Application Of GA3 Research Articles

Synergistic effects of gibberellic acid, biochar, and rhizobacteria on wheat growth under heavy metal and drought stress

Wheat (Triticum aestivum L.), a vital crop constituting approximately 20% of global caloric intake, faces significant threats from heavy metal contamination, particularly cadmium (Cd) and chromium (Cr), along with drought stress, jeopardizing global food security. This study aimed to investigate the combined effects of these stressors and the potential of plant growth enhancers such as gibberellic acid (GA3), biochar (BC), and rhizobacteria to improve wheat growth. Conducted in a controlled greenhouse environment at The Islamia University of Bahawalpur, the experiment utilized a completely randomized design with three replications across 72 pots, each filled with clay loam soil. The experimental layout included 24 treatment combinations involving cadmium stress (6 mg/kg), chromium stress (300 and 600 mg/kg), drought stress simulated at -0.8 MPa soil water potential, and various applications of GA3 (200 mg L− 1) and biochar (0.6% and 0.9% w/w). Seedlings of T. aestivum cv. Dilkash-21, treated with Agrobacterium fabrum, showed significant growth metrics, with root lengths of 9.36 cm under 6 mg/kg Cd stress compared to 5.53 cm in controls. The treatment also increased shoot and root fresh weights by 24.7% and 22.5%, respectively, while chlorophyll content peaked at 2.26 mg/g under 6 mg/kg Cd. Additionally, electrolyte leakage decreased to 10.5%, and the vigor index improved to 1586.05 under Cd stress. These findings indicate that utilizing GA3 and biochar can mitigate the adverse effects of environmental stressors on wheat. Future research should focus on the underlying mechanisms of these treatments and explore their application in field conditions to further enhance wheat productivity and resilience against environmental stress.

The SLR1-OsMADS23-D14 module mediates the crosstalk between strigolactone and gibberellin signaling to control rice tillering.

Strigolactones (SLs) and gibberellins (GAs) have been found to inhibit plant branching or tillering, but molecular mechanisms underlying the interplay between SL and GA signaling to modulate tillering remain elusive. We found that the transcription factor OsMADS23 plays a crucial role in the crosslink between SL and GA signaling in rice tillering. Loss-of-function mutant osmads23 shows normal axillary bud formation but defective bud outgrowth, thus reducing the tiller number in rice, whereas overexpression of OsMADS23 significantly increases tillering by promoting tiller bud outgrowth. OsMADS23 physically interacts with DELLA protein SLENDER RICE1 (SLR1), and the interaction reciprocally stabilizes each other. Genetic evidence showed that SLR1 is required for OsMADS23 to control rice tillering. OsMADS23 acts as an upstream transcriptional repressor to inhibit the expression of SL receptor gene DWARF14 (D14), and addition of SLR1 further enhances OsMADS23-mediated transcriptional repression of D14, indicating that D14 is the downstream target gene of OsMADS23-SLR1 complex. Moreover, application of exogenous SL and GA reduces the protein stability of OsMADS23-SLR1 complex and promotes D14 expression. Our results revealed that SLs and GAs synergistically inhibit rice tillering by destabilizing OsMADS23-SLR1 complex, which provides important insights into the molecular networks of SL-GA synergistic interaction during rice tillering.

Effect of branch girdling on the alternate bearing, yield, and fruit quality of grapefruit (Citrus paradisi Macf.)

Objective: The objective of this research was to evaluate the effect of girdling branches, application of gibberellic acid (GA3), and foliar urea on the alternating yield and quality of grapefruit (Citrus paradisi Macf) fruits. Design/methodology/approach: The experiment was carried out on trees during abundant harvest (“on” year) and trees with low harvest (“off” year). Foliar applications of GA3 and foliar urea were performed with a manual sprayer at a rate of 7 L tree-1 of solution. Branch girdling (5.0 mm wide) was performed on two-thirds of the secondary branches using a circular-edged knife to avoid damaging the xylem. The experimental design was completely randomized, with 24 factorial arrangements with 16 treatments and 3 repetitions. Each experimental unit was a tree to evaluate fruit yield and quality at the experiment's conclusion. Results: Branch girdling increased the diameter, the number of fruits, the yield, and the ºBrix-Acidity ratio of the juice. Foliar urea applications increased the percentage of juice but delayed ripening. The combination of branch girdling plus foliar urea applications increased fruit weight. The yield increase was attributed to the number of fruits rather than their weight. The treatments did not reduce alternate bearing. Limitations on study/implications: The commercial cultivation areas for the experiment were limited due to the availability of facilities for testing fruit quality. Findings/conclusions: To increase the size and number of fruits, with an increase in yield, branch girdling is an effective option. Furthermore, the application of foliar urea increases the percentage of juice and fruit weight, with a slight delay in maduration. However, the treatments did not reduce alternate bearing. Future research is required with other grapefruit varieties at different application times.

Computational Investigation of Pristine, Al-, and Ga-Doped Zn12O12 nanoclusters as Detection Platforms for Methadone in gas and solvent phases

Electrochemical sensors are emerging as promising tools for point-of-care diagnostic medical devices, benefiting from advancements in nanomaterials. These nanomaterials enable the development of smaller, more sensitive, and selective sensors while reducing fabrication and maintenance costs. This work presents a comprehensive theoretical investigation of the potential application of pristine, Ga- and Al-doped Zn12O12 nanoclusters for detecting methadone, a critical analyte in various medical and law enforcement applications. Employing density functional theory (DFT) calculations at the B3LYP-D level with the 6-311G (d, p) basis set, we have elucidated the interactions between these nanoclusters and methadone. The results reveal that methadone exhibits intense adsorption energies of -41.02, -39.79, and -59.77 kcal/mol on the pristine Zn12O12, GaZn11O12, and AlZn11O12 nanoclusters, respectively, in their most stable configurations. The doped nanoclusters, GaZn11O12 and AlZn11O12, displayed significant gap energies (Eg) changes upon methadone adsorption, indicating enhanced sensitivity towards this analyte. The UV-Vis spectroscopic analysis showed that methadone adsorption on the GaZn11O12 and AlZn11O12 nanoclusters led to distinct spectral shifts and oscillator strength variations compared to the Zn12O12 nanocluster. The transition theory calculations highlighted the GaZn11O12 nanocluster's short recovery time of 0.44 seconds, a crucial attribute for practical applications. Solvent effect studies demonstrated the stability of the methadone/GaZn11O12 complex in water and revealed its heightened polarization, as evidenced by the increased dipole moment. These findings suggest that the GaZn11O12 nanocluster is a promising candidate for detecting methadone in gas and liquid phases, with favorable attributes such as high sensitivity, rapid reversibility, and stability in gas and aqueous environments. Thus, this nanocluster can be used in sensor devices.

Synergistic Effects of Seed Inoculation with Piriformospora indica and Foliar Hormonal Application on Early Flowering in Rice Bean (Vigna umbellata) Variety Surabhi

This study aimed to evaluate the effectiveness of seed inoculation with Piriformospora indica and various foliar hormonal treatments in promoting early flowering in fodder rice bean (Vigna umbellata Thunb.), variety Surabhi, conducted at the College of Agriculture, Vellayani. The experiment was laid out in randomized block design with ten treatments and three replications. The plot size of 3 m2 was followed in the field experiment. The experiment assessed the impact of different treatments on flowering and other biometric traits in the leguminous crop. The treatments included untreated control, seed inoculation with Piriformospora indica before sowing and foliar applications of salicylic acid (100 ppm,150 ppm), GA₃ (200 ppm,300 ppm), Paclobutrazol (10 ppm,20 ppm) and KNO₃ (1%,1.5%) at 30 days after sowing (DAS). The results revealed that significant differences were observed among treatments for all thirteen biometric traits measured. Early flowering was recorded in plants treated with salicylic acid @ 100 ppm(65.35 days), followed by GA₃ @ 300 ppm (67.72 days), salicylic acid @ 150 ppm (67.81 days), and Paclobutrazol @ 10 ppm (69.87 days), whereas the control flowered last (80.96 days. The findings suggest that the application of specific concentrations of growth regulators and seed inoculation with P.indica can effectively reduce the time to flowering, enhancing the potential for improved seed production in fodder rice bean.

Combined transcriptomic, metabolomic and physiological analysis reveals the key role of nitrogen, but not phosphate and potassium in regulating anthocyanin biosynthesis induced by nutrient deficiency in Eucalyptus

Anthocyanin biosynthesis in Eucalyptus plants can be flexibly and rapidly modulated in response to hormones or environmental stimuli, including nutrient deprivation (ND). However, the underlying mechanism of ND in inducing anthocyanin biosynthesis in plants remains largely elusive. In this study, we discovered that anthocyanin levels in leaves and stems could well reflect nitrogen availability in Eucalyptus. Supplementation with nitrogen, but not with phosphate or potassium, effectively inhibited ND-induced anthocyanin biosynthesis. To further investigate how nitrogen regulates this process, comprehensive time-resolved transcriptomic and targeted metabolomic analyses were conducted. The results revealed that 3405, 2706, and 3153 genes were differentially regulated by nitrogen treatment at 1, 2, and 3 d, respectively. Pathway analysis indicated the majority of the enriched KEGG pathways were associated with cellular metabolism, such as amino acid and flavonoid biosynthesis. Moreover, metabolomic analysis showed that the most abundantly accumulated anthocyanins, cyanidin-3-O-galactoside and cyanidin-3-O-glucoside, along with key intermediates in the flavonoid pathway, were downregulated by nitrogen treatment. Furthermore, nitrogen-responsive MYB-bHLH-WDR complex genes were identified, including six EgrMYB113 family members. Overexpression of one of the EgrMYB113-like genes induced anthocyanin biosynthesis in the transgenic hairy roots of Eucalyptus. Interestingly, mutation of AtMYB113 inhibited nitrogen deficiency-induced anthocyanin biosynthesis in Arabidopsis, suggesting that MYB113 is a novel N-responsive MYB transcriptional regulator of anthocyanin biosynthesis. Additionally, nitrogen treatment upregulated a few GA biosynthesis genes while simultaneously downregulated the expression of several GA2ox genes. Exogenous application of GA3 decreased ND-induced anthocyanin biosynthesis. Conclusively, this study provides novel insights into the molecular mechanism of nitrogen in the regulation of anthocyanin biosynthesis in Eucalyptus.

USE OF PLANT GROWTH REGULATORS TO OBTAIN MINI TUBERS OF Dioscorea remotiflora Kunth IN MICROPROPAGATED PLANTS

<p><strong>Background:</strong> Camote de cerro (<em>Dioscorea remotiflora</em> Kunth) stands out as a crop option in protected agriculture in Mexico due to its agronomic benefits and its versatility in the food and pharmaceutical industries. Despite its potential, it is not commercially cultivated in the country motivating the need to develop an efficient propagation method from vegetative planting material. Previous research suggests that the use of growth retardants stimulates root growth and carbohydrates accumulation in tubers, while applying gibberellic acid (GA<sub>3</sub>) is strongly related with greater tuber production. <strong>Objective: </strong>To evaluate the effect of different growth regulators to obtain <em>D. remotiflora</em> mini tubers.<strong> Methodology: </strong>Two experiments to obtain mini tubers were carried out. The first one evaluated mediums of culture <em>in vitro</em>: MS and MS + 0.5 mg L<sup>-1</sup> paclobutrazol (PBZ). In the second, effects of foliar application of GA<sub>3</sub>, PBZ and trinexapac ethyl (TNE) were evaluated. Both experiments were carried out in two accesions of <em>D. remotiflora</em> plants propagated <em>in vitro</em> and adapted to greenhouse conditions. <strong>Results:</strong> An increase in mini tubers yield and in their weight was observed when seedlings were propagated in MS + 0.5 mg L<sup>-1</sup> PBZ and GA<sub>3</sub> was applied to foliage. <strong>Implications:</strong> The use of growth retardants showed efficiency in developing mini tubers; nevertheless, more research focusing on concentrations and combinations of these substances is needed to improve the protocol to obtain planting material. <strong>Conclusions:</strong> The observed effect of growth retardants and gibberellic acid application in <em>Dioscorea remotiflora</em> plants suggests a favorable influence in the development of mini tubers. In the long term, this phenomenon could contribute significantly to promoting viability of its commercial cultivation and rehabilitation of previously exploited areas.</p>

Three RLKs integrate SHR-SCR and gibberellins to regulate root ground tissue patterning in Arabidopsis thaliana

Precise regulation of cell division is essential for proper tissue patterning in multicellular organisms. In Arabidopsis, the ground tissue (GT) comprises cortex and endodermis in the early stages of root development. During GT maturation, additional periclinal cell divisions (PCDs) occasionally occur of the endodermis, generating a middle cortex (MC) layer between the cortex and endodermis. Although several regulatory proteins and phytohormones were identified to mediate GT patterning, such as SHORT-ROOT (SHR), SCARECROW (SCR), CYCLIND6;1 (CYCD6;1), and gibberellins (GAs), the interrelationship among these factors is not elucidated. Here, we report that three closely related receptor-like kinases (RLKs), ARH1, FEI1, and FEI2, play crucial roles in mediating a signal transduction pathway from the SHR-SCR module to GA to regulate GT patterning. Two independent triple mutants of these RLKs (tri-1 and tri-2) exhibit increased MC formation compared with wild type. Genetic analysis indicated that all three RLKs regulate MC formation mainly in a cell-autonomous manner. The transcription levels of these RLKs are negatively controlled by SHR and SCR. The altered GT patterns in shr and scr can be partially complemented by tri-1. GA biosynthesis is significantly reduced in the roots of tri-1. The excessive MC formation in tri-1 can be greatly suppressed by the exogenous application of GA3 or by the mutation of CYCD6;1. Our results demonstrate a signaling pathway involving SHR/SCR-ARH1/FEI1/FEI2-GA-CYCD6;1 to govern GT patterning in Arabidopsis thaliana.

Unveiling the potential role of gibberellic acid, melatonin and indole acetic acid on parthenocarpy, physiological traits and phytochemical responses in Hibiscus sabdariffa L

The economic part of the Hibiscus sabdariffa L. (Malvaceae) plant is the sepal. One of the main challenges in harvesting this product is separating its seeds, which are surrounded by sepals. If the parthenocarpy process occurs without seeds, the labor costs are reduced and the profits from the production of this plant are increased. In current study, the effect of gibberellic acid (GA3), melatonin (M), and indole acetic acid (IAA) on the induction of parthenocarpy in H. sabdariffa plants was investigated. The study was conducted as a factorial experiment in the form of randomized complete block design with three replications. Different concentrations of GA3 (0 (control), 700, 800, and 900 ppm), M (0 (control), 100, 200, and 400 ppm), and IAA (0 (control), 1000, 1200, and 1400 ppm) were foliar sprayed after the emergence of the flower bud on the 50th, 60th, and 70th days of planting, and the control plants were also sprayed with distilled water. Various measurements were taken including the number of seeds per boll, parthenocarpy percentage, capsule volume, number of bolls per plant, number of mature seeds, and phytochemical parameters such as anthocyanin, chlorophyll and carotenoid content, antioxidant value, total phenol and flavonoid content, and soluble solids. The application of GA3 at 800 and 900 ppm along with IAA at 1000 ppm and M at 100 and 200 ppm led to the production of parthenocarpy fruits and showed the best results in the induction of parthenocarpy. The control group indicated the highest number of mature seeds per boll. The highest amount of phenol and flavonoid contents were obtained in plants treated with GA3 at 800 ppm. For anthocyanin, the control group showed the highest value (1.63 mg g−1), and in the case of the antioxidant trait, plants exposed to 100 ppm M showed the highest IC50 (40.68%). Hence, the application of plant growth regulators with appropriate concentrations can be effective in inducing parthenocarpy in H. sabdariffa plants. Additionally, parthenocarpy-induced by GA3, IAA, and M had different impacts on fruit quality and quantity, suggesting that the effect depends on the type of employed hormones used and their concentrations.

Determination of the Effects of Aminoethoxyvinilglycine (AVG) and Gibberellic Acid (GA3) Applications on Pre-Harvest Fruit Drop Amount and Fruit Quality in Hakko Pear Cultivar

This study was conducted to determine the effects of pre-harvest Aminoethoxyvinylgylcine (AVG) and Gibberellic acid (GA3) applications on the pre-harvest fruit drop amount and fruit quality in the 'Hakko' pear (Pyrus pyrifolia) cultivar grafted on BA29 rootstock in a private orchard in the Bala district of Ankara in 2021-2022. It was conducted in an orchard belonging to a producer. 50-100-150 mg/l AVG and 25-50-75 mg/l GA3 were applied 4 weeks before the estimated harvest date. Fruits are harvested at full maturity date; Pomological properties such as cumulative drop percentage, yield, fruit weight, fruit width and length, fruit stem width and length, fruit flesh firmness, fruit color, and chemical properties such as soluble solids content (SSC), pH and titratable acidity (TA) were evaluated. It was observed that all doses of AVG and GA3 during the harvest period reduced the cumulative casting rate compared to the control application (6.78%). In general, the yield per tree was found to be high in GA3 applications. In both AVG and GA3 applications, its effects on fruit weight, fruit width and length, fruit flesh firmness, SSC and pH were found to be statistically significant. It was observed that in both AVG and GA3 applications, the amount of fruit drop pre-harvest decreased and fruit quality characteristics were better than the control.

Genotypic variations in postfertility traits and yield components of mung bean (Vigna radiata (L.) R. Wilczek) germplasms in Chitwan, Nepal

Assessment of economic traits of germplasms, which are associated with genetic variation, is vital for mung improvement. Therefore, by wielding the randomized complete block design with 3 replications, a probe analysis using multiple trait stability indexing and analysis of variance with Duncan's test at p ≤ 0.05 is performed to compare the means of yield attributes. Moreover, simultaneous application of GA3 and NAA (50 mg/L each) was carried out at 30 DAS and at mid-flowering. Pondering not only factorial analysis but also correlation and path studies revealed that flower shedding before and 12 h after spraying is nearly detrimental to yield. In addition, yield/plant was positively (p < 0.001, r = 0.67–0.96) correlated with the harvesting index and test weight. 'Pratigya', demonstrating heightened sensitivity to environmental cues—unveils increased sensitivity—while 'VC3960A-88′ flourished with hormone-boosted pod formation. 'VC6368(46-40-3)' packed 11 pods/cluster, and 'CN95' thrived, excelling in abundant grains as well as clusters. Notably, 'VC6370-A′ topped yielder, whereas CN95 augmented an efficient harvest index of 0.48. Moreover, path analysis revealed that all postfertility traits are inherently associated with yield. By employing 17 % selection intensity, the MTSI unequivocally ascertained that not only 'VC6370A' but also 'CN95' are the ideal stable and prime performing genotypes for yield(3.04–2.8 tons/ha) as well as interactive traits, a marker for simultaneous selection, as well as improvement. The MTSI view of strengths and weaknesses harbingers that breeders need to focus on increasing the number of genotypes with the desired phenotypes—lower flower abscission, greater grain dimensions and pod setting, harvesting indices, and yields/ha.

Foliar application of IAA and GA3 on growth and yield attributes of mungbean (Vigna radiata L. R. Wilczek)

A field experiment was conducted to assess the effects of foliar application of Indole acetic acid (IAA) and Gibberellic acid (GA3) on the growth and yield of mungbean (BARI Mung-6) plants. Nine treatments were administered, including various concentrations of IAA and GA3, applied individually and in combination. The experiment followed a randomized complete block design (RCBD) with three replications, data were recorded on growth and yield parameters at 30 days after sowing (DAS) and at harvest. Results indicated that treatment T8 (IAA 50 mg/l + GA3 50 mg/l) significantly enhanced growth and yield attributes. Notably, T8 exhibited the highest values for plant height (57.50 cm), number of leaves per plant (47.33), number of branches per plant (7.67), chlorophyll content (55, SPAD value), shortest duration to 80% flowering (27.33) with 80% pod maturity (55.33), number of pods per plant (37.67), pod length (14.99 cm), number of seeds per pod (13.78), weight of 1000 seeds (54.95 g), seed yield (1.68 t/ha), biological yield (3.52 t/ha), and harvest index (47.73%). Conversely, the untreated control (T0) exhibited the lowest performance across all parameters. Therefore, foliar application of IAA and GA3, particularly at 50 mg/l concentration each, demonstrated significant improvements in growth, yield, and related attributes of mungbean. Bangladesh J. Bot. 53(3): 459-464, 2024 (September)

Gibberellins Play an Essential Role in the Bud Growth of Petunia hybrida.

This study delves into the role of gibberellin (GA) in governing plant branch development, a process that remains incompletely understood. Through a combination of exogenous hormone treatment, gene expression analysis, and transgenic phenotype investigations, the impact of GA on petunia's branch development was explored. The results showed that GA3 alone did not directly induce axillary bud germination. However, paclobutrazol (PAC), an inhibitor of GA synthesis, effectively inhibited bud growth. Interestingly, the simultaneous application of GA3 and 6-BA significantly promoted bud growth in both intact and decapitated plants compared to using 6-BA alone. Moreover, this study observed a significant downregulation of GA synthesis genes, including GA20ox1, GA20ox2, GA20ox3, GA3ox1, and CPS1, alongside an upregulation of GA degradation genes such as GA2ox2, GA2ox4, and GA2ox8. The expression of GA signal transduction gene GID1 and GA response factor RGA was found to be upregulated. Notably, the PhGID1 gene, spanning 1029 bp and encoding 342 amino acids, exhibited higher expression in buds and the lowest expression in leaves. The overexpression of PhGID1 in Arabidopsis resulted in a noteworthy rise in the number of branches. This study highlights the crucial role of GA in bud germination and growth and the positive regulatory function of GA signaling in shoot branching processes.

Inflorescence development in female cannabis plants is mediated by photoperiod and gibberellin.

In cannabis seedlings, the initiation of solitary flowers is photoperiod-independent. However, when cannabis reaches the adult stage, short-day photoperiod (SD) triggers branching of the shoot apex and a reduction in internode length, leading to development of a condensed inflorescence. We demonstrate that SD affects cannabis plants in two distinct phases: the first includes rapid elongation of the internodes and main stem, and occurring from Day 5 to Day 10 of plant cultivation under SD; in the second phase, elongation of newly developed internodes ceases, and a condensed inflorescence is formed. Exposure of plants to alternating photoperiods revealed that inflorescence onset requires at least three consecutive days of SD, and SD is consistently required throughout inflorescence maturation to support its typical condensed architecture. This photoperiod-dependent morphogenesis was associated with a decrease in gibberellin (GA4) and auxin levels in the shoot apex. Reverting the plants to a long-day photoperiod (LD) increased GA4 and auxin levels, leading to inflorescence disassembly, internode elongation, and subsequent resumption of LD growth patterns. Similar developmental patterns were observed under SD following the application of exogenous GA (and not auxin), which also impeded inflorescence development. Nevertheless, additional studies will help to further evaluate auxin's role in these developmental changes. We propose a crucial role for GA in sexual reproduction and inflorescence development in female cannabis by mediating photoperiod signaling in the inflorescence tissues.

The crosstalk interaction of ethylene, gibberellins, and arbuscular mycorrhiza improves growth in salinized tomato plants by modulating the hormonal balance

Ethylene (ET) and gibberellins (GAs) play key roles in controlling the biotic and abiotic interactions between plants and environment. To gain insights about the role of ET and GAs interactions in the mycorrization and response to salinity of tomato (Solanum lycopersicum L.) plants, the ET-insensitive (Never-ripe, Nr), and the ET-overproducer (Epinastic, Epi) mutants and their wild type cv. Micro-Tom (MT), were inoculated or not with the arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis and exposed to control (0 mM NaCl) and salinity (100 mM NaCl) conditions, with and without gibberellic acid (10−6 M GA3) application during four weeks. Exogenous GA3 enhanced plant growth irrespective of the genotype, AMF, and salinity conditions, while an additional effect on growth by AMF was only found in the ET-overproducer (Epi) mutant under control and salinity conditions. Epi almost doubled the AMF colonization level under both conditions but was the most affected by salinity and GA3 application compared to MT and Nr. In contrast, Nr registered the lowest AMF colonization level, but GA3 produced a positive effect, particularly under salinity, with the highest leaf growth recovery. Foliar GA3 application increased the endogenous concentration of GA1, GA3, and total GAs, more intensively in AMF-Epi plants, where induced levels of the ET-precursor ACC were also found. Interestingly, GA4 which is associated with AMF colonization, registered the strongest genotype x GA x AMF × salinity interactions. The different growth responses in relation to those interactions are discussed.

Role of auxin and gibberellin under low light in enhancing saffron corm starch degradation during sprouting

The mechanisms by which low light accelerates starch macromolecules degradation by auxin and gibberellin (GA) in geophytes during sprouting remain largely unknown. This study investigated these mechanisms in saffron, grown under low light (50 μmol m−2 s−1) and optimal light (200 μmol m−2 s−1) during the sprouting phase. Low light reduced starch concentration in corms by 34.0 % and increased significantly sucrose levels in corms, leaves, and leaf sheaths by 19.2 %, 9.8 %, and 134.5 %, respectively. This was associated with a 33.3 % increase in GA3 level and enhanced auxin signaling. Leaves synthesized IAA under low light, which was transported to the corms to promote GA synthesis, facilitating starch degradation through a 228.7 % increase in amylase activity. Exogenous applications of GA and IAA, as well as the use of their synthesis or transport inhibitors, confirmed the synergistic role of these phytohormones in starch metabolism. The unigenes associated with GA biosynthesis and auxin signaling were upregulated under low light, highlighting the IAA-GA module role in starch degradation. Moreover, increased respiration rate and invertase activity, crucial for ATP biosynthesis and the tricarboxylic acid cycle, were consistent with the upregulation of related unigenes, suggesting that auxin signaling accelerates starch degradation by promoting energy metabolism. Upregulated of auxin signaling (CsSAUR32) and starch metabolism (CsSnRK1) genes under low light suggests that auxin directly regulate starch degradation in saffron corms. This study elucidates that low light modulates auxin and GA interactions to accelerate starch degradation in saffron corms during sprouting, offering insights for optimizing agricultural practices under suboptimal light conditions.

The effect of exogenous gibberellin and its synthesis inhibitor treatments for morphological and physiological characteristics of Tartary buckwheat

Gibberellin (GA3) is an important plant hormone involved in many physiological and developmental processes in plants. However, the physiological mechanism of GA3 on the regulation yield and grain shell thickness of Tartary buckwheat is still unclear. In this study, the thick-shelled cultivar “Jinqiao 2” and thin-shelled cultivar “Miku 18” were used to study the effects of different concentrations (0, 50, and 100 mg L−1) of exogenous GA3 and chlorocholine chloride (CCC, GA3 synthesis inhibitor) on the cellulose content, amylase, and sucrose synthase (SS) activity in grain shell and the yield of Tartary buckwheat. The application of exogenous GA3 can improve the cellulose content and the activity of amylase and SS in the grain shell of the two Tartary buckwheat varieties. It can also increase the main stem node number, main stem branch number, grains per plant, and yield. Compared with the control treatment (CK, 0 mg L−1), the 100 mg/L exogenous GA3 treatment increased the number of grains per plant, grain weight per plant, 1000-grain weight, and yield of Jinqiao 2 by 20.1%, 41.9%, 13%, and 34.7%, respectively. These items of Miku 18 were increased by 26%, 15.2%, 10.2%, and 23.8%. The application of CCC reduced the activity of amylase and SS and cellulose content in grain shell. In addition, it decreased the main stem node number, main stem branch number, grains per plant, and yield of Tartary buckwheat. In summary, exogenous GA3 treatment not only improved the yield of Tartary buckwheat but also increased the thickness of grain shell by enhancing the activity of amylase and SS and promoting the synthesis and accumulation of cellulose. The results can provide theoretical references for clarifying the physiological mechanism of the difference in shell thickness between Tartary buckwheat varieties.

Effect of Exogenous Application of Humic Acid, GA3 and Vermiwash on Growth, Yield and Quality of Cabbage (Brassica oleracea var. capitata L.) under Valley Condition of Srinagar Garhwal

The effect of exogenous application of humic acid, GA3 and vermiwash on the growth, yield and quality of cabbage was studied in a field experiment. The experiment was conducted in a randomized block design at the Horticultural Research Centre, Chauras Campus, H.N.B. Garhwal University, Srinagar, Uttarakhand, with three replications and ten treatments. All of the growth, yield and quality contributing characteristics of cabbage were found to be significant. The growth parameters at 30, 45 DAT and at harvest were found to be maximum under T9 (GA3 @ 150 ppm). Yield parameters were found to be highest in T9 (GA3 @ 150 ppm) total plant weight (2188.67 g), average weight of head (1454.33 g), yield per hectare (321.43 q) whereas dry weight of head (10.00 g) in T6 (Vermiwash @ 100%), head diameter (18.98 cm) and core diameter (4.53 cm) in T8 (GA3 @ 100 ppm) and core length (8.62 cm) in T1 (Humic acid @ 100 ppm). Quality parameters were found to be highest under T6 (Vermiwash @ 100%) for head compactness (35.39%), whereas total soluble solids (5.20 0Brix) in T3 (Humic acid @ 200 ppm) and ascorbic acid (56.07 mg) in T1 (Humic acid @ 100 ppm). Economic parameters were found to be highest under T6 (Vermiwash @ 100%) for cost of cultivation (1,92,510 ₹/ha), gross return (10,66,030 ₹/ha) and net return (8,73,520 ₹/ha). Hence, it may be suggested that concentration of 150 ppm GA3 could use for enhancing the production of cabbage under subtropical condition of Srinagar Garhwal

The SINA1-BSD1 Module Regulates Vegetative Growth Involving Gibberellin Biosynthesis in Tomato.

In plants, vegetative growth is controlled by synergistic and/or antagonistic effects of many regulatory factors. Here, the authors demonstrate that the ubiquitin ligase seven in absentia1 (SINA1) mammalian BTF2-like transcription factors, Drosophila synapse-associated proteins, and yeast DOS2-like proteins (BSD1) function as a regulatory module to control vegetative growth in tomato via regulation of the production of plant growth hormone gibberellin (GA). SINA1 negatively regulates the protein level of BSD1 through ubiquitin-proteasome-mediated degradation, and the transgenic tomato over-expressing SINA1 (SINA1-OX) resembles the dwarfism phenotype of the BSD1-knockout (BSD1-KO) tomato plant. BSD1 directly activates expression of the BSD1-regulated gene 1 (BRG1) via binding to a novel core BBS (standing for BSD1 binding site) binding motif in the BRG1 promoter. Knockout of BRG1 (BRG1-KO) in tomato also results in a dwarfism phenotype, suggesting BRG1 plays a positive role in vegetative growth as BSD1 does. Significantly, GA contents are attenuated in transgenic SINA1-OX, BSD1-KO, and BRG1-KO plants exhibiting dwarfism phenotype and exogenous application of bioactive GA3 restores their vegetative growth. Moreover, BRG1 is required for the expression of multiple GA biosynthesis genes and BSD1 activates three GA biosynthesis genes promoting GA production. Thus, this study suggests that the SINA1-BSD1 module controls vegetative growth via direct and indirect regulation of GA biosynthesis in tomato.

Quantitative Proteomics Analysis of ABA- and GA3-Treated Malbec Berries Reveals Insights into H2O2 Scavenging and Anthocyanin Dynamics.

Abscisic acid (ABA) and gibberellic acid (GA3) are regulators of fruit color and sugar levels, and the application of these hormones is a common practice in commercial vineyards dedicated to the production of table grapes. However, the effects of exogenous ABA and GA3 on wine cultivars remain unclear. We investigated the impact of ABA and GA3 application on Malbec grapevine berries across three developmental stages. We found similar patterns of berry total anthocyanin accumulation induced by both treatments, closely associated with berry H2O2 levels. Quantitative proteomics from berry skins revealed that ABA and GA3 positively modulated antioxidant defense proteins, mitigating H2O2. Consequently, proteins involved in phenylpropanoid biosynthesis were downregulated, leading to decreased anthocyanin content at the almost ripe stage, particularly petunidin-3-G and peonidin-3-G. Additionally, we noted increased levels of the non-anthocyanins E-viniferin and quercetin in the treated berries, which may enhance H2O2 scavenging at the almost ripe stage. Using a linear mixed-effects model, we found statistical significance for fixed effects including the berry H2O2 and sugar contents, demonstrating their roles in anthocyanin accumulation. In conclusion, our findings suggest a common molecular mechanism by which ABA and GA3 influence berry H2O2 content, ultimately impacting anthocyanin dynamics during ripening.