Gibberellic Acid Research Articles

Analysis of Trait Variation and Correlations in Hybrid Rice Seed Production Using CMS Breeding Techniques

Imperfect panicle emergence in Cytoplasmic Male Sterile (CMS) lines is a hindrance for hybrid rice seed (F1) production. In CMS lines 10-15% of spikelets remaining enclosed within the flag leaf. This limits their availability for outcrossing, thereby reducing the efficiency of hybrid rice seed production. To mitigate this issue, the application of gibberellic acid (GA3) is a common practice. However, the high cost of GA3 poses a significant barrier for middle-class farmers involved in hybrid rice seed production. This study aims to identify low-cost chemical alternatives to GA3. We evaluated ten different treatments, including a control, on CMS (A) line rice plants. Our findings indicate that penicillin is the most effective treatment, offering high yield at a reduced cost. According to the yield component, treatment-2 (penicillin) reflected grain yield 71.26 g plant -1 which is highest among all the treatments. Potassium dichromate also performed well in promoting panicle emergence. Characters showing positive and significant correlations among different traits are expected to improve yield and can be selected for further advancement in hybrid rice seed production.

MEDIATOR15 destabilizes DELLA protein to promote gibberellin-mediated plant development.

Mediator, a transcriptional coactivator, regulates plant growth and development by interacting with various transcriptional regulators. MEDIATOR15 (MED15) is a subunit in the Mediator complex potentially involved in developmental control. To uncover molecular functions of Arabidopsis MED15 in development, we searched for its interactors. MED15 was found to interact with DELLA proteins, which negatively regulate gibberellic acid (GA) signaling and positively regulate GA biosynthesis. Mutants and overexpressors of MED15 exhibited multiple GA-related growth phenotypes, which resembled the phenotypes of the DELLA overexpressor and mutant, respectively. Consistent with this observation, DELLA protein levels were inversely correlated with MED15 protein levels, suggesting that MED15 activates GA signaling through DELLA degradation. MED15 was required not only for DELLA-mediated induction of GA-biosynthesis gene expression but also for GA-mediated degradation of DELLA. Therefore, MED15 facilitates DELLA destruction not only by promoting GA biosynthesis but also by accelerating DELLA turnover. Furthermore, MED15-mediated GA signaling was required for timely developmental responses to dark and warm conditions. Our results provide insight into developmental control by Mediator via precise regulation of DELLA stability. These findings are potentially useful for the generation of new crop cultivars with ideal body architecture.

Influence of some plant growth regulators on fruit set, yield and quality of sugar apple (Annona squamosa L.) var. Arka Neelachal Vikram

Aim: To evaluate the efficacy of foliar application of homobrassinolide (HBL), gibberellic acid (GA3), and naphthalene acetic acid (NAA) for improving fruit set, yield, and quality in sugar apple. Methodology: The experiment was laid out in a randomized block design with 10 treatments, comprised of NAA (50, 100, and 150 ppm), HBL (0.1, 0.3, and 0.5 ppm), GA3 (100, 150, and 200 ppm), and water as a control. Treatments were foliar sprayed thrice during major flowering period at monthly interval, i.e., April, May, and June. Observations were recorded on fruiting, yield, and fruit quality parameters. Results: Foliar application of GA3 at 150-200 ppm was found effective for enhancing the fruit set, fruit retention, and yield in sugar apple, when applied during May and June. Application of GA3 @ 200 ppm not only recorded the maximum fruit set and retention in May (5.03 and 69.18 %) and June flowering (9.38 and 75.35 %), but also scored the maximum values for number of fruits, fruit weight, and yield in their corresponding month of harvesting, i.e., October (50.60 fruits per tree, 235.70 g per fruit, and 11.88 kg per tree) and November (36.79 fruits per tree, 231.88 g per fruit, and 8.40 kg per tree). With respect to fruit quality, GA3 (100-200 ppm) and NAA (100-150 ppm) registered a significant improvement in various fruit quality parameters, however, GA3 treatments excelled in the performance. Fruits harvested from 200 ppm GA3 had the best quality (pulp: 72.07 %, TSS: 23.90 ºB, TSS/acid ratio: 59.81, total sugar: 30.37 %, reducing sugar: 19.57 %, non-reducing sugar: 10.80 %, vitamin C: 52.34 mg 100 g−1 pulp, total flavonoid: 44.21 mg QE 100 g−1 FW, ferric reducing antioxidant power: 40.73 mM Fe(II) 100 g−1 FW and scavenging activity: 74.65 %), followed by 150 ppm GA3. Interpretation: In sugar apple, foliar application of GA3 (150-200 ppm) twice during May and June flowering is effective for improving fruit set and enhancing yield and quality of the produce. Key words: Fruit set, Fruit quality, Gibberellic acid, Plant growth regulators, Sugar apple

Optimization of Gibberellic Acid Production from Fusarium incarnatum and Its Effect on Zea mays Growth Promotion and Antioxidant Activity

Optimization of Gibberellic Acid Production from Fusarium incarnatum and Its Effect on Zea mays Growth Promotion and Antioxidant Activity

Computational analysis of Allium sativum compounds to identify thermolabile hemolysin inhibitors against Vibrio alginolyticus in shrimp

Vibrio alginolyticus is one of the major disease-causing bacteria in shrimp aquaculture. The widespread use of antibiotics in shrimp aquaculture to treat bacterial diseases has raised concerns about antibiotic resistance. As a result, alternative treatments, such as plant extract phytochemicals are being explored to mitigate these risks. This study aims to identify promising biologically active compounds from garlic (Allium sativum) that can inhibit the virulent protein thermolabile hemolysin of V. alginolyticus, which causes shrimp vibriosis. Various computational approaches, including molecular docking, pharmacokinetic analysis, and molecular dynamics simulation, were conducted to predict the compounds that can inhibit the phospholipase and hemolysis activities of the thermolabile hemolysin protein. Out of thirty-five compounds from A. sativum, protopine (CID 4970), gibberellin A7 (CID 92782), and gibberellic acid (CID 6466) demonstrated the strongest binding affinities, with scores of -9.4, -8.0, and -7.4 kcal/mol, respectively. Pharmacokinetic and toxicity analyses showed favorable drug-like properties for gibberellin A7 and gibberellic acid with no violations. Molecular dynamics simulations demonstrated that gibberellin A7 and gibberellic acid exhibited the highest stability over 100 nanoseconds. The investigation shows that gibberellin A7 and gibberellic acid from A. sativum have the potential to inhibit the virulent activity of thermolabile hemolysin. However, the study needs further in-vitro and in-vivo analysis to test our predicted results.

Gibberellic acid and 6-benzylaminopurine delays yellowing of pak choi (Brassica rapa subsp. chinensis) by inhibiting lipid peroxidation and chlorophyll degradation

Gibberellic acid and 6-benzylaminopurine delays yellowing of pak choi (Brassica rapa subsp. chinensis) by inhibiting lipid peroxidation and chlorophyll degradation

Effects of hormones on the growth and metabolite production of Amphidinium carterae under carbon sufficient and carbon limited conditions

The dinoflagellate Amphidinium carterae produces valuable fatty acids, pigments, and bioactive polyketides (e.g., amphidinols). Despite recent advances in its intensive cultivation, challenges remain that justify further work. This study explored the effects of phytohormone supplementation on growth and metabolism using a One Strain Many Compounds (OSMAC) approach. Auxins, cytokinins, jasmonates, amines, abscisic acid, gibberellic acid, and other signaling molecules were screened in batch cultures. Synthetic auxin 2-naphthoxyacetic acid (BNOA) at a final concentration of 14.84 μM (3 mg/L) emerged as the most stimulant. On a small scale, BNOA increased biomass productivity by up to 32 % and hemolytic activity in terms of productivity by 50 %. Scaling up in 10 L bubble column photobioreactor cultures with the addition of BNOA, but without CO2 supplementation, resulted in levels of amphidinol production comparable to those achieved with CO2 addition. Compared to the control without BNOA, BNOA cultures generated 2.2-fold more biomass during the stationary growth phase, and amphidinol production increased fourfold per unit of biomass. This work reveals that the addition of exogenous phytohormones such as BNOA can sustain the production of valuable metabolites in A. carterae, eliminating the need for additional CO2 and its associated costs. This promising approach highlights the potential of hormone supplementation as a cost-effective and efficient cultivation strategy for dinoflagellate bioprocesses.

Elevated CO2 alleviates negative impacts of high temperature and salinity on phytohormones, photosynthesis, and redox reactions in leaves of Caragana korshinskii kom.

In this research, we sought to investigate how high temperature, salinity, and CO2 affect endogenous phytohormones, photosynthesis, and redox homeostasis in Caragana korshinskii Kom (C. korshinskii) leaves, as well as to comprehensively evaluate the plant's physiological response to multiple environmental stressors. The elevated temperature (e[T]), elevated Na+ (e[Na]), and elevated temperature and Na+ (e[T-Na]) treatments increased abscisic acid (ABA) and reduced zeatin-riboside (ZR), indole-3-acetic acid (IAA), and gibberellic acid (GA3). These changes induced stomatal closure, and the subsequent reduction in photosynthetic rate triggered the generation of superoxide anion (O2·-) and hydrogen peroxide (H2O2). In response, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity increased, and free proline and total soluble sugars were accumulated. However, membrane lipid peroxidation was still aggravated. Under elevated CO2 (e[CO2]), the dramatic hormonal fluctuations and photosynthetic inhibition resulting from e[T], e[Na], and e[T-Na] were alleviated. Moreover, e[CO2] reduced ROS generation caused by e[T], e[Na], and e[T-Na], and stabilized antioxidant enzyme activities and non-enzymatic compound concentrations. Compared with e[T], e[Na], and e[T-Na], the increased malondialdehyde (MDA) content was effectively alleviated under elevated CO2 and temperature (e[CO2-T]), elevated CO2 and Na+ (e[CO2-Na]), and elevated CO2, temperature, and Na+ (e[CO2-T-Na]). Overall, our research suggest that e[CO2] may alleviate the negative impacts of e[T] and e[Na] on plant physiology.

Estratégias para a fixação e desenvolvimento de frutos da mangueira ‘Keitt’ cultivada no semiárido

ABSTRACT: The mango tree presents a high level of fruit abscission, which is increased in semiarid regions due to environmental stress. The use of biostimulants and phytoregulators has shown to be a promising strategy to improve fruit setting. Thus, the present study defined the best strategy for setting and development of the fruit, with the application of phytoregulators and biostimulants on the ‘Keitt’ mango tree, cultivated in the São Francisco Valley. Two experiments were performed. In experiment 1, a randomized block design was used, with four treatments T1: control, T2: gibberellic acid (AG3) + 2,4-dichlorophenoxyacetic acid (2,4-D), T3: AG3 + 2,4-D+Benzyladenine, T4: Biostimulant + CoMo® (sources of cobalt and molybdenum). In experiment 2, the factorial scheme (2 ×3 + 1) distributed in randomized blocks was established, corresponding to two forms of potassium fertilization (recommended and adjusted), three gibberellin concentrations (0, 10 and 20 mg L-1) and additional treatment (control - recommended potassium fertilization and no setting strategy). The variables analyzed include the relative number of fruits, the number of fruits for domestic and foreign markets, productive potential, production, productivity, fruit volume, fruit mass, and the yield of peel, pulp and stone. The application of 10 mg L-1 AG3 + 10 mg L-1 2,4-D + 10 mg L-1 Benzyladenine in full flowering of the ‘Keitt’ mango tree, increased the setting and the production of the fruit. Regardless of fertilization, sequential applications at 10 or 20 mg L-1 of AG3 proved to be an effective strategy to produce ‘Keitt’ mango tree. Adjusted potassium fertilization and the application at 10 mg L-1 of AG3 promotes the production of fruits with greater mass and volume.

Safflower seeds development: physical changes and the role of gibberellic acid, light, and temperature

Safflower seeds development: physical changes and the role of gibberellic acid, light, and temperature

Seed germination of the medicinal plant Ferula gigantea

Ferula gigantea is a perennial herb valued for its medicinal and ornamental properties. The declining survival rate of F. gigantea in its natural habitat has prompted research on seed germination to aid relocation and conservation efforts. Here, we examined seed morphology through controlled experiments and investigated the impact of gibberellic acid (GA3) soaking and low-temperature stratification on seed germination. A 90-day low-temperature stratification period yielded the highest germination of 86.7%. In conclusion, pre-sowing low temperature stratification for 90 days is an effective method for improving seed germination in F. gigantea.

The Effect of Seed Priming Using Giberellic Acid (GA3) on Growth of Groundnut (Arachis hypogaea L.) and Lurik Groundnut (Arachis hypogaea L. var. Lurik)

Seed priming is a technique for treating seeds before germination to improve the quality of the plants produced. Seed priming can be done by soaking the seeds in various solutions, including hormone solutions. Groundnut (Arachis hypogaea L.) is the second most important commodity in Indonesia for both common and striated groundnut. This research aims to determine the effect of seed priming using the hormone gibberellic acid on the vegetative growth of peanuts and striated peanuts. This research used a completely randomized design with a factorial pattern; the first factor is variation in the type of peanut; The second factor is the variation in gibberellic acid concentration for seed priming, namely 0 ppm (only distilled water), 100 ppm, 200 ppm, 300 ppm and 400 ppm and without priming. Each treatment was carried out in 3 repetitions. The variables observed were plant wet weight, plant dry weight, chlorophyll content, number of leaves, shoot:root ratio. Quantitative data were analyzed using Analysis of Variance (ANOVA) and DMRT with a confidence level of 95%. The results of the research showed that seed priming treatment using the gibberellic acid hormone had a significant effect on the wet weight and dry weight of the plants; shoot:root ratio, and chlorophyll content of peanut and striated peanut leaves. Seed priming treatment using the hormone gibberellic acid had no significant effect on the number of leaves of ordinary peanuts and striated peanuts.

Cannabis sativa: Monoecious species and Hermaphroditism: Feminized seed production- A breeding effort

Cannabis sativa L. is a dioecious wind-pollinated, although monoecious plants (male and female flowers on same plant) can occur in some population or developed by breeding efforts. Monoecious species have many advantages in the agricultural and industrial sectors due to the self-pollination and minimum variation in cannabinoid content from generation to generation. Monoecious species of cannabis also play an important role in the production of feminized seed production. Production of all female seed requires induction of female plants to develop male flowers that produce genetically female pollen. The aim of the cannabis commercial growers would like to access the feminized seed to produce all-female crops. Exogenous application of plant growth regulators can modify or reverse sex morphology in plants. There are a number of solutions that can be sprayed on female plants to create male pollen sacs: benzothiadiazole, gibberellic acid, silver thiosulphate, silver nitrate, and colloidal silver. Silver thiosulfate (STS) is the most effective compound for inducing sex reversal and feminizing seeds in high-THC cannabis cultivars. A hermaphrodite flower is one that has both staminate (male) and pistillate (female) floral structures on the same plant. A hermaphrodite flower is in the form of banana-shaped male anthers that emerge from the female flowers in small bunches, changing from green to a pale yellow as they develop. However, plants grown from feminized seeds are more likely to become hermaphrodites. The development of male anthers within the female inflorescence is known as hermaphrodite. Hermaphroditism is due to physical or chemical stress.

The effect of foliar spraying of naphthalene acetic acid, gibberellic acid, kinetin, putrescine and salicylic acid on physicochemical properties of ‘Shahabi’ date fruit

Growth regulators can improve the quality and production of fruit trees. This research was conducted over two successive years to evaluate the effect of preharvest sprays of growth regulators on the physicochemical properties of date palm fruit (Phoenix dactylifera cv. ‘Shahabi’) during khalal and tamar stages in a palm research station at Bushehr province. In the first year, fruit bunches of these trees were sprayed at the kimri stage, and in the second year at the kimri and hababouk + kimri stages, using NAA (100 mg/L), GA3 (100 mg/L), KI (100 mg/L), SA (50 mg/L), Put (1.288 × 103 mg/L), and distilled water as the control. Foliar spraying of ‘Shahabi’ date clusters with all plant growth regulators at the kimri stage did not have significant effects on traits such as length, diameter, weight and volume of the fruit compared to the control but, foliar spraying in the hababouk + kimri stage with NAA and to some extent Put caused a significant increase in these factors in the khalal and tamar stages. Foliar spraying with all growth regulators caused a significant increase in the weight of pulp in the khalal and tamar stages. With foliar application of Put, SA, GA3, and especially NAA, cluster weight and yield percent showed a significant increase compared to the control at the tamar stage. In general, the percentage of fruit drop in the foliar application of all growth regulators in the hababouk + kimri stage was significantly higher compared to the foliar application in the kimri stage. Foliar spraying in the kimri stage significantly reduced the fruit drop compared to the control but foliar application of NAA, GA3 and SA in the hababouk + kimri stage significantly increased the fruit drop compared to the control. Foliar spraying of all plant growth regulators in the kimri and hababouk + kimri stages caused a significant decrease in the percentage of TSS as well as the percentage of total carbohydrates compared to the control in the khalal and tamar stages. Foliar spraying with all plant growth regulators in the kimri and hababouk + kimri stages caused a significant increase in the TA percentage in khalal stage compared to the control.

Evaluation of seed dormancy-breaking techniques for enhancing germination potential, seedling growth, and vigour of Carissa carandas L.

Carissa carandas L. is a versatile evergreen shrub of the Apocynaceae family and its fruit is rich in vitamins and antioxidants. It is commonly propagated by seeds, which are characterized by low germination rates due to the presence of a hard seed coat that causes physical dormancy and limits water absorption and gas exchange. In this study, the effects of different dormancy-breaking treatments viz., chemical treatment with potassium nitrate and thiourea at two concentrations (1% and 2%), hormonal therapy with gibberellic acid (GA3) at two concentrations (500 and 1000 ppm) and physical treatments (hot water and simple water immersion) were investigated on germination and seedling growth using a Randomized Block Design (RBD) with three replications and the statistical significance of each treatment was tested at the five percent probability level (p ? 0.05). Key germination indices, seedling growth parameters, and seedling vigour were observed. Among all treatments, 2% KNO3 was most effective in breaking seed dormancy that achieved significantly higher (86.33%) germination with accelerated completion of germination in 18 days and the highest (4.80) mean daily germination (MDG). Thiourea 2% attained a germination percentage of 82.91% and MDG of 4.36 while GA3 treated seeds had a lower germination percentage and MDG than KNO3 and thiourea treatments. The significantly highest seedling length vigour index (LVI) of 1085.1 and weight vigour index (WVI) of 12.67 were also obtained in 2% KNO3 treated seeds which was followed by 2% thiourea with LVI of 1003.6 and WVI 10.12 . Both LVI and WVI were significantly lower in GA3 treatments compared to KNO3 and thiourea treatments. The significantly lowest germination percentage (61.19%), MDG (2.78), LVI (575.8), and WVI (3.67) were recorded in the control. This study offers valuable insights into the efficient techniques for seed dormancy breaking and optimizing seed propagation techniques for C. carandas L.

Effects of Marquandomyces marquandii SGSF043 on the Germination Activity of Chinese Cabbage Seeds: Evidence from Phenotypic Indicators, Stress Resistance Indicators, Hormones and Functional Genes

In this study, the effect of Metarhizium spp. M. marquandii on the seed germination of cabbage, a cruciferous crop, was investigated. The effects of this strain on the seed germination vigor, bud growth and physiological characteristics of Chinese cabbage were analyzed by a seed coating method. The results showed the following: (1) The coating agent M. marquandii SGSF043 could significantly improve the germination activity of Chinese cabbage seeds. (2) The strain concentration in the seed coating agent had different degrees of regulation on the antioxidase system of the buds, indicating that it could activate the antioxidant system and improve the antioxidant ability of the buds. (3) When the concentration of M. marquandii SGSF043 was 5.6 × 106 CFU/mL (average per grain), the effect of M. marquandii SGSF043 on the leaf hormones Indole Acetic Acid (IAA), Gibberellic Acid (GA) and Abscisic Acid (ABA) of Chinese cabbage seedlings was significantly higher than that of other treatment groups, indicating that the strain could optimize the level of plant hormones. (4) M. marquandii SGSF043 could induce the expression of stress-resistance-related genes in different tissue parts of Chinese cabbage and improve the growth-promoting stress resistance of buds. This study showed that M. marquandii SGSF043 could not only improve the germination vitality of Chinese cabbage seeds but also enhance the immunity of young buds. The results provide a theoretical basis for the application potential of Metarhizium marquandii in agricultural production.

Enhancing the success rate of semi-micrografted mandarin orange (Citrus reticulata), variegated chinotto sour orange (Citrus myrtifolia foliis variegates) and sour orange (Citrus aurantium L.) while reducing incidences of the Tristeza Virus and Fusarium oxysporum in grafted plants

The primary vitamin C source in our diet comes from citrus fruits. It is rich in antioxidants and anti-inflammatory properties, which are vital to disease prevention. Widely grown worldwide, citrus fruits are valued for their medicinal and economic benefits. Grafting is the commonly used method for propagating citrus, as seed propagation results in diverse progenies. Therefore, to maintain the true-to-type characters of the mother plant, it is propagated clonally through bud-grafting. However, one drawback of grafting is the potential transmission of diseases. To address this, an in-vitro micrografting technique was developed to prevent disease transmission during plant propagation. However, this technique requires modification due to its high cost, demand for skilled labour, and long propagation time. This study introduced a cost-effective, labour-efficient, and timesaving-enhanced semi-micrografting technique. Various treatments were evaluated based on graft success percentage, and the results were analysed using a one-way analysis of variance and Tukey’s honestly significant difference test. The results revealed that the combination of 10 mgL-1 gibberellic acid, 10 mg L-1 2,4–dichlorophenoxyacetic acid, 500 mg L-1 ascorbic acid, 50 mM calcium chloride and 30 μL of Ceylon cinnamon leaf oil was the best treatment, as it had the highest grafting success rate (62.22 ± 5.091%) compared to the other treatments. The study demonstrated that the enhanced semi-micrografting technique could significantly decrease the incidence of Citrus tristeza virus and Fusarium oxysporum diseases in grafted sour orange, mandarin orange, and variegated Chinotto sour orange plants, achieving disease reductions of 96% and 86%, respectively while maintaining a high graft success rate.

Effect of IAA, GA3, Salicylic Acid and Tebuconazole on Growth, Productivity and Economics of Linseed (Linum usitatissimum L.) Cultivation under Rainfed Conditions

Background: The use of plant growth regulators (PGRs) to manipulate and enhance the physiological and biochemical processes in plants is a potential area in crop production, to mitigate the many barriers imposed by genetics and environment especially for oilseed crop like linseed which is generally grown in high-risk environments under input starved conditions resulting in very low yields. Methods: Field investigations were conducted during the rabi seasons of 2019 and 2020 to study the response of linseed crop (Linum usitatissimum L.) to foliar applications of PGRs (plant growth regulators) under rainfed conditions. The trials were laid out in randomized block design with seven (7) treatments viz., control (water spray), Indole-3-Acetic Acid (IAA) @ 1 mg/l, IAA @ 2 mg/l, Gibberellic Acid (GA3) @ 200 mg/l, GA3 @ 400 mg/l, Salicylic Acid @ 75 mg/l and Tebuconazole @ 0.1%. Result: Results showed that the treatments IAA @ 1.0 and 2.0 mg/l and GA3 @ 200 and 400 mg/l were at par with each other and recorded significant higher seed yields ranging from 1270.72 kgs/ha to 1180.17 kgs/ha during 2019 and 1244.23 kgs/ha to 1135.10 kgs/ha during 2020. Application of IAA @ 2.0 mg/l was found to record the highest benefit cost ratio (BCR) [2.72 and 2.66 during 2019 and 2020 respectively] as well as economic efficiency (210.12 and 208.70 Rs./ha/day during 2019 and 2020 respectively).

Применение эндофитных микроорганизмов для интенсификации ростовых процессов сельскохозяйственных культур

Increasing the yield of wheat, barley, and oats is a pressing issue. It largely depends on soil fertility. Mineral fertilizers, however, may be ineffective and unsustainable. As a result, microorganisms seem to be a promising alternative. The authors isolated endophytic microorganisms with growth-stimulating properties and assessed their effect on the growth rate of wheat, barley, and oats in laboratory conditions. The research involved spring soft wheat of the Sibirsky Alyans variety, spring oats of the Maruchak variety, spring barley of the Nikita variety, and standard bacterial strains (Azospirillum brasilense B-11094, Azotobacter chrococcum B-8739). The isolated bacteria were identified using a Vitex 2 Compact automatic microbiological analyzer. The production potential for indole-3-acetic and gibberellic acids was assessed spectrophotometrically. The nitrogen fixation potential was determined using a Rapid N Cube. The phosphate-solubilizing potential was tested on a calcium phosphate medium. The effect of the most promising strains on the growth rate was assessed in laboratory conditions. Seven isolates of endophytic microorganisms were identified as Pantoea allii Tri, Bacillus subtilis Tri 2, Bacillus subtilis Ave 1, Pantoea allii Ave 2, Bacillus subtilis Hor 1, Bacillus subtilis Hor 2, and Bacillus subtilis Hor 3. The most promising growth promoters ranged as follows. Bacillus subtilis Ave 1 fixed 790 μg/mL nitrogen, solubilized phosphates with index 1.60, and produced 7100 μg/mL indolyl-3-acetic acid and 343 μg/mL gibberellic acid. Bacillus subtilis Hor 1 fixed 760 μg/mL nitrogen, solubilized phosphates with index 1.44, and synthesized 4490 μg/mL indolyl-3-acetic acid and 409 μg/mL gibberellic acid. Bacillus subtilis Ave 1 demonstrated the greatest growth-stimulating activity. Bacillus subtilis Ave 1 could synthesize phytohormones, fix atmospheric nitrogen, and solubilize phosphates, which indicated good agricultural prospects. The strain increased the length of shoots and roots in wheat and barley, as well as boosted germination and shoot length in oats.

The Effects of Different Doses of Zeatin, Kinetin and Gibberellic Acid Biostimulants Applied during the Seedling Development Period of Peppermint (Mentha Piperita L.) on Growth and Biochemical Parameters

This study aimed to evaluate the impact of varying doses of Zeatin, Kinetin, and Gibberellic Acid biostimulants on the growth and biochemical parameters of Mentha piperita L. Conducted in a greenhouse with three replications using a "Completely Randomized Experimental Design" design, the experiment assessed seedling and root lengths, fresh and dry weights of seedlings and roots, total phenolic content, and antioxidant activity (CUPRAC and FRAP). The results revealed that biostimulant applications significantly increased all growth and biochemical parameters compared to the control. Gibberellic acid at 200 mg/l produced the longest seedlings, while Kinetin at 50 mg/l resulted in the longest roots. The highest antioxidant activity (FRAP) and total phenolic content were observed with the 40 mg/l dose of Zeatin.