Gibberellic Acid Research Articles

Melatonin and Gibberellin Employing to Mitigate Heat Stress Effects on “Canino” Apricot

The fruit yield of apricot trees may decrease as a result of temperature stress. Through improving growth, productivity, and fruit quality, some compounds may play a significant part in resolving that issue. Therefore, this study was conducted during two successive growing seasons (2017 and 2018) in order to lessen the effects of heat stress on the production and fruit quality of Canino apricot trees cultivated on the farm of the Horticulture Research Station at El Kanater El Khayreia, Egypt, by foliar spray of hormonal substances and antioxidants i.e. (melatonin “MEL” or gibberellic acid” GA3 “each at concentration (25 mg/L) at pre-dormancy stage. It could be concluded that spraying Canino apricot trees at pre-dormancy stage (August) with both of GA3 and MEL enhanced the vegetative growth, as well as it improved flower quality compared with untreated control during the two cultivated seasons, also, melatonin improved growth and fruit set, yield, and fruit quality, followed by gibberellic acid compared with Control.

Isolation and Characterization of Arsenic-Tolerable Bacteria from Groundwater and Their Implementation on Rice Seedling's Shoot and Root Enhancement.

Arsenic exerts detrimental impacts on primary metabolism in plants, leading to reduced crop yield. Some arsenic-resistant plant growth-promoting bacteria (PGPB) help plants by providing some plant hormones to sustain their growth and development under arsenic stress. Here, seven different species of Bacillus were isolated from arsenic-contaminated groundwater of West Bengal, India. Those species were capable of growing in the presence of > 3.12g/L arsenate (AsV) and > 0.65g/L arsenite (AsIII) salts and also resist different heavy metals like Cu2+, Fe2+, Co2+, Zn2+, Pb2+, etc. They were susceptible to multiple groups of antibiotics like beta-lactam, aminoglycosides, etc. All species were capable of detoxifying arsenite and influenced rice seedlings' growth in the presence of arsenic salts by their capabilities likenitrogen-fixing ability, phosphate solubilization, indole 3-acetic acid (IAA), gibberellic acid (GA), proline production, etc. Most species helped enhance root and shoot lengths under arsenic stress. These primary findings suggest that those Bacillus spp. could be used as potential bio-fertilizers in arsenic-contaminated agricultural fields.

The potential role of gibberellic acid in regulating photosynthetic pigments, fruit quality and antioxidant enzymes in sweet lime Citrus limetta Risso

The potential role of gibberellic acid in regulating photosynthetic pigments, fruit quality and antioxidant enzymes in sweet lime Citrus limetta Risso

The GRAS transcription factor PtrPAT1 of Poncirus trifoliata functions in cold tolerance and modulates glycine betaine content by regulating the BADH-like gene

Abstract GRAS, termed after GAI (gibberellic acid insensitive), RGA (repressor of GA1), and SCR (scarecrow), is a plant-specific transcription factor crucial for plant development and stress response. However, understanding of the functions played by the GRAS members and their target genes in citrus is limited. In this study, we identified a cold stress-responsive GRAS gene from Poncirus trifoliate, designated as PtrPAT1, by yeast one-hybrid library screening using the promoter of PtrBADH-l, a betaine aldehyde dehydrogenase (BADH)-like gene. PtrPAT1, belonging to the PAT1 subfamily, was localized in the nucleus and plasma membrane, exhibited transactivation activity and showed a remarkable upregulation under cold stress. Overexpression of PtrPAT1 elevated BADH activity, increased glycine betaine (GB) accumulation and conferred enhanced cold tolerance in transgenic tobacco plants compared with wild type, while downregulation in trifoliate orange by virus-induced gene silencing (VIGS) resulted in opposite trends. Furthermore, the activities of two antioxidant enzymes, including peroxidase (POD) and superoxide dismutase (SOD), were significantly increased in the overexpression plants, but remarkably decreased in the VIGS line, consistent with accumulation patterns of the reactive oxygen species (ROS). PtrPAT1 was demonstrated to interact with and activate the PtrBADH-l promoter through the putative PAT1-binding motif with the core sequence of TTTCATGT, indicating that PtrBADH-l is a target gene of PtrPAT1. Taken together, these results demonstrate that PtrPAT1 positively affects cold tolerance through the regulation of GB biosynthesis by modulating PtrBADH-l expression.

Role of Gibberellic Acid (GA3) in Improving Salt Stress Tolerance of Wheat (Triticum avestivum)

Salinity is a critical environmental factor that adversely affects crop growth and productivity. This study aimed to evaluate the effects of gibberellic acid (GA3) on germination, shoot length, root length, and biomass of two wheat cultivars (Demirhan and Fazılbey) under varying levels of salt stress (0, 5, and 10 dS/m NaCl). GA3 was applied at concentrations of 100 and 200 ppm to assess its potential in alleviating the adverse effects of salinity. The results revealed that GA3 significantly improved germination percentage, shoot length, and root length in both cultivars, with the Demirhan cultivar showing more pronounced responses under higher salt stress. A biplot analysis highlighted the interaction between GA3 treatment, salinity levels, and cultivar performance, confirming the positive role of GA3 in mitigating the detrimental effects of salinity. These findings suggest that GA3 can be an effective strategy for enhancing wheat growth in saline soils. Further studies are recommended to optimize GA3 concentrations and evaluate its long-term effects under field conditions.

Exogenously Applied Gibberellic Acid Alters Cannabinoid Profile in Cannabis sativa L.

Cannabis sativa (C. sativa L.) has garnered significant attention worldwide due to its widespread use as a pharmaceutical agent. With the increasing clinical application of C. sativa and cannabinoid therapeutics, there is strong interest in the development of superior plant varieties and optimisation of growth conditions to enhance secondary metabolite yield. Our RNA sequencing analysis revealed differential expression of hormone-related transcripts in developing C. sativa trichomes, suggesting the involvement of hormone signalling pathways in cannabinoid production. Leveraging the potency of exogenous hormones on plants, this study sought to determine if the application of cytokinin (CK), gibberellic acid (GA) and jasmonic acid (JA) modified trichome morphology and the cannabinoid profile over an 8-week period following the induction of flowering. Exogenous hormone application led to alterations in trichome morphology, with each treatment significantly reducing trichome head width by the final week of assessment. Interestingly, GA application also resulted in a significant reduction in the concentration of Δ-9-tetrahydrocannabinol (THC), Δ-9-tetrahydrocannabinolic acid (THCA), cannabidiol (CBD) and cannabidiolic acid (CBDA) by week 8 post floral induction, however, JA and CK treatment did not consistently modulate the accumulation of these cannabinoids. The minor cannabinoids, cannabidivaranic acid (CBDVA), cannabicyclolic acid (CBLA), cannabicyclol (CBL), cannabichromene (CBC), cannabigerolic acid (CBGA) and cannabigerol (CBG), were also affected by hormone treatments, with varying degrees of accumulation observed. These findings underscore the intricate interplay between phytohormones and secondary metabolite biosynthesis in C. sativa. Our study highlights the potential of hormone modulation as a strategy to enhance cannabinoid yield and offers some insights into the regulatory mechanisms governing cannabinoid biosynthesis in C. sativa trichomes.

Metallothionein family genes in kiwifruit: characterization and determining their roles in plant’s response to different stresses

Kiwifruit growth and development are severely affected by various biotic and abiotic stresses, especially cold stress and the bacterial disease caused by Pseudomonas syringae pv. actinidiae (Psa). Metallothioneins (MTs) are a group of cysteine-rich proteins that play crucial roles in stress response, metal detoxification, and homeostasis in plants. However, the protective role of these MTs in kiwifruit remains to be elucidated. In the present study, four AcMT genes were identified in the Hongyang kiwifruit genome, namely, two Type 2 isoforms (AcMT2 and AcMT2a) and two Type 3 isoforms (AcMT3a and AcMT3b) located separately on four different chromosomes. The hormones and stress response cis-elements within the promoter regions of these AcMTs were characterized. It was revealed that the four AcMT genes exhibited different expression patterns in different tissues: AcMT2 and AcMT2a were expressed at much higher levels in the fruit, male flower, female flower, root, and bark, while AcMT3a was expressed mainly in the fruit and AcMT3b was expressed highly in the bark. The expression patterns of these AcMT genes after exposure to Psa infection and different phytohormones, including gibberellic acid A3(GA3), ethylene (ET), and abscisic acid (ABA), were evaluated. It was revealed that in response to Psa infection, the main AcMTs in each tissue (those with expression levels higher compared to the other MTs in that tissue) were downregulated during the early stage in kiwifruits, followed by a recovery phase. In addition, most AcMTs were downregulated after exposure to ET and GA3, while type 2 AcMTs (AcMT2 and AcMT2a) were upregulated after treatment with ABA. The overexpression of AcMTs in Escherichia coli presented a higher tolerance to H2O2, heavy metals, low temperature, and high temperature. Collectively, these findings demonstrated the protective roles of AcMTs in terms of stress resistance conferred through plant hormone-related signal pathways.

Widespread production of plant growth-promoting hormones among marine bacteria and their impacts on the growth of a marine diatom

BackgroundReciprocal exchanges of metabolites between phytoplankton and bacteria influence the fitness of these microorganisms which ultimately shapes the productivity of marine ecosystems. Recent evidence suggests that plant growth-promoting hormones may be key metabolites within mutualistic phytoplankton-bacteria partnerships, but very little is known about the diversity of plant growth-promoting hormones produced by marine bacteria and their specific effects on phytoplankton growth. Here, we aimed to investigate the capacity of marine bacteria to produce 7 plant growth-promoting hormones and the effects of these hormones on Actinocyclus sp. growth.ResultsWe examined the plant growth-promoting hormone synthesis capabilities of 14 bacterial strains that enhance the growth of the common diatom Actinocyclus. Plant growth-promoting hormone biosynthesis was ubiquitous among the bacteria tested. Indeed all 14 strains displayed the genomic potential to synthesise multiple hormones, and mass-spectrometry confirmed that each strain produced at least 6 out of the 7 tested plant growth-promoting hormones. Some of the plant growth-promoting hormones identified here, such as brassinolide and trans-zeatin, have never been reported in marine microorganisms. Importantly, all strains produced the hormone indole-3 acetic acid (IAA) in high concentrations and released it into their surroundings. Furthermore, indole-3 acetic acid extracellular concentrations were positively correlated with the ability of each strain to promote Actinocyclus growth. When inoculated with axenic Actinocyclus cultures, only indole-3 acetic acid and gibberellic acid enhanced the growth of the diatom, with cultures exposed to indole-3 acetic acid exhibiting a two-fold increase in cell numbers.ConclusionOur results reveal that marine bacteria produce a much broader range of plant growth-promoting hormones than previously suspected and that some of these compounds enhance the growth of a marine diatom. These findings suggest plant growth-promoting hormones play a large role in microbial communication and broaden our knowledge of their fuctions in the marine environment.4YJWCKdNErspcm2bUDNM6tVideo

Exploring the synergistic benefits of biochar and gibberellic acid in alleviating cadmium toxicity

Cadmium (Cd) toxicity significantly threatens agricultural productivity and food safety. Developing effective strategies to enhance plant tolerance to Cd stress is essential. This study investigates the synergistic effects of biochar (BC) and gibberellic acid (GA3) on mitigating Cd toxicity in maize (Zea mays), focusing on their impact on oxidative stress markers and antioxidant enzyme activities. Soil samples were collected from the Cholistan Institute of Desert Studies (CIDS) and analyzed for trace metal ions and other properties. Biochar was produced from fruit and vegetable waste, washed, washed, deashed, and mixed with 10 ppm GA3. FH-1036 hybrid maize seeds were sterilized and planted in pots containing soil with varying Cd levels (0, 8, and 16 mg Cd/kg soil). Twelve treatments were established, including control, GA3, BC, and their combinations under different Cd stress levels. Plants were irrigated to maintain 60% field capacity and harvested at the V10 growth stage. Hydrogen peroxide (H2O2) contents and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were measured in roots, stems, and leaves. Statistical analysis was performed using OriginPro 2021, with ANOVA and Fisher’s LSD test used to determine significant differences. GA3 and BC treatments significantly reduced H2O2 levels in maize roots, stems and leaves under Cd stress. The combined treatment of GA3 + BC showed the most significant reduction in H2O2 levels across all plant parts, reducing root H2O2 by 50%, stem H2O2 by 55%, and leaf H2O2 by 53% under severe Cd stress (16 mg Cd/kg). SOD activity increased under non-stress conditions but decreased under Cd stress, with the highest activity observed in the combined treatment. POD activity followed a similar pattern, with GA3 + BC treatment resulting in the most significant increases under non-stress conditions and the least reductions under Cd stress. CAT activity showed substantial increases with GA3 + BC treatment, particularly under severe Cd stress, with a notable rise over the control. APX activity also exhibited enhancements with GA3 and BC treatments, especially in the combined treatment under various Cd stress levels. This study highlights the potential of combined BC and GA3 treatments in improving Cd stress tolerance in maize. Future research should focus on field trials and the long-term impacts of these treatments on crop productivity and soil health.

The Influence of Different Factors on the Metabolism of Capsaicinoids in Pepper (Capsicum annuum L.)

Pepper is a globally cultivated vegetable known for its distinct pungent flavor, which is derived from the presence of capsaicinoids, a class of unique secondary metabolites that accumulate specifically in pepper fruits. Since the accumulation of capsaicinoids is influenced by various factors, it is imperative to comprehend the metabolic regulatory mechanisms governing capsaicinoids production. This review offers a thorough examination of the factors that govern the metabolism of capsaicinoids in pepper fruit, with a specific focus on three primary facets: (1) the impact of genotype and developmental stage on capsaicinoids metabolism, (2) the influence of environmental factors on capsaicinoids metabolism, and (3) exogenous substances like methyl jasmonate, chlorophenoxyacetic acid, gibberellic acid, and salicylic acid regulate capsaicinoid metabolism. The findings of this study are expected to enhance comprehension of capsaicinoids metabolism and aid in the improvement of breeding and cultivation practices for high-quality pepper in the future.

Comparison between bacterial bio-formulations and gibberellic acid effects on Stevia rebaudiana growth and production of steviol glycosides through regulating their encoding genes

Stevia rebaudiana is associated with the production of calorie-free steviol glycosides (SGs) sweetener, receiving worldwide interest as a sugar substitute for people with metabolic disorders. The aim of this investigation is to show the promising role of endophytic bacterial strains isolated from Stevia rebaudiana Egy1 leaves as a biofertilizer integrated with Azospirillum brasilense ATCC 29,145 and gibberellic acid (GA3) to improve another variety of stevia (S. rebaudiana Shou-2) growth, bioactive compound production, expression of SGs involved genes, and stevioside content. Endophytic bacteria isolated from S. rebaudiana Egy1 leaves were molecularly identified and assessed in vitro for plant growth promoting (PGP) traits. Isolated strains Bacillus licheniformis SrAM2, Bacillus paralicheniformis SrAM3 and Bacillus paramycoides SrAM4 with accession numbers MT066091, MW042693 and MT066092, respectively, induced notable variations in the majority of PGP traits production. B. licheniformis SrAM2 revealed the most phytohormones and hydrogen cyanide (HCN) production, while B. paralicheniformis SrAM3 was the most in exopolysaccharides (EPS) and ammonia production 290.96 ± 10.08 mg/l and 88.92 ± 2.96 mg/ml, respectively. Treated plants significantly increased in performance, and the dual treatment T7 (B. paramycoides SrAM4 + A. brasilense) exhibited the highest improvement in shoot and root length by 200% and 146.7%, respectively. On the other hand, T11 (Bacillus cereus SrAM1 + B. licheniformis SrAM2 + B. paralicheniformis SrAM3 + B. paramycoides SrAM4 + A. brasilense + GA3) showed the most elevation in number of leaves, total soluble sugars (TSS), and up-regulation in the expression of the four genes ent-KO, UGT85C2, UGT74G1 and UGT76G1 at 2.7, 3.3, 3.4 and 3.7, respectively. In High-Performance Liquid Chromatography (HPLC) analysis, stevioside content showed a progressive increase in all tested samples but the maximum was exhibited by dual and co-inoculations at 264.37% and 289.05%, respectively. It has been concluded that the PGP endophytes associated with S. rebaudiana leaves improved growth and SGs production, implying the usability of these strains as prospective tools to improve important crop production individually or in consortium.

Enhancing yield and economics of banana cultivar Rasthali (Silk-AAB) through bunch spray of growth regulators and nutrients

Aim: Poor finger filling is often observed in Rasthali bananas, which results in low fruit yield. Hence, different growth regulators and nutrients were sprayed at various concentrations to enhance the yield and economics of Rasthali banana. Methodology: The experiment was conducted at Dharumathupatti village, Dindigul district, Tamil Nadu during 2022 and 2023 in a Randomized Block Design with eight treatments, replicated thrice. The treatments included Gibberellic acid @ 50 ppm (T1), NAA @ 50 ppm (T2), 2,4-D @ 25 ppm (T3), Ethephon @ 100 ppm (T4), Urea @ 10000 ppm (T5), Potassium nitrate @ 10000 ppm (T6), Potassium sulphate @ 20000 ppm (T7) and Control (T8). The spraying was done twice; the first spray at emergence of the last hand and the second, one month after the first spray. The observations on various growth, bunch and finger parameters as well as the benefit: cost ratio (B:C ratio) were recorded. Results: T7 treatment produced the highest number of leaves (8.97) whereas T4 treatment registered the minimum number of days taken from last hand opening to harvest (98.67). The highest bunch, finger parameters and benefit-to-cost ratio were also recorded in T7 treatment. Interpretation: Potassium sulphate (20000 ppm) effectively enhanced the growth, yield and economics of Rasthali banana. Key words: Banana cultivar, Bunch spray, Growth regulator, Potassium, Yield

The impact of varying levels of Gibberellic Acid (GA3) on plant growth, flowering, flower quality, seed yield, and quality of Petunia(Petunia × hybrida Vilm.)

Petunia, a popular ornamental plant, is known for its vivid flowers and wide color range. Petunia has long been valued for its aesthetic appeal, but recent research has begun to shed light on its possible medicinal properties. Petunia × hybrida is widely recognized for its medicinal characteristics, phytochemical content, and potential health benefits. A research study was undertaken between the years 2021 and 2022. The field experiment was laid out in a randomized complete block design (RCBD), with 11 treatments replicated three times. The treatments included 10 GA3 concentrations from 25 to 250 ppm applied 45 days post-transplantation, along with control—Petunia cv. 'White' seedlings were transplanted in main plots with 30 × 30 cm spacing. Based on the results, it was noted that foliar feeding the leaves with 200 ppm GA3 produced notable outcomes in various characteristics. This treatment recorded a higher plant height (53.45 cm), spread (50.32 cm), and branches per plant (26.77 cm). It also minimized time to first flowering (78.81 days), 50 % flowering (96.67 days), and peak flowering (107.33 days). Furthermore, 200 ppm GA3 optimized flowering duration (123.47 days), flower diameter (6.76 cm), flowers per plant (405.60), seeded capsules per plant (367.13), and seeds per capsule (535.67). Seed yield was maximized at all levels: per plant (12.51 g), per plot (54.33 g), and per hectare (380.33 kg). Seed quality parameters also peaked, including 1000-seed weight (93.65 mg), germination (93.75 %), germination speed (10.59), seedling length (3.63 cm), and dry weight (0.331 mg). Vigor indices I (340.54) and II (30.99) were significantly higher, while seed electrical conductivity was significantly low (77.13 μSm-1) with this treatment.

Allelic variants confer Arabidopsis adaptation to small regional environmental differences.

Natural populations of Arabidopsis thaliana provide powerful systems to study the adaptation of wild plant species. Previous research has predominantly focused on global populations or accessions collected from regions with diverse climates. However, little is known about the genetics underlying adaptation in regions with mild environmental clines. We have examined a diversity panel consisting of 192 A. thaliana accessions collected from the Netherlands, a region with limited climatic variation. Despite the relatively uniform climate, we identified evidence of local adaptation within this population. Notably, semidwarf accessions, due to mutation of the GIBBERELLIC ACID REQUIRING 5 (GA5) gene, occur at a relatively high frequency near the coast and these displayed enhanced tolerance to high wind velocities. Additionally, we evaluated the performance of the population under iron deficiency conditions and found that allelic variation in the FE SUPEROXIDE DISMUTASE 3 (FSD3) gene affects tolerance to low iron levels. Moreover, we explored patterns of local adaptation to environmental clines in temperature and precipitation, observing that allelic variation at LA RELATED PROTEIN 1C (LARP1c) likely affects drought tolerance. Not only is the genetic variation observed in a diversity panel of A. thaliana collected in a region with mild environmental clines comparable to that in collections sampled over larger geographic ranges but it is also sufficiently rich to elucidate the genetic and environmental factors underlying natural plant adaptation.

Gibberellic Acid and Abscisic Acid Effects on Germination Across Arabidopsis Genotypes: Confirmation of Compound Identity and Genotypic Responses

It is well known that plant growth depends on the interaction of auxin and hormones, but whether different hormones have different effects on seed growth in different varieties is not fully understood. This study used a controlled experimental setup in which seeds from three different genotypes (assumed to be wild-type, abscisic acid (ABA) insensitive, and gibberellic acid (GA) deficient) were exposed to treatments of these compounds (labeled compounds A and B), as well as a control treatment using ethanol. Our results confirm the identities of Compound A as gibberellic acid and Compound B as abscisic acid through their consistent effects on seed germination. Gibberellic acid (Compound A) significantly enhanced germination across all genotypes. With the help of Gibberellic acid, GA-deficient genotype also showed a dramatic increase in germination rates which suggested a compensatory effect. Conversely, abscisic acid (Compound B) markedly inhibited germination, with the most pronounced effect observed in the wild-type genotype. The ABA-insensitive genotype demonstrated reduced susceptibility to Compound B, supporting its phenotypic characterization. The study highlights the key antagonistic role of gibberellic acid and abscisic acid in seed germination, providing valuable insights into defining genotypic-phenotypic interactions in plant responses to environmental and chemical signals.

The effect of different cytokinin and auxin source on micropropagation of Kalanchoe blossfeldiana

Micropropagation is widely used for vegetative propagation of many different ornamental and medicinal plant species under aseptic conditions. This technology has widespread practical applications irrespective of seasonal and time-space constraints. The present study aimed to design in vitro propagation using 1 8 different combinations of BAP, NAA, TDZ, and GA3 supplemented with commercial tea sugar at 30 g l-1 for micropropagation using leaf segments close to petiole of Kalanchoe blossfeldiana as explants and to find its efficiency for viable cultures. The results showed clear discrimination between regeneration on TDZ and BAP-supplemented regeneration cultures. Thus, both BAP-NAA and TDZ-NAA combinations were found suitable for micropropagation. the source medium affected the shoot regeneration and the rooting ability, irrespective of the culture of any shoot regeneration medium. These plantlets were rooted in 0.01-0.05 mg l-1 IBA. The study showed successful rooting under in vitro conditions using 1 ½ or 1×MS medium with 0.5 mg L-1 IBA. These rooted plantlets were then transferred to MS medium with 0.2 mg L-1 gibberellic acid and without BAP or with 0.1, 0.2, 0.5 mg l-1 TDZ and 0.1 mg l-1 NAA or without 0.1 mg L-1 NAA for adaptation. The results of the study are of great importance for K. blossfeldiana plant breeding studies and growers.

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.

Identification and functional characterization of the diterpene synthase family in Pogostemon cablin (Blanco) Benth

Pogostemon cablin (Blanco) Benth (Patchouli) is an aromatic herb extensively used in pharmaceutical and cosmetic industries. Sesquiterpenes are the characteristic constitutes in patchouli which are synthesized in the glandular trichomes on leaves and stems. Gibberellic acid (GA), a tetracyclic diterpenoid, plays a crucial role in the formation of glandular trichome. However, the diterpene biosynthesis remains largely unknown in patchouli. Here we identified a small diterpene synthases (diTPSs) family comprising three class II diTPSs (PatCPS1-3) and three class I diTPSs (PatKSL1 and PatGLS1-2). These diTPSs are functionally characterized using a yeast heterologous expression system. PatCPS1 was identified as an ent-copalyl diphosphate synthase (ent-CPS), in combination with PatKSL1, yield ent-kaurene, the precursor of GA, indicating their involvement in primary metabolism. PatCPS2 converted GGPP into (+)-8, 13-copalyl diphosphate (CPP). No activity was detected for PatCPS3, PatGLS1 and PatGLS2. Three ohnologs of PatCPS1 were further characterized to explore the possible functional differentiation of ent-CPS during the evolution of tetraploid hybrid patchouli genome. GC-MS analysis showed all ohnologs are functional ent-CPSs, demonstrating the functional conservation of PatCPS1 during evolution. Expression profiling by qRT-PCR showed PatCPS1 and PatKSL1 are ubiquitously expressed in all tissues, consistent with their involvement in primary metabolism. Conversely, PatCPS2 and PatCPS3 were predominantly expressed in the above ground parts, indicating a role in specialized metabolism. In summary, these findings clarify the early stages of GA biosynthesis in patchouli and provide gene elements for further metabolic engineering of sesquiterpenes via diterpenoids.

Effect of Plant Growth Regulators on Germination and Seedling Growth of Passiflora alata and Passiflora edulis

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.

Ocimum gratissimum mediated green synthesised iron oxide nanoparticles as a plausible nanofertilizer for peanut plant (Arachis hypogaea)

Exploring the potential of iron/iron oxide nanoparticles (IONPs) to act as fertilizer is an area of immense interest. This paper reports the green synthesis of IONPs using aqueous extract of Ocimum gratissimum leaves and its characterization with XRD, HRTEM and FTIR. This environmentally benign route avoids hazardous and toxic chemicals commonly employed in nanoparticle synthesis. The IONPs formed (Fe2O3) are stabilized by the phenolic and aromatic compounds found in the aqueous extract of Ocimum gratissimum and are of small crystallite size (5–30 nm). Peanut seedlings treated with these IONPs exhibited a superior growth performance at lower application rates (100 mg L−1), as evidenced by better growth parameters, which also corroborated with gibberellic acid accumulation in a dose-dependent manner. The differential activity of green synthesized IONPs, highlighted in this study, compared to already reported chemically synthesized IONPs, reveals their functional superiority.