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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. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

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

Gibberellins (GA) and paclobutrazol (PBZ) are plant growth regulators. GA promotes plant growth and development while PBZ retards plant growth. Little is known about their effects on chlorophyll synthesis and photosynthesis in young oil palm plantlets. In this study, ten-month old young clonal palms were treated with 0.02 g/palm either gibberellic acid (GA3) or PBZ. The PBZ-treated palms were shorter with compact crown, shorter fronds and leaflets, more fronds and higher Soil Plant Analysis Development (SPAD) units, particularly at time point T1. Thus, PBZ suppressed elongation in leaflets, rachis and trunk but increased fronds production and leaf chlorophyll content. Contrastingly, GA3 promoted oil palm height with significant inter-leaflet elongation and lower frond production. Chlorophyll content was also adversely affected in GA3-treated palms at time point T1. Transcriptome sequencing revealed that differentially expressed genes (DEGs) were enriched for metabolic related activities. These genes were mostly downregulated by GA3 treatment. The GA3 treatment also reduced expression of chlorophyll synthesis genes, DEGs encoding components of the photosystems I (PSI) and II (PSII) supercomplexes, cytochrome b6f, Adenosine tri-phosphate (ATP) synthase and Rubisco as well as their assembly factors, translocons and photoreceptors. Meanwhile, PBZ treatment increased expression of geranylgeranyl diphosphate reductase that may inhibit GA biosynthesis but increase chlorophyll synthesis, which was likely correlated to increased chlorophyll content in the darker green leaves of PBZ-treated palms. [ABSTRACT FROM AUTHOR]

Gibberellin, as one of the pivotal plant growth regulators, can improve fruit quality by altering fruit size and secondary metabolite content. Flavonoids are the most abundant secondary metabolites in grapes, which influence the color and quality of the fruit. However, the molecular mechanism of whether and how GA3 affects flavonoid metabolism has not been reported, especially for the 'Red globe' grape with delayed cultivation in Hexi corridor. In the present study, the 'Red globe' grape grown in delayed facilities was sprayed with 20, 40, 60, 80 and 100 mg/L GA3 at berries pea size (BPS), veraison (V) and berries ripe (BR), respectively. The results showed that the berry weight, soluble sugar content and secondary metabolite content (the flavonoid content, anthocyanin content and polyphenol content) at BR under 80 mg/L GA3 treatment were remarkably increased compared with other concentration treatments. Therefore, RNA sequencing (RNA-seq) was used to analyze the differentially expressed genes (DEGS) and pathways under 80 mg/L GA3 treatment at three periods. GO analysis showed that DEGs were closely related to transporter activity, cofactor binding, photosynthetic membrane, thylakoid, ribosome biogenesis and other items. The KEGG enrichment analysis found that the DEGs were mainly involved in flavonoid biosynthesis and phenylpropanoid biosynthesis, indicating GA3 exerted an impact on the color and quality of berries through these pathways. In conclusion, GA3 significantly increased the expression of genes related to flavonoid synthesis, enhanced the production of secondary metabolites, and improved fruit quality. In addition, these findings can provide a theoretical basis for GA3 to modulate the accumulation and metabolism of flavonoids in grape fruit. [ABSTRACT FROM AUTHOR]

Abiotic stresses including fluoride (F−) affect the quality and quantity of plant growth right from germination. The present study comparatively evaluates physiological and biochemical changes in four staple crops (Oryza sativa, Triticum aestivum, Zea mays and Pennisetum glaucum) against F− toxicity (50, 100, 150, 200 and 250 µg mL−1) during germination. Fluoride (µg g−1) accumulation in tissues of seedlings exhibited: O. sativa (8.9) > Z. mays (7.89) > P. glaucum (6.5) > T. aestivum (6.17) against 250 µg F− mL−1, in 15d-old seedlings. T. aestivum was most sensitive among the studied crops, owing to its lowest LC50 (132 µg mL−1), F−accumulation, correspondingly highest reduction in phytohormone (gibberellic acid, 32.6%), glycolytic enzyme (enolase, 46.38%), starch hydrolysis enzyme (α-amylase, 40%), total chlorophyll (7.81%) and fresh weight (20.83%) against 50 µg F− mL−1. Contrarily, P. glaucum had the highest LC50 (188 µg mL−1) and the highest Km value (167.2), exhibiting tolerance towards F−. Enhancement in the expression of oxidative stress markers and antioxidant enzyme activity were in the order: O. sativa > T. aestivum > Z. mays > P. glaucum. Further, F− stress also distorted the stomatal shape and reduced the number and diameter of metaxylem in all the F−-treated seedlings, against all F−concentrations. [ABSTRACT FROM AUTHOR]

Plant-specific GRAS transcription factors (TFs) are reported to play an essential role in regulating several biological processes, such as plant growth and development, phytochrome signal, arbuscular mycorrhiza symbiosis, stress responses. However, rose GRAS genes are still unexplored. In this study, 59 rose GRAS genes (RcGRAS) were identified and were grouped into 17 subfamilies. Gene structure analyses showed that most of the RcGRAS genes were intronless and were relatively conserved. Gene expression analysis in various tissues (leaf, stem and flower bud) identified the tissue-specific expression of GRAS genes. For instance, RcGRAS30 (SCL3) and RcGRAS9 (HAM) got > 20 fold and > 5 folds upregulated in stem as comparison to leaf, and suggested their possible involvement in different growth and development processes. Further, significant difference in expression of GRAS genes in response to exogenous gibberellin (GA) and drought stress alluded the potential functions of these genes in hormone and stress responses. In summary, a comprehensive exploration of the rose GRAS gene family was performed and also their possible role in growth, development, stress and hormonal response were depicted. These basic insights can be utilized for further functional characterization-based studies on GRAS genes. [ABSTRACT FROM AUTHOR]

The use of plant growth regulators has led to environmental contamination of water bodies that occur adjacent to agricultural areas. Some of these chemicals are bioactive, not only to plants, but also to non-target exposed biota, namely of the aquatic compartment. Previous work demonstrated the establishment of hepato- and nephrotoxic effects in juvenile tilapia (Oreochromis niloticus) exposed via aquatic media to gibberellic acid (GA3), which is among the most used plant growth regulators, in agricultural practices. Here, we investigated the effect of GA3 on hematological indices, poikilocytosis, nuclear abnormalities, and genotoxic indices measured in Nile tilapia (Oreochromis niloticus), as well as the putative protective effects of dietary supplementation of Spirulina (Arthrospira platensis). Fish were evenly assorted into 5 groups: group I served as a control, and groups II–V were fed diets supplemented with Spirulina at rates of 0 g/kg, 5 g/kg, 20 g/kg, and 100 g/kg, respectively, for 2 months before being exposed to 150 mg/L GA3. The results revealed that GA3 exposure decreased significantly all hematological indices (P < 0.05), except leucocytes and mean corpuscular hemoglobin concentration (MCHC), compared to the control group (P > 0.05). GA3 exposure increased significantly the percentage of nuclear abnormalities, altered erythrocytes and the percentages of tail DNA, compared to the control group (P < 0.05). Spirulina supplementation restored the hematological, poikilocytosis, nuclear abnormalities, and the percentages of tail DNA to near normal levels. The 100 g/kg SP treatment was the most effective in attaining such effect, showing concentration-dependency. The present study reinforces our findings of the toxicity of GA3 on O. niloticus and suggests that the addition of Spirulina to fish diet can mitigate the hemotoxic effects of GA3. [ABSTRACT FROM AUTHOR]

Silicon (Si) and Plant growth regulators (PGR's) are known to induce resistance against various insect pests. A study was conducted to determine the effect of Si and PGR's on biology and induced resistance in maize against recently invaded fall armyworm (FAW), Spodoptera frugiperda. Different foliar silicic acid (FSA), gibberellic acid (GA3) and jasmonic acid (JA) at different concentrations and combinations were evaluated. The larvae fed on plants treated with FSA, FSA + GA3 and jasmonic acid exhibited lower larval, pre-pupal and pupal weight, whereas no effect of gibberellic acid alone on these parameters. Application of FSA at 2 ml L−1and GA3 0.5 mg plant−1 significantly decreased the larval weight (18.38 mg at 5th day, 219.35 mg at 10th day), pre-pupal weight (168.64 mg), pupal weight (158.22 mg) and larval survival (70.00%), fecundity (500.20 eggs/female) and fertility (62.68%). Male longevity was decreased by all the treatments except with the application of GA3 and JA and female longevity was unaffected by JA. The biological parameters of S. frugiperda were negatively correlated with increase in Si, phenols and tannins and potassium concentration in leaves. The study conclusively demonstrated significant negative effect on various biological parameters of FAW when plants were treated with Si and PGR's. [ABSTRACT FROM AUTHOR]

Astragalus brachypterus Fischer (milkvetch) is a perennial medicinal plant in the family Fabaceae. Astragalus species have been utilized as antiviral, antibacterial, antifungal, antioxidant, anticancer, hepatoprotective, wound healing, anti-diabetic, and diuretic for centuries in folk medicine. Objectives of this study were to determine an in vitro regeneration system for A. brachypterus and then to compare phenolic constituents of in vitro-raised and naturally raised leaves. Various plant explants (leaf, petiole, stem, and node) were taken from sterile seedlings that were obtained from germinated seeds. The explants were transferred to Murashige and Skoog (MS) medium supplemented with different cytokinins (benzyladenine (BA), kinetin (KIN), and thidiazuron (TDZ)), auxins (indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxy acetic acid (2,4-D)), and gibberellic acid (GA3) at various concentrations. Regeneration was obtained only with explants containing preexisting meristem (node). The highest mean number (29.16 ± 4.91) and frequency of shoot proliferation (100%) were obtained with nodal explants on MS medium containing 3.0 mg L−1 BA, 1.0 mg L−1 IAA, and 0.5 mg L−1 GA3 (P ≤ 0.05). Regenerated shoots were transferred to rooting medium and root formation was only observed with 1.0 mg L−1 IAA after 6 wk. At the second stage of the study, methanolic extracts of in vitro-raised and field-raised leaves of A. brachypterus were analyzed by using liquid chromatography-electrospray ionization multistage tandem mass spectrometry (LC-ESI-MS/MS). Although naturally raised leaves contained higher amount of caffeic acid, chlorogenic acid, gallic acid, isorhamnetin, myricetin, quercetin, rutin hydrate, and vanillic acid, in vitro-raised leaves had higher amount of luteolin and apigenin. It was observed that A. brachypterus leaves were remarkable source of rutin hydrate. This study provides highly efficient method for the conservation of germplasm and mass multiplication of A. brachypterus, and helps to reveal the quality of in vitro-grown plants in terms of phenolic content production for biotechnological and commercial purposes. [ABSTRACT FROM AUTHOR]

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Soil pollution due to potentially toxic elements is a worldwide challenge for health and food security. Chelate-assisted phytoextraction along with the application of plant growth regulators (PGRs) could increase the phytoremediation efficiency of metal-contaminated soils. The present study was conducted to investigate the effect of different PGRs [Gibberellic acid (GA3) and indole acetic acid (IAA)] and synthetic chelator (EDTA) on growth parameters and Cd phytoextraction potential of Dysphania ambrosioides (L.) Mosyakin & Clemants grown under Cd-spiked soil. GA3 (10−7 M) and IAA (10−5 M) were applied four times with an interval of 10 days through a foliar spray, while EDTA (40 mg kg−1 soil) was once added to the soil. The results showed that Cd stress significantly decreased fresh biomass, dry biomass, total water contents, and photosynthetic pigments as compared to control. Application of PGRs significantly enhanced plant growth and Cd phytoextraction. The combined application of GA3 and IAA with EDTA significantly increased Cd accumulation (6.72 mg pot−1 dry biomass) and bioconcentration factor (15.21) as compared to C1 (Cd only). The same treatment significantly increased chlorophyll, proline, phenolic contents, and antioxidant activities (CAT, SOD, and POD) while MDA contents were reduced. In roots, Cd accumulation showed a statistically significant and positive correlation with proline, phenolics, fresh biomass, and dry biomass. Similarly, Cd accumulation showed a positive correlation with antioxidant enzyme activities in leaves. D. ambrosioides showed hyperaccumulation potential for Cd, based on bioconcentration factor (BCF) > 1. In conclusion, exogenous application of GA3 and IAA reduces Cd stress while EDTA application enhances Cd phytoextraction and ultimately the phytoremediation potential of D. ambrosioides. [ABSTRACT FROM AUTHOR]

Indole-3-acetic acid (IAA) and gibberellic acid (GA3) are essential for the growth and development of plants. In the present study, the ameliorative potential of these phytohormones on growth, protein content, and antioxidant enzymes was investigated in in vitro-grown Solanum tuberosum L. cultivars 'Cardinal' and 'Desiree' under salt stress. A 4 × 3 factorial combination of 0, 40, 60, or 80 mM NaCl with 0, 7, or 14 μM IAA, or 0, 14, or 21 μM GA3, were added to Murashige and Skoog (MS) basal medium, followed by inoculation of nodal explants or callus cultures. The data for root and shoot number and length, number of nodes and leaves, fresh weight of plants, increase or decrease in fresh weight of callus cultures, total soluble protein, and superoxide dismutase (SOD) and peroxidase (POD) activities were recorded after 30 d. The growth of both callus cultures and nodal explants subjected to NaCl stress was substantially reduced compared with the control. Both IAA and GA3 successfully alleviated the harmful effects of salt stress on all of the growth parameters studied. Salt stress resulted in decreased protein content, which increased when the media also contained phytohormones. The activities of SOD and POD were increased with either IAA or GA3 under NaCl stress. Therefore, the exogenous application of both IAA and GA3 not only played a positive role in terms of in vitro potato growth but also significantly affected the biochemical parameters tested. [ABSTRACT FROM AUTHOR]

Background: Globe artichoke Cynara scolymus L. is an important vegetable crop. Poor crop stand due to the low ratio of stumps surviving is the common problem which occurs with using vegetative parts. The current study evaluated two seed-propagated cultivars of artichoke: treated by GA3 and melatonin applications in newly reclaimed land. Results: Results showed that Imperial Star produced higher values of vegetative growth, yield productivity, and chemical contents, compared with Romanesco cultivar. GA3 foliar application treatment ranked the first to increase vegetative growth, yield productivity, and chemical contents, followed by melatonin treatment, compared with untreated control. Conclusion: It could be concluded that the use of GA3 and melatonin were favorable for the production of both artichoke cultivars: Imperial Star and Romanesco. The highest productivity was achieved by foliar application of GA3 to Imperial Star cultivar. [ABSTRACT FROM AUTHOR]

The induction of chilling tolerance and defense response by glycogen synthase kinase-3 (GSK-3) under gibberellic acid (GA3) treatment in peach fruit was explored at 4 °C up to 28 days. The fruits were treated with exogenous GA3 and bikinin (GSK-3 inhibitor). Results showed that exogenous GA3 alleviated chilling injury, and upregulated endogenous GA3 content in peach fruit. Furthermore, GSK-3 expression was activated by exogenous GA3 treatment. GA3 also upregulated gene expression of superoxide dismutase, peroxidase, catalase, glutathione reductase, glutathione S-transferase, and ascorbate peroxidase. Additionally, GA3 enhanced gene and protein expression of small ubiquitin-like modifier and gene expression of methionine sulfoxide reductase, and weakened gene expression of lipoxygenase and phospholipase D. These above impacts stimulated by exogenous GA3 were blocked by the addition of bikinin. Overall, GSK-3 was involved in stimulation of chilling tolerance and defense response under GA3 treatment in postharvest peach fruit. [ABSTRACT FROM AUTHOR]

The aim of this paper was to determine the changes in some biochemical and physiological processes, which occurred in seeds and seedlings of faba bean and to evaluate the germination dynamics and plant emergence after pre-sowing seeds treatment with a magnetic field. The study was carried out on Petri dishes in climatic chambers of the company HERAEUS (Germany). Each plate was lined with filter paper and 80 seeds of faba bean were sown. The paper was sprayed with the same amount of distilled water in each plate. Treatment of seeds significantly increased the activity of amylolytic enzymes in faba bean seeds and seedlings. The greatest differentiation in enzymatic activity between stimulated and nontreated seeds was noted after 96 h from the time of sowing. Seeds treated with the magnetic field showed greater dynamics of weight at the time of imbibition than nontreated seeds. Treating of seeds with a magnetic field considerably increased the amount of indole-3-acetic acid and gibberellic acid in germinating seeds, above-ground parts and in roots of faba bean seedlings. The pre-sowing treatment with a magnetic field had favorable effects on the growth and development of seedlings. [ABSTRACT FROM AUTHOR]

Cicuta virosa L. has significant medicinal, ecological, and research potential, however there is little research history about seed dormancy. We characterized morphological changes during the embryo maturation stages of C. virosa L. seeds to better understand its dormancy type and germination characteristics, which is necessary for optimizing seed propagation. In addition, water absorption measurements, germination tests, cold moist stratification, and GA3 or kinetin were used to determine dormancy and germination characteristics. C. virosa seed dormancy presents a morphophysiological dormancy (MPD) with an undeveloped embryo. Since cold moist stratification at 4 °C caused the embryo to develop and the radicle to break through seed coat, its dormancy was determined to be of a non-deep complex type. For dormancy-broken seeds, the optimal germination condition was incubation at 25 °C in the light, with a pretreatment of GA3 and kinetin. Indeed, GA3 improved the germination rate up to 90% regardless of its concentration, and kinetin at least doubled the germination rate of C. virosa seeds compared to that of the controls. Additionally, KNO3 improved germination rates by 50% with respect to that of the controls regardless of the concentration at which it was added. Our results indicate that C. virosa seeds have MPD and can be planted consistently en masse with cold stratification, GA3, kinetin, and KNO3 treatments. In particular, once the embryo has developed sufficiently, a combined administration of 500 mg L−1 GA3 and 20 mg L−1 kinetin was much more effective than either treatment alone; therefore, an appropriate method must be used based on the stage of embryo development. [ABSTRACT FROM AUTHOR]

Phenolic compounds were extracted from seeds of eight varieties i.e. Rising Sun, SMH-0907, Ausigold-7, SMH-0939, US-444, Hysun-33, SMH-0917 and HS-K6 of sunflower and characterized by HPLC-DAD method. Quantification of individual compounds was carried out by external calibration. Total of 15 phenolic compound were identified, namely hydroxybenzoic acid, hydroxybenzoyl glucose, caftaric acid, rosmanol, gallic acid derivative, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, caffeic acid, pro-anthocynidin B1, rosmannic acid, sinapic acid derivative, caffeic acid derivative 1, caffeic acid derivative 2, caffeoylmalic acid derivative and quercetin derivative in the seeds of sunflower. Different treatments of potassium nitrate, zinc sulphate, and gibberellic acid showed significant effect on the biosynthesis of phenolic compound as compared to control plants. Among the 15 compounds analyzed 3,4-di-O-caffeoylquinic acid was predominant compound in the seeds. The current results demonstrate that this method can be efficiently used for the identification and quantification of phenolic compound in sunflower seeds. [ABSTRACT FROM AUTHOR]

Growth-regulating factor (GRF) is an important protein in GA-mediated response, with key roles in plant growth and development. However, it is not known whether or how the GRF proteins in citrus to regulate organ size. In this study, nine citrus GRF genes ( CsGRF1-9) were validated from the 'Anliu' sweet orange (AL, Citrus sinensis cv. Anliu) by PCR amplification. They all contain two conserved motifs (QLQ and WRC) and have 3-4 exons. The transcript levels of genes were detected by qRT-PCR. Transcript analysis showed that (1) CsGRF 1, 2, 5, 6, 7, and 9 expressed predominantly in young leaf, CsGRF 3 and 4 expressed predominantly in fruit immature juice sacs and CsGRF 8 expressed predominantly in root; (2) all citrus GRF genes had significantly higher expression in young leaves than mature leaf; (3) in juice sacs, the transcript levels of CsGRF1, 4, 5, 6, and 8 increased significantly while the transcript levels of CsGRF2, 3, 7, and 9 had no significant change from 80 DAF to 100 DAF. Besides, GA3 treatment did not affect the transcript levels of CsGRF5 and CsGRF6 but significantly increased the transcript levels of the other seven CsGRF genes in young leaves. These results suggested that all CsGRF genes involve in the leaf development, CsGRF1, 4, 5, 6, and 8 act developmentally whilst CsGRF2, 3, 7, and 9 play fundamental roles in fruit cell enlargement, which may be through GA pathway or GA-independent pathway. [ABSTRACT FROM AUTHOR]

emisinin is a promising and potent antimalarial drug naturally produced by the plant Artemisia annua L. but in very low yield. Its artemisinin content is known to be greatly affected by both genotype and environmental factors. In this study, the production of artemisinin and leaf biomass in Artemisia annua L. was significantly increased by exogenous GA treatment. The effect of GA application on expression of proposed key enzymes involved in artemisinin yield was examined in both wild type (007) and FPS-overexpression (253-2) lines of A. annua. In the wild type (007) at 6 h post GA application there was an abrupt rise in FPS, ADS and CYP71AV1 expression and at 24 h a temporary and significant peak in artemisinin (1.45-fold higher than the control). After GA application in line 253-2, there was a dramatic rise in expression of FPS at 3 h, CYP71AV1 at 9 h and ADS at 72 h and accumulation of artemisinin after 7 days, which was a delay when compared with the wild type plant. Thus, increased artemisinin content from exogenous GA treatment was associated with increased expression of key enzymes in the artemisinin biosynthesis pathway. Interestingly, exogenous GA continuously enhanced artemisinin content from the vegetative stage to flower initiation in both plant lines and gave significantly higher leaf biomass than in control plants. Consequently, the artemisinin yield in GA-treated plants was much higher than in control plants. Although the maximum artemisinin content was found at the full blooming stage [2.1% dry weight (DW) in 007 and 2.4% DW in 253-2], the highest artemisinin yield in GA-treated plants was obtained during the flower initiation stage (2.4 mg/plant in 007 and 2.3 mg/plant in 235-2). This was 26.3 and 27.8% higher, respectively, than in non-treated plants 007 and 253-2. This study showed that exogenous GA treatment enhanced artemisinin production in pot experiments and should be suitable for field application. [ABSTRACT FROM AUTHOR]

The temporal and spatial changes in reactive oxygen species (ROS) during dark treatment of Pelargonium cuttings and the effect of gibberellic acid (GA3) on ROS levels were studied. ROS-related fluorescence was detected in mitochondria and cytoplasm of epidermal cells and in chloroplasts. By monitoring dichlorofluorescein (DCF) fluorescence, an initial decrease in ROS was observed under darkness in the epidermal cell cytoplasm and the chloroplasts, which was followed by an increase on the third day. Following 3 days under darkness, the size and the structure of the chloroplasts also changed, and they became more sensitive to illumination as judged by a higher accumulation of ROS. Pretreatment of leaves with GA3 did not prevent the structural changes in the chloroplasts, but it inhibited the increase in ROS levels in all cell compartments, including the chloroplasts. It is suggested that the inhibition of ROS increase by GA3 prevented complete disintegration of chloroplasts during dark-induced senescence and thereby enabled the maintenance of chlorophyll levels in the tissue. [ABSTRACT FROM AUTHOR]

After subjecting the seeds to GA3, and H2O2 treatments for 24 h and chilling at 2–3°C for a period of 15 days, we conducted the seed germination tests for 21 different seed sources of Pinus roxburghii from western-central Himalaya under laboratory conditions at various temperatures viz., 20°C, 25°C and 30°C inside a seed germinator. The results reveal that the soaking of seeds in H2O2 (1% v/v) and GA3 (10 mg·L−1) solutions manifested 82.39% and 78.19% germination, respectively whereas untreated seeds exhibited 70.79% average germination. Both GA3 and H2O2 treatments caused an appreciable shortening of the germination period by 8 days and 10 days, respectively. Moist-chilling did improve the rate and percentage of germination when germinated at 20°C over 21 days; however total germination was not affected at temperatures 25°C and 30°C. Although the seeds of P. roxburghii germinate well due to lack of dormancy, the increasing demand for large quantities of seeds of P. roxburghii for reforestation programmes make pre-sowing treatments useful in improving the rate and percentage of germination. [ABSTRACT FROM AUTHOR]

Seedlings of Amaranthus caudatus grown under UV exclusion filters (-UV -B <320nm; -UV -B/A <400nm) in the ambient solar radiation showed an enhancement in growth. This was accompanied by reduction in the synthesis of betacyanin but enhancement in the level of amino acids and proteins. The growth promotion and the accompanying biochemical changes were similar to the external application of GA3 to the seedlings under ambient solar radiation. The results are discussed in the light of similarities between UV exclusion and GA3 application in terms of diversion of amino acid precursors towards enhanced primary metabolism. [ABSTRACT FROM AUTHOR]

AbstractAim:Gambogic acid (GA) is the major active ingredient of gamboge, which is secreted from a Chinese traditional medicine, Garcinia hanburyi, which possesses potent antitumor activity. GA3, a new GA derivative, has been shown to possess better water solubility than GA. The aim of the present study was to examine the antitumor activity of GA3 and the mechanism underlying it.Methods:The growth inhibition of cancer cell lines induced by GA3 was assessed using the SRB assay. DAPI staining, flow cytometry, a DNA fragment assay, and Western blot analysis were used to study the apoptotic mechanisms of GA3.Results:GA3 displayed wide cytotoxicity in diversified human cancer cell lines with a mean IC50 value of 2.15 μmol/L. GA3 was also effective against multidrug resistant cells, with an average resistance factor (RF) that was much lower than that of the reference drug, doxorubicin. Mechanistic studies revealed that GA3-induced apoptosis in HL-60 cells proceeded via both extrinsic and intrinsic pathways, with caspase-8 functioning upstream of caspase-9. In addition, GA3-driven apoptotic events were associated with up-regulation of Bax, down-regulation of Bcl-2 and cleavage of Bid. Moreover, GA3 triggered cytochrome c release from the mitochondria, in particular bypassing the involvement of the mitochondrial membrane potential.Conclusion:Better solubility and a potential anti-MDR activity, combined with a comparable antitumor efficacy, make GA3 a potential drug candidate in cancer therapy that deserves further investigation.Acta Pharmacologica Sinica (2009) 30: 346–354; doi: 10.1038/aps.2009.3 [ABSTRACT FROM AUTHOR]

The role of endogenous GA3 and its application to seed development in two cotton genotypes Hybrid-6 (H-6) (big seeds) and Gujarat cotton 13 (G. Cot) (small seeds) was studied. Kernel and seed coat were subjected to growth analysis in terms of dry weight, water amount, and rates of dry matter accumulation and water uptake. H-6 kernel had manifold higher dry weight and water amount than G. Cot. Seed coat of both genotypes had similar dry weight at maturity, but the maximum rates of dry matter accumulation and water uptake were distinctly higher in H-6. According to growth analysis, development of seed kernel and coat was subdivided into four phases, i.e., cell division, cell elongation, dry matter accumulation and maturation. Endogenous GA3 level was estimated in kernel and seed coat by indirect ELISA using antibodies raised against GA3. GA3 amount per seed components was higher in the seed kernel of H-6 than of G. Cot, except 33 and 36 days after anthesis in kernel. H-6 seed coat had the higher amount of GA3 during cell division phase than that of G. Cot. Close correlation between in vivo GA3 level and water amount was recorded in both seed components. With GA3 or GA3 + NAA treatments in ovule culture, higher promotion in dry weight, water amount and seed size was noted in G. Cot than in H-6 suggesting that G. Cot is more deficient in endogenous GA3. The greatest stimulation of parameters studied was obtained in ovule culture with GA3 + NAA. When GA3 or GA3 + NAA was applied, initial significant difference in water amount and seed size was nullified. Data presented in this study indicated that GA3 regulates cell expansion through the water uptake by cotton seed. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effect of GA3, moist-chilling and temperature on seed germination of Abies pindrow and Picea smithiana from five different provenances. Seeds were soaked in GA3 (10 mg·L−1) for 24 h, then chilled at 3–5°C for 15 days. Four temperature regimes viz. 10°C, 15°C, 20°C and 25°C were used for stimulating seed germination. Results showed that soaking and chilling significantly increased germination percentage. The germination percentage was highest at 10°C. Overall results showed that soaking seeds in GA3 (10 mg·L−1) for 24 h, moist chilling for 15 days, and germinating at 10°C produced an effective germination in both the species studied. The statistical analysis of the data proclaimed significant effect of treatment, temperature, provenance and treatment with temperature interactions on seed germination. [ABSTRACT FROM AUTHOR]

Investigations on seeds of Scrophularia marilandica L. were undertaken to determine their germination requirements. Seeds were collected from three naturally occurring sites and one greenhouse-grown population in London, Ontario in September and October of 1997. Some were set to germinate immediately after collection; others were stored in or on soil outside and/or under controlled laboratory conditions before testing. Germination was assessed under two light/temperature regimes (35°C 14 h light, 20°C 10 h dark and 25°C 14 h light, 10°C 10 h dark), in continuous darkness, and in the presence of two germination-promoting chemicals (GA3 and KNO3). Fresh seeds germinated best at 35/20°C, while stored seeds germinated best at 25/10°C. No differences in percent germination were found among three seed-maturity stages. All chemical treatments, except 0.01 M KNO3, increased percent germination. Significant differences were found both among and within sites for most chemical treatments, but exposure to 3 × 10−4 M GA3 caused almost every seed to germinate. When compared to the control, both the gibberellic acid and the soil-storage treatments contributed to faster germination. Exposure of seeds to naturally prevailing conditions on the soil surface followed by testing under the 25/10°C regime produced the highest percent germination. No seeds germinated in the dark. In summary, seeds of S. marilandica exhibit physiological dormancy, which can be alleviated by exposure to light, after-ripening and/or cold stratification. It is probable that the differences in germination response among sites can be attributed to differences in environmental conditions during seed production. These experiments indicate that the seeds of S. marilandica must be buried shortly after dispersal in order to form a persistent seed bank. [ABSTRACT FROM AUTHOR]

Changes in genomic nucleic acid content and salt induced alteration in polypeptide pattern were studied in two resistant (C 92038 & Co 85004) and two susceptible (Co 85036 & Si 94050) sugarcane genotypes under salt stress (7 EC). Result of the study revealed that changes in RNA and DNA content under salinity stress might be responsible for specific expression of salt shock proteins (SSP) with MW of 15 kDa, 28 kDa and 72 kDa in tolerant genotypes, while there were completely absent in susceptible. However, supplementing GA3 under salt stress condition enhanced nucleic acid content (RNA) and thus induced expression of SSP in susceptible genotypes with low intensity. [ABSTRACT FROM AUTHOR]

Laurel (Laurus nobilis L.) seeds were collected from the west part of Turkey in the fall of 2002. Seeds with pericarp (+) or without pericarp ( ) were treated with 1000 mg/l, 2000 mg/l and 3000 mg/lGA3 concentrations, cold stratified at + 4 ± 1°C for 25 and 50 days, punctured and seed coat removed to overcome and assess the mechanism of laurel seed dormancy. A period of 50 days cold stratification and removing seed coat significantly increased germination rate to 55% ± 1.91 (Mean ± SE) and 85% ± 3.00, respectively. None of the seeds with pericarp germinated regardless of treatment they underwent. Results suggested that seed dormancy was mainly due to pericarp and perhaps inhibitors linked to seed coat. [ABSTRACT FROM AUTHOR]

Seedling survival and growth of two common Vallisneria species in China, Vallisneria natans and Vallisneria spinulosa were quantified experimentally for current velocities from 0 to 40 mm/s. At the same time, changes in the concentrations of three hormones (IAA, ZR, and GA3) in the leaves were compared to identify how current velocity influenced the two Vallisneria seedlings growth discrepantly. All plants survived in all treatments and showed positive growth. The most rapid growth for both species was found at the velocity of 10 mm/s. Although V. spinulosa showed faster growth than V. natans at the beginning of the experiment, there was no significant difference on final biomass. Higher IAA and ZR contents were measured in seedlings of both species grown under low current velocity. The time reaching the maximum for IAA and ZR was just around the time of a maximum seedling growth rate. IAA and ZR contents were positively correlated with growth rate. However, GA3 was negatively associated with growth rate and more GA3 in V. natans seedlings was induced by high current velocity. [ABSTRACT FROM AUTHOR]

Presence of five carboxypeptidases was found in endosperm of germinating triticale grains, while two of them in scutellum. Changes of their activities during four days of germination suggest that carboxypeptidase II plays an important role at initial stage of germination, while carboxypeptidases I and III - at subsequent stages of the process. High activity of carboxypeptidase II both in scutellum and endosperm of dry grains accompanied by its decrease during germination, and on the other hand, the appearance of carboxypeptidases I and III activities at the 2nd and 3rd day of the process seems to confirm such functions of these enzymes. Experiments with GA3 indicated that carboxypeptidase I was synthesized in scutellum, and carboxypeptidase III — in aleurone layer. Carboxypeptidases I and II cleave N-CBZ-Phe-Ala, and carboxypeptidase III — N-CBZ-Ala-Met and N-CBZ-Ala-Phe as substrates with the highest rate. [ABSTRACT FROM AUTHOR]

In flowering plants, anthers bear male gametophytes whose development is regulated by the elaborate coordination of many genes. In addition, both gibberellic acid (GA3) and jasmonic acid (JA) play important roles in anther development and pollen fertility. To facilitate the analysis of anther development genes and how GA3 and JA regulate anther development, we performed microarray experiments using a 10-K cDNA microarray with probes derived from seedlings, meiotic anthers, mature anthers and GA3- or JA-treated suspension cells of rice. The expression level change of 2155 genes was significantly (by 2-fold or greater) detected in anthers compared with seedlings. Forty-seven genes, representing genes with potential function in cell cycle and cell structure regulation, hormone response, photosynthesis, stress resistance and metabolism, were differentially expressed in meiotic and mature anthers. Moreover, 314 genes responded to either GA3 or JA treatment, and 24 GA3- and 82 JA-responsive genes showed significant changes in expression between meiosis and the mature anther stages. RT-PCR demonstrated that gene y656d05 was not only highly expressed in meiotic anthers but also induced by GA3. Strong RNA signals of y656d05 were detected in pollen mother cells and tapetum in in situ hybridization. Further characterization of these candidate genes can contribute to the understanding of the molecular mechanism of anther development and the involvement of JA and GA3 signals in the control of anther development in rice. [ABSTRACT FROM AUTHOR]

Results of the pot culture experiment revealed that, major and micro nutrients uptake and partitioning of the essential nutrients viz., N, P, K, Ca, Mg, Zn, Fe, Mn, were significantly affected due to salt stress, while salt induced accumulation of toxic elements viz., Na, Cl, Al, Mo, and Cu was enhanced particularly in Si 94050 and Co 85036 (susceptible genotypes). The resistant genotypes, C 92038 and Co 85004 performed better by maintaining higher N, P, K, Ca, Mg and higher K/Na ratio. Sodium induced Ca deficiency were also observed in Co 85036 under salt stress. The important quality parameters, viz., juice brix %, purity %, CCS % and sucrose % juice decreased by due to salinity, 10.60, 12.22, 23.71 and 22.82 percent, respectively. While juice Ec, pH and reducing sugar were considerably increased 38.11 due to salt stress. However, the reduction in brix %, purity %, CCS % and sucrose % as well as increase in juice pH, EC and reducing sugar were less in C 92038 and Co 85004, while it was viceversa for susceptible genotypes, which lead to poor economic yield. Irrespective of the genotypes, supplementing GA3 (150 ppm) as sett treatment and foliar application play role on imparting salt tolerance in terms of enhancing nutrient uptake as well as quality aspects. [ABSTRACT FROM AUTHOR]

The contents of artemisinin and artemisinic acid were monitored in theArtemisia annuaplants treated with GA3 at vegetative and flowering initiation stages. The highest artemisinin content was observed at full bloom. The decrease in artemisinic acid content occurred during the transition from the vegetative stage to the beginning of flowering. Endogenous GA3 content in the leaves peaked at full bloom. At the vegetative stage, in plants treated with various concentrations of GA3 , the content of artemisinin increased while that of artemisinic acid decreased. Apparently, the rate-limiting step in artemisinin biosynthesis was from artemisinic acid to artemisinin. The “bottleneck” of artemisinin biosynthesis was probably unlocked during the flowering or in the vegetative plants treated with GA3 , which triggered off the conversion of artemisinic acid to artemisinin. [ABSTRACT FROM AUTHOR]

We tested various pretreatments to enhance the germination of ‘Sea bells’ ( Calystegia soldanella Roem. et Schult). One experiment, which improved the germination rate by 70%, involved first scarifying the seed coats, then immersing the seeds in 50 ppm GA3 for 24 h. A GA3-alone pretreatment did not increase germination. However, the most effective method, with a 100% success rate, included 3 h of acid pretreatment with 98% H2SO4. We also used scanning electron microscopy (SEM) to examine the seed-coat surfaces and cross-sections of dry seeds. SEM showed structural differences between seeds that were not treated and those exposed to 98% H2SO4. The latter treatment allowed the seed coats to crack and break, thereby disrupting their physical dormancy. [ABSTRACT FROM AUTHOR]

Podophyllum hexandrum Royle, an important alpine herb, is the source of highly valued podophyllotoxin. The effect of some plant growth substances (GA3, BAP & ABA), uniconazole (an inhibitor of GA biosynthesis), and a combination of GA3 and uniconazole were examined in respect to influence on sprouting in rhizomes of P. hexandrum and on induction of flowering at a lower altitude. Amongst the various chemicals tested, GA3 had a marked effect resulting in uniform sprouting and also induced flowering in about half of the treated rhizomes. While BAP also promoted early sprouting, delayed sprouting was seen in rhizomes treated with ABA. Uniconazole treatment, either alone or with GA3 was found to inhibit flowering and also resulted in reduced plant height. GA3 treatment of rhizomes from plants that was maintained for up to 30 months at a lower altitude also induced flowering thus replacing the normal chilling requirement of plants. These results suggest that treatment of GA3 could be effectively used for inducing uniform sprouting and flowering in rhizomes of P. hexandrum grown at lower altitudes. [ABSTRACT FROM AUTHOR]

We studied the effect of exogenous applications of GAon3 on rubisco activation in soybean leaves. Activity at 0.1 μM GA3 was significantly greater than in leaves receiving no treatment Rubisco content snowed patterns of change similar to that for activity. These data suggest that activity was associated with the amount of rubisco protein, and that the activation and induction of rubisco was promoted by GA3. The degree of intensity of the 50 and 14.5-kD polypeptides (identified as the large and small subunit, respectively, of rubisco by SDS-PAGE analysis) at 0.1 μM GA3 was significantly higher than that for the control, indicating that GA3 affected both subunits. The stimulation effects of rubisco activation by GA3 seem to be caused by the expression of rubisco genes at the transcriptional level. Assuming that these GA3 effects were related to rubisco activase, we also determined the activity and content of that enzyme. Its activity at 0.1 μM GA3 increased more than did the control. A similar pattern of change was observed for rubisco activase content The intensity of two 46- and 42-kD polypeptide bands at GA3 was higher than for the corresponding bands at the control. Therefore, the change in rubisco activase levels may lead to altered levels of rubisco. [ABSTRACT FROM AUTHOR]

The flavonoid 3′,5′-hydroxylase (F3′,5′H) gene is in the NADPH-Cytochrome P450 reductase family. A partial F3′,5′H cDNA was cloned by RT-PCR from corollas of Gentiana scabra. Activity of F3′,5′H was observed during flower development, and activity was highest at the stage prior to flower opening. The enzyme activity was increased with the addition of SO μM gibberellic acid (GA3) immediately prior to flower opening. Western blot analysis showed that purified F3′,5′H protein from G. scabra was cross-reacted with rabbit anti-Gentiana triflora NADPH-Cyt P450 reductase antibodies. Only one 80 to 82 kDa protein was detected by western blot analysis of fresh microsomal extracts. The enzyme activity was not distinctly changed by adding 50 μM GA3 to corollas. Therefore, we conclude that GA3 controls the expression of the F3′,5′H gene at the transcriptional level, not at the translational level. [ABSTRACT FROM AUTHOR]

Background: Two field experiments were carried out in Researches and Production Station of National Research Centre, Al-Nubaria District, Al Behaira Governorate, Egypt. To study the effect of indole acetic acid (IAA) and /or gibberellic acid (GA3) on growth, photosynthetic pigments, yield, and chemical composition of mungbean seeds, different concentrations of IAA and/or GA3 were used. Results: Results indicated that all treatments caused significant increases in morphological criteria, biochemical parameters, and yield of mungbean plants. IAA or GA3 with 50 mg/l concentration recorded the best values growth photosynthetic pigments, as well as, endogenous auxins, GA3, and cytokinins. Interaction of IAA 50 mg/l + GA3 50 mg/l gave the most effective treatment. The superiority of treatment IAA 50 mg/l, GA3 50 mg/l, and interaction of IAA 50 mg/l + GA3 50 mg/l recorded the same trend due to yield and yield components in characters' plant height, pods no./plant, pods weight/plant, seeds no./pod, seed yield, straw yield, biological yield, total carbohydrates, protein in seeds (%), and N in seeds (%). Conclusion: It could be concluded that foliar spray of 50 mg/l IAA + 50 mg/l GA3 was the most effective treatment on increasing growth and yield of mungbean. [ABSTRACT FROM AUTHOR]