

GA3 is a common plant growth regulator used in production that can accelerate plant metabolism and significantly enhance the plant growth rate. We investigated the effects of exogenous GA3 on the physiological and biochemical indexes of Aglaonema under drought treatment. The effects of exogenous GA3 on the plant height, leaf blight rate, antioxidant enzyme activity, leaf pigment, and malondialdehyde content of Aglaonema were evaluated using Aglaonema ‘Red Ruyi’ as the test material and simulating natural drought treatment in nutrient soil pots. The spraying of exogenous GA3 significantly increased superoxide dismutase and peroxidase enzyme activities, promoted the accumulation of soluble sugars, reduced the accumulation of malondialdehyde, and slowed the decline of chlorophyll and carotenoids, which had good effects such as the reduction of the leaf wilting rate and increase in the plant height as well as the maintenance of the plant shape to maintain the ornamental appearance. The growth indexes such as plant height and wilting rate were mainly influenced by the changes of the leaf pigment and physiological and biochemical indexes of malondialdehyde.

Abstract [Objective] The study aims to identify the NAC transcription factor genes CsNAC79 and Cs- NAC9 in tea plants and analyze their expression patterns under drought, salt, high temperature, and low temperature stresses as well as ABA and GA3 treatments in order to provide references for functional analysis of CsNAC79 and CsNAC9. [Methods] CsNAC79 and CsNAC9 were amplified by RT-PCR from tea plant ‘Longjing 43’ and analyzed by bioinformatics. The expression of CsNAC79 and CsNAC9 under abiotic stresses in tea plants was analyzed by qRT-PCR. [Results] (1) CsNAC79 and CsNAC9 encoded 409 and 282 amino acids, respectively, and contain the conserved NAM domain of the NAC family at 15-150 amino acids and 11-134 amino acids, respectively. (2) CsNAC79 protein was closely related to Actinidia chinensis, Diospyros kaki, and Cynara scolymus, while CsNAC9 protein was closely related to Amygdalus persica, Litchi chinensis, and Durio zibethinus. Both of the NAC transcription factors were hydrophilic proteins without signal peptides and transmembrane structures. The promoter regions of CsNAC79 and CsNAC9 contained abiotic stress- responsive elements. Protein structure analysis showed that Cs- NAC79 and CsNAC9 proteins were mainly composed of random coils and α-helixes. (3) Expression analysis showed that CsNAC79 and CsNAC9 genes were up-regulated under different abiotic stresses. [Conclusion] The CsNAC79 and CsNAC9 genes in tea plants responded to various abiotic stresses.

This study was conducted in 2017 under greenhouse conditions using selected four different potato clones to determine the effects of different doses of GA3 and arbuscular mycorrhizal fungus on mini tuber production. The research, carried out in a randomized complete block design with three replications, applied GA3 doses of 0, 5, 10, and 15 ppm, and mycorrhizal inoculat doses of 0, 500, 1250, and 2000 mg/100 tubers. Parameters including emergence time, plant height, main stem number, tuber number, average tuber weight, tuber size distribution (>45 mm, 28-45 mm,

This study was conducted during growing season (2022), in the nursery of the Horticulture Department, College of Agricultural Engineering Science, University of Duhok, Kurdistan region, Iraq, in summel district, situated at western of Duhok city (8 km from Duhok city center). The study consisted the effect of spray with different concentrations of IBA (0, 1000 and 1500mgl-1), GA3 (0, 750 and 1500mg L-1 ) and Nutri green (0 ,4 and 8mL.l) on some vegetative growth characteristics of almond (Prunus Amygdalus) seedling. The superior results indicated the following: seedling spray with IBA concentrations significantly gave the best increase length of shoots, leaf area, increase number of shoots, height of seedling, also seedling spray with GA3 concentrations effect significantly gave the best result of increase length of shoots, leaf area, decrease number of shoots, increase height of seedling, whereas seedling spray with Nutri green concentrations significantly gave the best result only of increase number of shoots.

The roots, stems, leaves, and seeds of Eucommia ulmoides contain a large amount of trans-polyisoprene (also known as Eu-rubber), which is considered to be an important laticiferous plant with valuable industrial applications. Eu-rubber used in industry is mainly extracted from leaves. Therefore, it is of great significance to identify genes related to regulating the leaf size of E. ulmoides. Plant growth-regulating factors (GRFs) play important roles in regulating leaf size, and their functions are highly conserved across different plant species. However, there have been very limited reports on EuGRFs until now. In this study, eight canonical EuGRFs with both QLQ and WRC domains and two putative eul-miR396s were identified in the chromosome-level genome of E. ulmoides. It is found that, unlike AtGRFs, all EuGRFs contain the miR396s binding site in the terminal of WRC domains. These EuGRFs were distributed on six chromosomes in the genome of E. ulmoides. Collinearity analysis of the E. ulmoides genome revealed that EuGRF1 and EuGRF3 exhibit collinear relationships with EuGRF2, suggesting that those three genes may have emerged via gene replication events. The collinear relationship between EuGRFs, AtGRFs, and OsGRFs showed that EuGRF5 and EuGRF8 had no collinear members in Arabidopsis and rice. Almost all EuGRFs show a higher expression level in growing and developing tissues, and most EuGRF promoters process phytohormone-response and stress-induced cis-elements. Moreover, we found the expression of EuGRFs was significantly induced by gibberellins (GA3) in three hours, and the height of E. ulmoides seedlings was significantly increased one week after GA3 treatment. The findings in this study provide potential candidate genes for further research and lay the foundation for further exploring the molecular mechanism underlying E. ulmoides development in response to GA3. [ABSTRACT FROM AUTHOR]

Background: Homeodomain-leucine ZIPper (HD-ZIP) transcription factors play crucial roles in plant growth, development, and stress responses. The HD-ZIP family is categorised into four groups (HD-ZIP I-IV). While extensive genome-wide studies have been conducted on the HD-ZIP I, III, and IV subfamily in Nicotiana tabacum (tobacco), comprehensive reports on the HD-ZIP II subfamily genes are limited. Methods: Bioinformatics resources and tools were utilised to analyse molecular characteristics, phylogenetic homology, and protein interactions. Expression pattern analyses in various tissues and the relative expression of NtHD-ZIP II genes under drought and GA3 treatment were assessed by qRT-PCR. Results: In this study, 24 HD-ZIP II members were systematically identified and categorised into seven independent clades through phylogenetic analysis involving tobacco and other plant species. We found that 19 NtHD-ZIP II genes exhibited tissue-specific expression. The transcripts of NtHD-ZIPII3, 4, 14, 23, 24 were notably induced under the drought treatments, while those of NtHD-ZIPII7, 11, 12, 20 were suppressed. Furthermore, NtHD-ZIPII15 transcripts decreased following GA3 treatment, whereas the transcripts of NtHD-ZIPII7, 8, 11, 12 were induced after GA3 treatment. Notably, an increase in trichomes was observed in tobacco leaves treated with GA3 and subjected to drought. Conclusions: The expression levels of some HD-ZIP II genes were altered, and an increase in glandular trichomes was induced under GA3 and drought treatments in tobacco. Overall, our findings provide insights into the expression patterns of NtHD-ZIP II genes and will facilitate their functional characterisation in future studies. Highlights: Genome-Wide Identification and Expression Analysis of 24 HD-ZIP II Subfamily Genes in Nicotiana tabacum Including, Differential Expression in Leaves Under Drought and GA3 Stress as Assessed by qRT-PCR. [ABSTRACT FROM AUTHOR]

Purpose. Juniper (Juniperus procera) is a common forest tree species in Saudi Arabia. The decline in many populations of J. procera in Saudi Arabia is mainly due to seed dormancy and loss of natural regeneration. This study assessed the effects of chemical and hormonal treatments on seed germination and seedling growth in juniper plants. Methods. The seeds were subjected to either chemical scarification with 90% sulfuric acid and 20% acetic acid for 6 min or hormonal treatment by seed soaking in two concentrations (50 and 100 ppm) of three growth regulators, namely, indole acetic acid (IAA), gibberellins (GA3), and kinetin, for 72 h. A control group without any seed treatment was also prepared. The experiments were performed in an incubator maintained at room temperature and under a light and dark period of 12 h for 6 w. The germinated seeds for each treatment were counted and removed from the dishes. The selected germinated seeds from different treatments were planted in a greenhouse and irrigated with tap water for another 6 weeks. The hormone-treated seedlings were sprayed with their corresponding hormone concentrations 1 w after planting. Results. The highest percentage of seed germination was significantly recorded after seed soaking in 50 ppm GA3, whereas treatment with IAA (100 ppm) resulted in the best seedling growth. Seedlings treated with the three phytohormones showed a significant increase in photosynthetic pigments, total soluble sugars, proteins, percentage of oil, IAA, GA3, and kinetin contents of juniper seedlings compared with the control value, whereas abscisic acid content was decreased compared with chemical treatments. Conclusion. The investigated different treatments had an effective role in breaking seed dormancy and improving seedling growth of J. procera, which is facing a notable decline in its population worldwide. Moreover, such an effect was more pronounced in the three phytohormones that succeeded in breaking dormancy and growth of the Juniperus plant than in the other treatments. [ABSTRACT FROM AUTHOR]

Water deficit (WD) promotes great losses in agriculture, and the development of new sustainable technologies to mitigate the effects of this stress on plants is essential. This study aimed to evaluate the morphophysiological and biochemical alterations induced by the priming of tomato seeds with different formulations in plants under field capacity and WD conditions. In the first experiment, the treatments consisted of nanoparticles of alginate/chitosan and chitosan/tripolyphosphate containing gibberellic acid (GA3) in different concentrations (0.5, 5, and 50 µg mL−1 GA3), in addition to control with deionized water. The alginate/chitosan (5 µg mL−1 GA3) provided the greatest gains in plant growth under field capacity. In addition, under WD this treatment reduced damage to photosystem II (−14%), stomatal conductance (−13%), and water loss (−38%) and increased the instantaneous carboxylation efficiency (+24%) and intrinsic water use efficiency (+12%). In the second experiment, the treatments were alginate/chitosan nanoparticles containing GA3 (NPGA3 5 µg mL−1), free GA3 (GA3 5 µg mL−1), nanoparticles without GA3 (NP), deionized water (WATER), and non-primed seeds (CONT). Under WD, GA3 and CONT maintained plant growth and lost water rapidly, reducing stomatal conductance (−87%) and net photosynthesis (−69%). In contrast, NPGA3 decreased leaf area (−44%) and increased root-to-shoot ratio (+39%) when compared to GA3, reducing water loss (−28%). Activation of protective mechanisms (e.g., superoxide dismutase and catalase activities) by WATER, NPGA3, and NP treatments also resulted in lower susceptibility to WD compared to CONT and GA3. The results highlight the positive effect of seed priming on plant response to WD, which was enhanced by the use of nanoencapsulated GA3. [ABSTRACT FROM AUTHOR]

The present study was conducted at the instructional cum research farm of the Department of Plantation Crops and Processing of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, India during rabi season for consecutive two years (October-2019 to March-2020 and October-2020 to march-2021) to investigate the "Effect of Different Plant Growth Regulators on Quality attributes of Garlic (Allium sativum L.)" with various growth regulators (GA3 @ 50 ppm, GA3 @ 100 ppm, GA3 @ 150 ppm, NAA @ 50 ppm, NAA @ 100 ppm, NAA @ 200 ppm, Kinetin @ 10 ppm, Kinetin @ 20 ppm, Kinetin @ 40 ppm and Control (Distilled water). In view of, effect of different plant growth regulators on quality attributes has observed significant variation. Results pertaining to total soluble solids, significantly highest TSS recorded under GA3 @100 ppm treated plots (32.10 °Brix), however, dry matter content of bulb was highest at GA3 @ 50 ppm (33.63%). Interestingly, highest oleoresin content of the bulb was also reported from the GA3 @ 50 ppm treated plots (0.24 g) with lowest physiological loss of bulb weight (7.04%). The control plots treated with distilled water was produced qualitatively inferior bulbs. The aim of the study provided valuable results to determine the potential growth regulator for enhancing post-harvest quality attribute of garlic by employing methodology of Randomized Block Design comprising of three replications with ten treatments. Based on the current experimental results, it may be concluded that foliar application of GA3 @ 50 ppm proved the best over other plant growth regulators. [ABSTRACT FROM AUTHOR]

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Gibberellic acid (GA3) is a natural hormone present in some plants used in agricultural formulations as a growth regulator. Currently, its production on an industrial scale is performed by submerged fermentation using the fungus Gibberella fujikuroi, which is associated with low yields, leaving the purification stages with high costs. An alternative is solid-state fermentation (SSF), which makes it possible to obtain higher concentrations of product using low-cost substrates, such as agroindustrial by-products. This research investigated the use of raw rice bran (RRB) and barley malt residue (BMR) as substrates for GA3 production by the fungus Gibberella fujikuroi. Through two statistical designs, the effect of moisture (50 to 70 wt.%) and medium composition (RRB content between 30 and 70 wt.% to a mass ratio between RRB and BMR) was first evaluated. Using the best conditions previously obtained, the effect of adding glucose (carbon source, between 0 and 80 g·L−1) and ammonium nitrate—NH4NO3—(nitrogen source, between 0 and 5 g·L−1) on GA3 productivity was analyzed. The best yield was obtained using 30 wt.% RRB and 70 wt.% BMR for a medium with 70 wt.% of moisture after 7 days of process. It was also found that higher concentrations of NH4NO3 favor the GA3 formation for intermediate values of glucose content (40 g·L−1). Finally, a kinetic investigation showed an increasing behavior in the GA3 production (10.1 g·kg of substrate−1 was obtained), with a peak on the seventh day and subsequent tendency to stabilization. [ABSTRACT FROM AUTHOR]

IntroductionPhosphorus nutrition and hormone concentration both affect crop yield formation. Ascertaining the interaction of phosphorus and GA3 has a synergistic effect on the grain yield and phosphorus utilization efficiency of oilseed flax in dryland. It is extremely important for improving grain yield and phosphorus utilization efficiency.MethodsA field experiment was conducted in 2019 and 2020 at the Dingxi Oil Crops Test Station to investigated the effects of phosphorus, gibberellin (GA3), and their interaction on the grain yield and phosphorus-utilization efficiency of oilseed flax plants. Phosphorus fertilizer was applied at three levels (0, 67.5, 135 kg P2O5·ha-1) and GA3 was also sprayed at three concentrations (0, 15, and 30 mg·L-1).ResultsThe results showed that application of 67.5 kg P2O5·ha-1 reduced leaves acid phosphatase (ACPase) activity, but increased phosphorus accumulation throughout the growth period, the 1000-kernel weight (TKW), and the number of grains per capsule. Spraying GA3 significantly increased the leaves ACPase activity, phosphorus accumulation after anthesis and its contribution to grain, phosphorus-utilization efficiency, the number of capsules per plant, and TKW. The phosphorus accumulation at the anthesis, kernel, and maturity stages under the treatment of fertilizing 67.5 kg P2O5·ha-1 and spraying 30 mg·L-1 GA3 were increased by 56.06%, 73.51%, and 62.17%, respectively, compared with the control (no phosphorus, no GA3). And the phosphorus accumulation after anthesis and its contribution to grain also increased. 67.5 kg P2O5·ha-1 combined with 30 mg·L-1 GA3 and 135 kg P2O5·ha-1 combined with 15 mg·L-1 GA3 both significantly increased grain yield of oilseed flax, reaching 1696 kg·ha-1 and 1716 kg·ha-1 across two years, respectively. And there was no significant difference between them. However, the former treatment significant increased the apparent utilization rate, agronomic utilization rate, and partial productivity of phosphorus. The interaction between phosphorus and GA3 was significant for grain yield.ConclusionTherefore, the application of 67.5 kg P2O5·ha-1 in combination with 30 mg·L-1 GA3 is an effective fertilization approach for enhancing oilseed flax growth and grain yield in the experiment region and other similar areas.

The yellow (Passiflora edulis) and sweet (Passiflora alata) passion fruit plants hold significant economic importance in tropical fruit cultivation, valued not only for the quality of their fruit but also for their medicinal properties. Conventional propagation through seeds faces challenges due to irregular and slow germination, affecting the time required for seedling formation and the viability and uniformity of plantations. The use of plant growth regulators has been explored as a strategy to overcome these barriers, improving both the rate and uniformity of seed germination. This study aimed to evaluate the influence of seed imbibition with plant growth regulators on the germination and subsequent growth of yellow and sweet passion fruit seedlings. Gibberellic acid (GA3) and GA4+7 combined with 6-benzyladenine (GA4+7+6BA) were applied in five different concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). The experiments were conducted in both laboratory and greenhouse conditions, following a completely randomized design with a 2 × 5 factorial scheme. The varieties tested were ‘BRS Mel do Cerrado’ for sweet passion fruit and ‘IAC-275’ for yellow passion fruit. Quantitative parameters, such as germination percentage, germination speed index, fresh and dry biomass of roots and shoots, and enzymatic activity, were assessed. The results indicated that GA3, at higher concentrations, significantly enhanced both germination percentage and speed index in both Passiflora alata and Passiflora edulis when compared to the control. Additionally, seedlings treated with GA3 showed a marked increase in shoot and root biomass, particularly at concentrations of 500 and 750 mg L−1. Enzymatic assays revealed heightened catalase and peroxidase activities in treated seedlings, indicating improved stress tolerance. In contrast, the GA4+7+6BA treatment showed less pronounced effects on seedling growth. Overall, GA3 was more effective in enhancing germination and seedling growth in both species, suggesting its potential application in improving the propagation of passion fruit.

The propagation of citrus seedlings is accomplished through grafting, utilizing seeds for the production of rootstocks. The germination of certain seeds may be low and uneven, complicating the production of high-quality seedlings. The use of plant growth regulators (PGRs) is a viable alternative to improve the quality of seedling production, as these compounds can break dormancy, control the hydrolysis of reserves, induce cell division, and regulate permeability and protein functions. This study aimed to evaluate the germination of seeds and the growth of Rangpur lime (Citrus limonia L. Osbeck) seedlings under the influence of imbibition in solutions of gibberellic acid (GA3) and a combination of GA4+7 + 6Benzyladenine. The experiment was conducted under controlled laboratory and greenhouse conditions, using a completely randomized design in a 2 × 5 factorial scheme, with two types of plant regulators (GA3 and GA4+7 + 6BA) at five concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). Quantitative and qualitative variables were evaluated, ranging from seed germination to seedling development and formation, including germination percentage and speed index, fresh and dry biomass of roots and shoots, enzymatic activity, and gas exchange. The results indicate that GA3 significantly accelerates the germination process of Rangpur lime cv. Santa Cruz seeds and promotes better seedling growth and development, resulting in vigorous seedlings. These findings demonstrate that the application of PGRs, particularly GA3, can substantially enhance the propagation efficiency of citrus rootstocks, offering a practical solution for improving the uniformity and quality of seedling production in commercial settings.

The fresh edible jujube variety Yunmi' selected in Beijing was used as the test material, and various treatments such as ring strip- ping of the main stem, gibberellin spray, and ring stripping of the main stem+gibberellin spray were applied during the blooming period to study their effects on fruit set rate, growth, and fruit development. The results showed that the effects of three concentrations of gibberellin treatments on the fruit set showed inverse results, while the decreasing width of ring stripping could increase fruit set rate, but conversely could increase fruit weight per fruit. The treatment of trunk ring stripping+gibberellin spray not only improved fruit quality, but also increased fruit shape index, improved appearance index, and increased fruit set rate. Therefore, the treatment of 2 mm+10 mg/L ring stripping of the main stem+gibberellin spray is an effective method to improve the yield and quality of the Yunmi' jujube fruit. [ABSTRACT FROM AUTHOR]

The GRAS (GAI\RGA\SCL) gene family encodes plant-specific transcription factors that play crucial roles in plant growth and development, stress tolerance, and hormone network regulation. Plant dwarfing symptom is mainly regulated by DELLA proteins of the GRAS gene subfamily. In this study, the association between the GRAS gene family and Paulownia witches' broom (PaWB) was investigated. A total of 79 PfGRAS genes were identified using bioinformatics methods and categorized into 11 groups based on amino acid sequences. Tandem duplication and fragment duplication were found to be the main modes of amplification of the PfGRAS gene family. Gene structure analysis showed that more than 72.1% of the PfGRASs had no introns. The genes PfGRAS12/18/58 also contained unique DELLA structural domains; only PfGRAS12, which showed significant response to PaWB phytoplasma infection in stems, showed significant tissue specificity and responded to gibberellin (GA3) in PaWB-infected plants. We found that the internodes were significantly elongated under 100 µmol·L−1 GA3 treatment for 30 days. The subcellular localization analysis indicated that PfGRAS12 is located in the nucleus and cell membrane. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays confirmed that PfGRAS12 interacted with PfJAZ3 in the nucleus. Our results will lay a foundation for further research on the functions of the PfGRAS gene family and for genetic improvement and breeding of PaWB-resistant trees. [ABSTRACT FROM AUTHOR]

Camellia perpetua has the excellent characteristic of flowering multiple times throughout the year, which is of great importance to solve the problem of "short flowering period" and "low fresh flower yield" in the yellow Camellia industry at present. Observations of flowering phenology have demonstrated that most floral buds of C. perpetua were formed by the differentiation of axillary buds in the scales at the base of the terminal buds of annual branches. However, the molecular mechanism of flowering in C. perpetua is still unclear. In this study, we conducted a comparative transcriptomic study of the terminal buds and their basal flower buds in March (spring) and September (autumn) using RNA-seq and found that a total of 11,067 genes were significantly differentially expressed in these two periods. We identified 27 genes related to gibberellin acid (GA) synthesis, catabolism, and signal transduction during floral bud differentiation. However, treatment of the terminal buds and axillary buds of C. perpetua on annual branch with GA3 did not induce floral buds at the reproductive growth season (in August) but promoted shoot sprouting. Moreover, 203 flowering genes were identified from the C. perpetua transcriptome library through homology alignment, including flowering integrators LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO), as well as MADS-box, SQUAMOSA PROMOTER BINDING PROTEIN-box (SBP-box), and TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) genes, which were specifically upregulated in floral buds and were likely involved in flowering in C. perpetua. The floral inhibitor CperTFL1b was identified and cloned from C. perpetua, and its expression level was specifically regulated in terminal buds in autumn. Ectopic overexpression of CperTFL1b delayed flowering time and produced abnormal inflorescence and floral organs in Arabidopsis, suggesting that CperTFL1b inhibits flowering. In conclusion, this study deepens our understanding of the molecular mechanism of blooms throughout the year in C. perpetua and provides a helpful reference for cultivating new varieties of yellow Camellia with improved flowering traits. [ABSTRACT FROM AUTHOR]

The seeds of Tilia miqueliana Maxim. exhibit deep dormancy, which is categorized as combinational dormancy. This study utilized a comprehensive treatment involving magnetic fields, gibberellin (GA3), and cold stratification to promote the release of seed physiological dormancy and enhance germination rates. After being soaked in 98% H2SO4 for 15 min, mature seeds of Tilia were exposed to magnetic field treatments (150 MT, 250 MT) for different durations (25 min, 45 min, 65 min, and 85 min), as well as GA3 solution soaking (concentration: 0 μmol·L−1, 1443 μmol·L−1). Subsequently, cold stratification (0–5 °C) was applied to investigate the effects of these treatments on seed dormancy release and nutrient transformation. The results indicated that the comprehensive treatment involving magnetic field, GA3 solution soaking, and cold stratification effectively released the physiological dormancy of Tilia seeds and improved germination rates. Among the treatments, M150T85G1443 (magnetic field intensity: 150 MT, magnetic field treatment time: 85 min, GA3 soaking concentration: 1433 μmol·L−1) exhibited the most favorable outcome. After 75 days of cold stratification following the comprehensive treatments, the germination rate of M150T85G1443 seeds reached 89%. Additionally, the levels of storage substances such as starches and crude fats within the seeds decreased, while the utilization of soluble sugars and soluble proteins increased. The M150T85G1443 treatment exhibited the highest degree of variation, leading to gradual increases in metabolic activities of the seeds and a transition from dormancy to germination. [ABSTRACT FROM AUTHOR]

Strains of the ascomycetous yeast Metschnikowia pulcherrima isolated from the internal tissues of fruits were evaluated for phytohormonal activity. IAA production in the culture liquid was determined by the chromatographic method (HPLC-UV). The production of the phytohormones zeatin and gibberellin (GA3) in the culture liquid was determined by a chromatographic method using a quadrupole time-of-flight mass spectrometry detector (Q- TOF LC / MS). IAA and zeatin were detected in the culture liquid of all strains studied. Synthesis of gibberellin (GA3) was detected in only 5 of 18 strains examined. On average, the strains showed the highest activity in the synthesis of IAA (6.668 µg/mL and 2.135 mg/g). Zeatin content was 3 orders of magnitude lower (0.365 ng/mL and 0.129 µg/g) and GA3 content was 4 orders of magnitude lower (0.076 ng/mL and 0.027 µg/g). According to our results, the yeast M. pulcherrima is not an active producer of zeatin and GA3 in amounts relevant to the plant. On the other hand, the average level of IAA synthesis detected in M. pulcherrima strains in this study is within the range of concentrations that can stimulate plant development and growth. Thus, endophytic strains of M. pulcherrima that produce plant-relevant levels of IAA could be improved to increase their synthesis ability and used as plant growth promoters in agricultural crops. [ABSTRACT FROM AUTHOR]

This article discusses a study conducted on three varieties of wheat and the effects of different plant growth promoters on their growth and yield. The results showed that the variety DBW-187 had the highest growth and yield, with significant variations observed among the different plant growth promoters. The application of a mixture of micronutrients as a foliar spray at the tillering stage resulted in the most significant improvements in growth and yield. The study emphasizes the importance of micronutrients and plant growth promoters in enhancing wheat production. [Extracted from the article]

The nutritional value of blue honeysuckle (Lonicera caerulea L.) fruit is abundant; however, its production faces challenges due to a short harvesting period and fruit drop issues. In this study, the effects and potential mechanisms of two different plant growth regulators, GA3 (Gibberellins acid) and 2,4-D (2,4-Dichlorophenoxyacetic acid), on blue honeysuckle fruit abscission and abscission layer formation were investigated. The main cultivated variety of blue honeysuckle, 'Berel', was used as the experimental material. GA3 and 2,4-D were sprayed on the plants from the veraison. The anatomical structure of the fruit abscission zone (FAZ) was observed after treatment. Key enzymes involved in cell wall degradation, pectinase, cellulase, polygalacturonase, and pectin methylesterase, were analyzed for their activities. Furthermore, the gene expression levels of cell wall detachment-related genes CX1, CX2, PL20, PE, and key genes for gibberellin and ethylene synthesis GA2OX1, GA1, ACO, and ACO3 were examined. The results indicated that the application of GA3 and 2,4-D could delay the formation of the abscission layer. In the FAZ treated with GA3 and 2,4-D at 5 DAT, the activity of key enzymes involved in cell wall degradation decreased, the expression of genes related to cell wall degradation enzymes and key genes for ethylene synthesis was inhibited, and the drop of fruit reduced. In conclusion, exogenous application of GA3 and 2,4-D suppresses the abscission of 'Berel' blue honeysuckle fruit, likely through the inhibition of cell wall degradation and abscission layer formation. [ABSTRACT FROM AUTHOR]

Citrus is one of the most important and widely grown fruit crops around the world. Citrus fruit drop is due to the influence of various biotic and abiotic factors. Major biotic factors include insects like fruit flies and diseases such as Huanglongbing (HLB) and postbloom fruit drop (PFD) due to Colletotrichum acutatum. The associated abiotic factors are temperature, rainfall, hailstorms, water stress, nutritional imbalance, etc. Studies have been conducted to understand fruit drop and its relation to various plant growth regulators. Plant growth regulators such as auxin and gibberellins have been categorised as abscission inhibitors, while ethylene, abscisic acid (ABA) and methyl jasmonate (MJ) are abscission promoters. Here, in this review, we have emphasised on the different phases of fruit drops, factors causing fruit drop, the role of plant growth regulators, fruit detachment force (FDF), rootstocks, water relation, nutrient status and different chemical, biological, botanical and hormonal strategies applied for controlling citrus fruit drop. Moreover, we have also discussed the molecular basis of citrus fruit drop and have reviewed recent studies involving biosynthesis/signalling pathway genes and phytohormone genes affecting fruit drop. This review offers comprehensive information about citrus fruit drop and shall provide the direction of future research for students, horticulturists, researchers and other stakeholders. [ABSTRACT FROM AUTHOR]

In newly reclaimed sandy lands, plants face substantial environmental challenges, affecting their productivity, yield, and quality. Gibberellic acid (GA3) is a plant growth regulator physiologically involved in plant responses to abiotic stresses. As agricultural activities expand in desert regions, applications of GA3 could help address adverse plant growth and developmental effects. Here, we investigated the impact of exogenously applied GA3 on the growth of Cape gooseberry (Physalis peruviana L.) in newly reclaimed sandy lands in the arid Nubaria region of the West Delta of Nile, Egypt. Different GA3 concentrations of 100, 150, 200, and 250 ppm were foliar-applied to the plants. The application of GA3 in our study significantly improved the vegetative growth, plant height, leaf and branch count, and the fresh weight and yield of Cape gooseberry plants. Fruit weight, quality soluble solids, and leaf chlorophyll content were also improved. The most pronounced effects were achieved with concentrations of GA3 at 200 and 250 ppm, with the 200-ppm concentration displaying superiority in most parameters. Notably, GA3 treatments enhanced relative water content (RWC), an indicator of water status in arid conditions. Maintaining optimal RWC is crucial for essential processes like photosynthesis, promoting growth, and productivity. This research underscores GA3's potential in enhancing Cape gooseberry growth, yield, and quality, providing a practical strategy for mitigating environmental challenges in arid regions, a concern exacerbated by climate change. [ABSTRACT FROM AUTHOR]

Orostachys spp., considered economically important succulent plants for both the medicinal and ornamental plant industries, are known to exhibit slow growth in their offsets during the long, cold winter months. Due to the slow growth, this study investigated the application of gibberellic acid (GA3) and determined the optimal GA3 concentration (control, 200 mg·L−1, 400 mg·L−1, and 600 mg·L−1) for promoting the propagation of three Orostachys species (i.e., O. fimbriata, O. japonica, and O. minuta), as well as its impact on their growth and development. According to our study findings, O. fimbrata and O. minuta influenced by GA3 exhibited higher survival rates (7–38%) and offset growth rates (3–87%) compared to the control. Similarly, its application resulted in significant shoot and root development, along with increased moisture content for the majority of the species. The results of this research demonstrate the potential and practical applications of using GA3 to increase the propagation and growth of Orostachys spp. during cold conditions for year-round propagation of these succulent plants, which could have ecological and horticultural significance for related species as well as other vegetatively propagated crops. [ABSTRACT FROM AUTHOR]

Chilgoza (Pinus gerardiana) forests naturally exist on the highest elevations of the Himalaya Mountains in the provinces of Paktia, Kunar, Nangarhar, Nuristan, and Paktika in the southeast of Afghanistan. These forests provide a sizable source of income for the people living in these areas. The spread and natural regeneration of chilgoza pine forests is declining in the natural environment as a result of overharvesting, erratic annual seed production, and prolonged dormancy; therefore, it is necessary to find an effective method to enhance seed germination and seedling growth. Application of different Gibberellic Acid (GA3) hormone concentrations (50 ppm, 75 ppm, and 100 ppm), the removal of the seed coat, and control (untreated) treatments were used to conduct an experiment for this study. For each treatment, seedling growth parameters and the percentage of seeds that germinated were examined. The results showed that the T4 treatment had the highest average length of seedling, shoot, and root, measuring 13.34 cm, 8.1 cm, and 8.4 cm, respectively; whereas the T1 treatment had the shortest average lengths of seedling, shoot, and root, measuring 11.22 cm, 6.5 cm, and 6.2 cm, respectively. The greatest percentage of germination (78.66%) was observed in T4 (100 ppm), whereas the lowest percentage (26%) was documented in T1 (Control). The highest average number of leaves was recorded in T4 (22.25) and the lowest in T1 (15.02) treatment. The results indicated that treating chilgoza pine seeds in a 100 ppm solution of GA3 for 24 hours enhances both the seed germination and sprouting seedling growth. [ABSTRACT FROM AUTHOR]

Purpose Juniper (Juniperus procera) is a common forest tree species in Saudi Arabia. The decline in many populations of J. procera in Saudi Arabia is mainly due to seed dormancy and loss of natural regeneration. This study assessed the effects of chemical and hormonal treatments on seed germination and seedling growth in juniper plants. Methods The seeds were subjected to either chemical scarification with 90% sulfuric acid and 20% acetic acid for 6 min or hormonal treatment by seed soaking in two concentrations (50 and 100 ppm) of three growth regulators, namely, indole acetic acid (IAA), gibberellins (GA3), and kinetin, for 72 h. A control group without any seed treatment was also prepared. The experiments were performed in an incubator maintained at room temperature and under a light and dark period of 12 h for 6 w. The germinated seeds for each treatment were counted and removed from the dishes. The selected germinated seeds from different treatments were planted in a greenhouse and irrigated with tap water for another 6 weeks. The hormone-treated seedlings were sprayed with their corresponding hormone concentrations 1 w after planting. Results The highest percentage of seed germination was significantly recorded after seed soaking in 50 ppm GA3, whereas treatment with IAA (100 ppm) resulted in the best seedling growth. Seedlings treated with the three phytohormones showed a significant increase in photosynthetic pigments, total soluble sugars, proteins, percentage of oil, IAA, GA3, and kinetin contents of juniper seedlings compared with the control value, whereas abscisic acid content was decreased compared with chemical treatments. Conclusion The investigated different treatments had an effective role in breaking seed dormancy and improving seedling growth of J. procera, which is facing a notable decline in its population worldwide. Moreover, such an effect was more pronounced in the three phytohormones that succeeded in breaking dormancy and growth of the Juniperus plant than in the other treatments.