Showing papers on "Gibberellic acid published in 2011"
TL;DR: It is concluded that low nitrate induces flowering via a novel signalling pathway that acts downstream of, but interacts with, the known floral induction pathways.
Abstract: The transition from vegetative growth to reproduction is a major developmental event in plants. To maximise reproductive success, its timing is determined by complex interactions between environmental cues like the photoperiod, temperature and nutrient availability and internal genetic programs. While the photoperiod- and temperature- and gibberellic acid-signalling pathways have been subjected to extensive analysis, little is known about how nutrients regulate floral induction. This is partly because nutrient supply also has large effects on vegetative growth, making it difficult to distinguish primary and secondary influences on flowering. A growth system using glutamine supplementation was established to allow nitrate to be varied without a large effect on amino acid and protein levels, or the rate of growth. Under nitrate-limiting conditions, flowering was more rapid in neutral (12/12) or short (8/16) day conditions in C24, Col-0 and Laer. Low nitrate still accelerated flowering in late-flowering mutants impaired in the photoperiod, temperature, gibberellic acid and autonomous flowering pathways, in the fca co-2 ga1-3 triple mutant and in the ft-7 soc1-1 double mutant, showing that nitrate acts downstream of other known floral induction pathways. Several other abiotic stresses did not trigger flowering in fca co-2 ga1-3, suggesting that nitrate is not acting via general stress pathways. Low nitrate did not further accelerate flowering in long days (16/8) or in 35S::CO lines, and did override the late-flowering phenotype of 35S::FLC lines. We conclude that low nitrate induces flowering via a novel signalling pathway that acts downstream of, but interacts with, the known floral induction pathways.
159 citations
TL;DR: It is demonstrated that auxin is linked via the IAA30 gene with a salt signaling cascade mediated by the NAM-ATAF1/2-CUC2 transcription factor NTM2/Arabidopsis NAC domain-containing protein 69 during seed germination.
Abstract: Seed germination is regulated through elaborately interacting signaling networks that integrate diverse environmental cues into hormonal signaling pathways. Roles of gibberellic acid and abscisic acid in germination have been studied extensively using Arabidopsis (Arabidopsis thaliana) mutants having alterations in seed germination. Auxin has also been implicated in seed germination. However, how auxin influences germination is largely unknown. Here, we demonstrate that auxin is linked via the IAA30 gene with a salt signaling cascade mediated by the NAM-ATAF1/2-CUC2 transcription factor NTM2/Arabidopsis NAC domain-containing protein 69 (for NAC with Transmembrane Motif1) during seed germination. Germination of the NTM2-deficient ntm2-1 mutant seeds exhibited enhanced resistance to high salinity. However, the salt resistance disappeared in the ntm2-1 mutant overexpressing the IAA30 gene, which was induced by salt in a NTM2-dependent manner. Auxin exhibited no discernible effects on germination under normal growth conditions. Under high salinity, however, whereas exogenous application of auxin further suppressed the germination of control seeds, the auxin effects were reduced in the ntm2-1 mutant. Consistent with the inhibitory effects of auxin on germination, germination of YUCCA 3-overexpressing plants containing elevated levels of active auxin was more severely influenced by salt. These observations indicate that auxin delays seed germination under high salinity through cross talk with the NTM2-mediated salt signaling in Arabidopsis.
156 citations
TL;DR: In this paper, the authors established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of phytohormones cytokinins (CK) and gibberellins (GA) and showed that application of GA(3) is sufficient to induce sprouting.
Abstract: Reactivation of dormant meristems is of central importance for plant fitness and survival. Due to their large meristem size, potato (Solanum tuberosum) tubers serve as a model system to study the underlying molecular processes. The phytohormones cytokinins (CK) and gibberellins (GA) play important roles in releasing potato tuber dormancy and promoting sprouting, but their mode of action in these processes is still obscure. Here, we established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK and show that application of gibberellic acid (GA(3)) is sufficient to induce sprouting. In contrast, treatment with 6-benzylaminopurine induced bud break but did not support further sprout growth unless GA(3) was administered additionally. Transgenic potato plants expressing Arabidopsis (Arabidopsis thaliana) GA 20-oxidase or GA 2-oxidase to modify endogenous GA levels showed the expected phenotypical changes as well as slight effects on tuber sprouting. The isopentenyltransferase (IPT) from Agrobacterium tumefaciens and the Arabidopsis cytokinin oxidase/dehydrogenase1 (CKX) were exploited to modify the amounts of CK in transgenic potato plants. IPT expression promoted earlier sprouting in vitro. Strikingly, CKX-expressing tubers exhibited a prolonged dormancy period and did not respond to GA(3). This supports an essential role of CK in terminating tuber dormancy and indicates that GA is not sufficient to break dormancy in the absence of CK. GA(3)-treated wild-type and CKX-expressing tuber buds were subjected to a transcriptome analysis that revealed transcriptional changes in several functional groups, including cell wall metabolism, cell cycle, and auxin and ethylene signaling, denoting events associated with the reactivation of dormant meristems.
137 citations
01 Jan 2011
TL;DR: An in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK shows that application of gibberellic acid (GA3) is sufficient to induce sprouting and indicates that GA is not sufficient to break dormancy in the absence of CK.
Abstract: Reactivation of dormant meristems is of central importance for plant fitness and survival. Due to their large meristem size, potato (Solanum tuberosum) tubers serve as a model system to study the underlying molecular processes. The phytohormones cytokinins (CK) and gibberellins (GA) play important roles in releasing potato tuber dormancy and promoting sprouting, but their mode of action in these processes is still obscure. Here, we established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK and show that application of gibberellic acid (GA 3 ) is sufficient to induce sprouting. In contrast, treatment with 6-benzylaminopurine induced bud break but did not support further sprout growth unless GA 3 was administered additionally. Transgenic potato plants expressing Arabidopsis (Arabidopsis thaliana) GA 20-oxidase or GA 2-oxidase to modify endogenous GA levels showed the expected phenotypical changes as well as slight effects on tuber sprouting. The isopentenyltransferase (IPT) from Agrobacterium tumefaciens and the Arabidopsis cytokinin oxidase/dehydrogenase1 (CKX) were exploited to modify the amounts of CK in transgenic potato plants. IPT expression promoted earlier sprouting in vitro. Strikingly, CKX-expressing tubers exhibited a prolonged dormancy period and did not respond to GA3. This supports an essential role of CK in terminating tuber dormancy and indicates that GA is not sufficient to break dormancy in the absence of CK. GA3-treated wild-type and CKX-expressing tuber buds were subjected to a transcriptome analysis that revealed transcriptional changes in several functional groups, including cell wall metabolism, cell cycle, and auxin and ethylene signaling, denoting events associated with the reactivation of dormant meristems.
129 citations
TL;DR: The results indicate that Glyceraldehyde 3-phosphate dehydrogenase, glutathione S-transferase (GST) 9, GST 10, and seed maturation protein PM36 might have important roles in defense mechanisms against salt stress during soybean seed germination.
Abstract: Soybean (Glycine max (L.) Merrill) is a salt-sensitive crop, and its production is severely affected by saline soils. Therefore, the response of soybean seeds to salt stress during germination was investigated at both physiological and proteomic levels. The salt-tolerant cultivar Lee68 and salt-sensitive cultivar N2899 were exposed to 100 mmol/L NaCl until radicle protrusion from the seed coat. In both cultivars, the final germination percentage was not affected by salt, but the mean germination times of Lee68 and N2899 were delayed by 0.3 and 1.0 d, respectively, compared with controls. In response to salt stress, the abscisic acid content increased, and gibberellic acid (GA1+3) and isopentenyladenosine decreased. Indole-3-acetic acid increased in Lee68, but remained unchanged in N2899. The proteins extracted from germinated seeds were separated using two-dimensional gel electrophoresis (2-DE), followed by Coomassie brilliant blue G-250 staining. About 350 protein spots from 2-DE gels of pH range 3 to 10 and 650 spots from gels of pH range 4 to 7 were reproducibly resolved, of which 18 protein spots showed changes in abundance as a result of salt stress in both cultivars. After matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis of the differentially expressed proteins, the peptide mass fingerprint was searched against the soybean UniGene database and nine proteins were successfully identified. Ferritin and 20S proteasome subunit β-6 were up-regulated in both cultivars. Glyceraldehyde 3-phosphate dehydrogenase, glutathione S-transferase (GST) 9, GST 10, and seed maturation protein PM36 were down-regulated in Lee68 by salt, but still remained at a certain level. However, these proteins were present in lower levels in control N2899 and were up-regulated under salt stress. The results indicate that these proteins might have important roles in defense mechanisms against salt stress during soybean seed germination.
74 citations
TL;DR: The determination of activities of antioxidative enzymes revealed involvement of these enzymes in callus formation and differentiation and played significant roles in the scavenging of toxic free radicals in Brassica rapa var.
Abstract: The regeneration potential and antioxidative enzyme activities of economically important Brassica rapa var. turnip were evaluated. Calli were induced from leaf explants of seed-derived plantlets on Murashige and Skoog (MS) medium incorporated with different concentrations of various plant growth regulators (PGRs). The highest leaf explant response (83%) was recorded for 2.0 mg l−1 benzyladenine (BA) and 1.0 mg l−1 α-naphthaleneacetic acid (NAA). Subsequent subculturing of callus after 3 weeks of culture, on medium with similar compositions of PGRs, induced shoot organogenesis. The highest shoot induction response (83%) was recorded for 5.0 mg l−1 BA after 5 weeks of transfer. However, 7.8 shoots/explant were recorded for 2.0 mg l−1 BA. The transferring of shoots to elongation medium resulted in 5.1-cm-long shoots on 10 mg l−1 of gibberellic acid (GA3). Rooted plantlets were obtained on MS medium containing different concentrations of indole butyric acid (IBA). The determination of activities of antioxidative enzymes (superoxide dismutase [SOD], ascorbate peroxidase [APX], catalase [CAT], glutathione peroxidase [GPX], and peroxidase [POD]) revealed involvement of these enzymes in callus formation and differentiation. All of the activities were interlinked with each other and played significant roles in the scavenging of toxic free radicals. This study will help in the advancement of a regeneration protocol for B. rapa var. turnip and the understanding of the functions of antioxidative enzymes in plant differentiation.
74 citations
TL;DR: It is found that a membrane-bound NAC transcription factor NTM2 mediates the signaling crosstalk between auxin and salt stress via the IAA30 gene during seed Germination in Arabidopsis, providing a role of auxin in modulating seed germination under high salinity.
Abstract: Seed germination is an elaborate developmental process that is regulated through intricate signaling networks integrating diverse environmental cues into endogenous hormonal signaling pathways. Accumulating evidence in recent years supports the role of auxin in seed germination. Whereas the roles of gibberellic acid (GA) and abscisic acid (ABA) in the germination process have been studied extensively, how auxin modulates seed germination is largely unknown. We found that a membrane-bound NAC transcription factor NTM2 mediates the signaling crosstalk between auxin and salt stress via the IAA30 gene during seed germination in Arabidopsis. Germination of the NTM2-deficient ntm2-1 mutant seeds exhibited enhanced resistance to high salinity. However, the salt resistance was reduced in the ntm2-1 mutant overexpressing the IAA30 gene, which was induced by high salinity in a NTM2-dependent manner. Exogenous auxin treatment further suppressed the reduced germination rate of control seeds under high salinity. In co...
72 citations
TL;DR: There is evidence that the change in phytohormone levels is one of the direct mechanism by which T22 promotes rooting and shoot growth, with notable advantages for rootstock production during nursery processes.
Abstract: The aim of this research was to explain the direct plant growth-promoting activity of Trichoderma harzianum strain T-22 (T22), hypothesizing the involvement of different classes of plant growth regulators. Seven days after the transfer to root-inducing medium, in vitro-cultured shoots of GiSeLa6® (Prunus cerasus × P. canescens) were inoculated with T22. Root and shoot growth were significantly affected by T22 (+76 and +61%, respectively). Ten days after inoculation, the levels of indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), dihydrozeatin riboside (DHZR), gibberellic acid (GA3) and abscisic acid (ABA) were analyzed by high performance liquid chromatography coupled with mass spectrometry. The results showed that after T22-inoculation, IAA and GA3 significantly increased in both leaves (+49 and +71%, respectively) and roots (+40 and +143%, respectively) whereas t-ZR decreased (−51% in leaves and −37% in roots). Changes in DHZR were observed in T22-inoculated roots (−32%) but not in leaves, whereas the levels of ABA did not differ between the two treatments. The extraction method allowed the simultaneous extraction of phytohormones. There is evidence that the change in phytohormone levels is one of the direct mechanism by which T22 promotes rooting and shoot growth, with notable advantages for rootstock production during nursery processes.
67 citations
TL;DR: Oryza sativa dwarf rice with overexpression of gibberellin-induced gene OsDOG has a novel function in regulating GA homeostasis and in negative maintenance of plant cell elongation in rice.
55 citations
TL;DR: The results imply that GsGASA1 participates in chronic cold-induced root growth inhibition with the accumulation of DELLA genes, a class of transcriptional regulators in GA signaling pathway restraining plant growth.
44 citations
TL;DR: Molecular marker Xbarc3-6A for Rht14, Rht16 and Rht18 showed significant polymorphic differences among DNA bulks for height classes and semi-dwarf genes on chromosome 6AS may potentially be used in breeding for improved establishment.
Abstract: Semi-dwarf varieties in wheat associated with gibberellic acid (GA3)-insensitive height reducing genes have led to significant increases in yield but often fall below this potential because of poor seedling emergence after deep showing. Alternative semi-dwarf genes may have the potential to reduce plant height without compromising early plant growth. In durum wheat, bulk segregant analysis was used to screen microsatellite markers linked with the GA3-sensitive genes Rht14 in cv. Castelporziano, Rht16 in cv. Edmore M1 and Rht18 in cv. Icaro. Molecular marker Xbarc3-6A for Rht14, Rht16 and Rht18 showed significant polymorphic differences among DNA bulks for height classes. The genes Rht14, Rht16 and Rht18 were linked with Xbarc3 (11.7–28.0 cM) on the short arm of chromosome 6A and they appear to be allelic. Semi-dwarf genes on chromosome 6AS may potentially be used in breeding for improved establishment.
TL;DR: In this paper, the effects of chitosan 1% and 1.5% on the shelf life and postharvest quality characteristics of banana fruits stored at 34 ± 1°C and 70-75% relative humidity, while uncoated fruits served as a control were evaluated.
Abstract: The effects of chitosan 1% and 1.5%, calcium chloride (CaCl2) 1% and 1.5%, chitosan 1% + gibberellic acid 100 ppm, chitosan 1.5% + gibberellic acid 100 ppm, jojoba wax, and glycerol (98%) coatings were evaluated on the shelf life and postharvest quality characteristics of banana fruits stored at 34 ± 1°C and 70–75% relative humidity, while uncoated fruits served as a control. The coatings of chitosan, chitosan + gibberellic acid, and jojoba wax delayed the changes in the weight loss percentage, decay percentage, total soluble solids, pH, titrable acidity, sugar accumulation, pigment degradation, and ascorbic acid compared to uncoated ones. Further, the least disease incidence was found to occur in the banana fruits treated with chitosan and chitosan + gibberellic acid. Hence, it can be concluded that coating with chitosan and chitosan + gibberellic acid has the potential to control decay percentage, prolong the shelf life, and preserve valuable attributes of banana. Calcium chloride and glycerol coatings ...
TL;DR: According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.
Abstract: For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L−1 and 500 mg·L−1 and combinational treatment of scarification with gibberellic acid of 250 mg·L−1 and 500 mg·L−1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.
TL;DR: Analysis of subtracted cDNA libraries prepared using the RNA isolated from the apical bud and the associated two leaves of actively growing AG and winter dormant plant showed the downregulation of genes involved in cell cycle/cell division and upregulation of stress-inducible genes including those encoding chaperons during WD.
Abstract: Gene networks modulated in winter dormancy (WD) in relation to temperature and hormone responses were analyzed in tea [Camellia sinensis (L.) O. Kuntze]. Analysis of subtracted cDNA libraries prepared using the RNA isolated from the apical bud and the associated two leaves (two and a bud, TAB) of actively growing (AG) and winter dormant plant showed the downregulation of genes involved in cell cycle/cell division and upregulation of stress-inducible genes including those encoding chaperons during WD. Low temperature (4°C) modulated gene expression in AG cut-shoots in similar fashion as observed in TAB during WD. In tissue harvested during WD, growth temperature (25°C) modulated gene expression in the similar way as observed during the period of active growth (PAG). Abscisic acid (ABA) and gibberellic acid (GA3) modulated expression of selected genes, depending upon if the tissue was harvested during PAG or WD. Tissue preparedness was critical for ABA- and GA3-mediated response, particularly for stress-responsive genes/chaperons. Data identified the common gene networks for winter dormancy, temperature, and plant hormone responses.
TL;DR: Methods of scratching the seed coat with iron particles and treating the whole seeds with concentrated H2SO4, ultrasonic waves and gamma rays were employed for breaking the seed dormancy, and the effect of gamma irradiation on the growth of caper shoots in vitro was studied.
TL;DR: Seeds of this species showed non-deep simple (root) - non- deep simple (epicotyl) morphophysiological dormancy, highlighting a high synchronisation with Mediterranean seasonality in all the investigated populations.
Abstract: Morphophysiological dormancy was investigated in seeds of Ribes multiflorum Kit ex Roem et Schult ssp sandalioticum Arrigoni, a rare mountain species endemic to Sardinia (Italy) There were no differences in imbibition rates between intact and scarified seeds, suggesting a lack of physical dormancy, while methylene blue solution (05%) highlighted a preferential pathway for solution entrance through the raphe Embryos were small at seed dispersal, with an initial embryo:seed ratio (E:S) of ca 02 (embryo length, ca 05 mm), whereas the critical E:S ratio for germination was three times longer (ca 06) Gibberellic acid (GA(3), 250 mg · l(-1)) and warm stratification (25 °C for 3 months) followed by low temperature (<15 °C) enhanced embryo growth rate (maximum of ca 004 mm · day(-1) at 10 °C) and subsequent seed germination (radicle emergence; ca 80% at 10 °C) Low germination occurred at warmer temperatures, and cold stratification (5 °C for 3 months) induced secondary dormancy After radicle emergence, epicotyl emergence was delayed for ca 2 months for seeds from three different populations Mean time of epicotyl emergence was affected by GA(3) Seeds of this species showed non-deep simple (root) - non-deep simple (epicotyl) morphophysiological dormancy, highlighting a high synchronisation with Mediterranean seasonality in all the investigated populations
TL;DR: GA3 treatment had opposite effect on primary terpenoid biosynthesis by the plastidic 2C-methyl-d-erythritol 4-phosphate (MEP) and mevalonates (MVA) pathways, but secondary terpenoids showed different response to GA3 treatment probably due to interference of two biosynthetic pathways in their formation.
Abstract: In this study the influence of gibberellic acid (GA3) on plastidic and cytosolic terpenoids and on two key enzymes, 1-deoxy-d-xylulose-5-phosphate synthase (DXS) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), for terpenoid biosynthesis was compared in vegetative cannabis plants. Treatment with GA3 resulted in a decrease of DXS activity in comparison with the control plants. The amount of chlorophylls a, b and total carotenoids declined when plants treated by GA3 in a concentration dependent manner. The α-tocopherol content of cannabis plants decreased in 50 μM GA3 treatment and increased in 100 μM GA3 treatment. Exogenous GA3 caused an increase in HMGR activity. Concomitant with this result, the amount of squalene and phytosterols increased with GA3 treatment. The amount of THC and CBD did not change at 50 μM GA3 treatment, but applying of 100 μM GA3 increased THC and CBD content in leaf plant in comparison with control plants. GA3 treatment declined number and percentage of monoterpenes in treated plants. Also the number of sesquiterpenes decreased in response to GA3 treatment but among the remainder of them, the amount of some sesquiterpenes decreased and some sesquiterpenes increased with GA3 treatment. Our results showed that GA3 treatment had opposite effect on primary terpenoid biosynthesis by the plastidic 2C-methyl-d-erythritol 4-phosphate (MEP) and mevalonate (MVA) pathways. But secondary terpenoids showed different response to GA3 treatment probably due to interference of two biosynthetic pathways in their formation.
TL;DR: In this paper, the influence of various agricultural chemicals such as fertilizers, pesticides and growth regulators on rice aroma and flavor was examined using two aromatic rice cultivars and the results demonstrated that treatments with growth regulators inhibited the metabolic processes associated with the formation of volatile compounds.
Abstract: Aromatic rices (Oryza sativa L.) compared to the leading varieties are low-yielding, susceptible to lodging and prone to attack by a number of insect pests and diseases. Under these conditions, various agricultural chemicals such as fertilizers, pesticides and growth regulators have been used for their cultivation. Few investigations, however, have examined the influence of these chemicals on rice aroma and flavor. In this study, changes in rice aroma after treatment with gibberellic acid, paclobutrazol, 3-indole acetic acid, and a regulator mixture consisting of paclobutrazol, proline and zinc chloride were for the first time examined using two aromatic rice cultivars. Applications were carried out after 25% of panicles had emerged. We studied 12 odor-active compounds, extracted and identified using static headspace coupled with gas chromatography. At the concentrations tested, all treatments with growth regulators resulted in reduced aroma content that affected overall flavor. In a smelling evaluation, control samples were significantly higher in intensity than treated samples. The difference between the aromas of control and treated samples was largely related to 2-acetyl-1-pyrroline, the major rice aroma compound, and lipid oxidation volatiles. For instance, in the cultivar Guixiangzhan grown during the late season, gibberellic acid treatment decreased the content of 2-acetyl-1-pyrroline by 19%, 3-indole acetic acid by 9%, paclobutrazol by 22%, and the regulator mixture by 21% compared with the control. Similar trends were observed in the Peizaruanxiang cultivar, with decreases ranging from 10 to 24%. Our findings demonstrate that treatments with growth regulators inhibited the metabolic processes associated with the formation of volatile compounds.
TL;DR: Findings indicate that PvRACK1 has a pivotal role in cell expansion and in symbiosome and bacteroid integrity during nodule development and that infected and uninfected cells were considerably smaller than in control nodules.
Abstract: Receptor for activated C kinase (RACK1) is a highly conserved, eukaryotic protein of the WD-40 repeat family. Its peculiar β-propeller structure allows its interaction with multiple proteins in various plant signal-transduction pathways, including those arising from hormone responses, development, and environmental stress. During Phaseolus vulgaris root development, RACK1 (PvRACK1) mRNA expression was induced by auxins, abscissic acid, cytokinin, and gibberellic acid. In addition, during P. vulgaris nodule development, PvRACK1 mRNA was highly accumulated at 12 to 15 days postinoculation, suggesting an important role after nodule meristem initiation and Rhizobium nodule infection. PvRACK1 transcript accumulation was downregulated by a specific RNA interference construct which was expressed in transgenic roots of composite plants of P. vulgaris inoculated with Rhizobium tropici. PvRACK1 downregulated transcript levels were monitored by quantitative reverse-transcription polymerase chain reaction analysis in...
TL;DR: Although treatment with GA3 had little effect on the total soluble solids and fruit juice pH, it increased the vitamin C content and histological observations indicated that the increase of fruit volume and flesh weight under this GA3 treatment was not due to the increased of cell number but a result of the increase in cell area in the fruit flesh.
Abstract: In mainland China, the most popular pineapple cultivar is ‘Comte de Paris’. Gibberellic acids have been widely applied to enhance fruit growth in various species. To evaluate the effect of gibberellic acid (GA3) on ‘Comte de Paris’ pineapple production and quality, pineapple fruits were sprayed with GA3 at concentrations of 5, 20, 50, or 100 mg l−1 at both 0 and 15 days after flowering (DAF). Fruits were sampled every 15 days from 0 to 60 DAF (maturation) for flow cytometric analysis and histological observation. The results showed that the treatments with the three highest concentrations of GA3 significantly increased fruit weight, and the most effective concentration was 50 mg l−1 GA3, which increased the flesh weight by 20.3% compared to the control. Although treatment with GA3 had little effect on the total soluble solids and fruit juice pH, it increased the vitamin C content. Although flow cytometric analysis showed that the 50 mg l−1 GA3 treatment had only a slight impact on the number of S phase cells, histological observations indicated that the increase of fruit volume and flesh weight under this GA3 treatment was not due to the increase of cell number but a result of the increase of cell area in the fruit flesh.
TL;DR: The goal of the trials reported here was to determine the potential for stimulating lateral branching by applying gibberellic acid alone under similar conditions, and to combine the surfactant Pentra-bark with gibb Berellic Acid to result in successful branch induction without the need to apply gibbrellic acids to scoring or nicking cuts in the bark.
Abstract: Previous studies showed that successful stimulation of lateral branch development from 1-year-old wood in young sweet cherry trees without reliance on pruning could be accomplished if suitable cytokinin- or cytokinin/gibberellic acid-containing products were applied to assure penetration into active tissues. The goal of the trials reported here was to determine the potential for stimulating lateral branching by applying gibberellic acid alone under similar conditions. Three commercially available products containing gibberellic acid were evaluated. Treatments included the isomers GA3, GA4, and GA4 combined with GA7. All gibberellic acid isomer/formulations were similar in their ability to stimulate branching from lateral buds on 1-year-old wood. In one trial, GA4+7 alone was nearly as effective as the cytokinin 6-benzyladenine. Combining the surfactant Pentra-bark with gibberellic acid resulted in successful branch induction without the need to apply gibberellic acid to scoring or nicking cuts in the bark.
TL;DR: Effect of different chemical treatments on quantitative characteristics of Polianthes tuberose L. (cv. Goldorosht Mahallat) was investigated and showed that, flowering stem length and leaves length were greatest with GA3 at 100 ppm while BA no increase these traits compared to the control.
Abstract: Effect of different chemical treatments on quantitative characteristics of Polianthes tuberose L. (cv. Goldorosht Mahallat) was investigated. This research was conducted in a factorial experiment based on block design with 3 replications. 40 and 54 days after planting, the flowers were sprayed with various concentrations of Gibberellic acid (GA3) and Benzyladenine (BA) (0, 50, and 100 ppm). The results showed that, flowering stem length and leaves length were greatest with GA3 at 100 ppm while BA no increase these traits compared to the control. GA3 resulted in earlier flowering compared to the control. BA and GA3 decreased number of floret. Greatest diameter of floret and vase life of cut flower was BA at 50 and 100 ppm, respectively.
Journal Article•
TL;DR: The effects of temperature regime, photoperiod and gibberellic acid were significant and generally had the lowest percentage of seed germination of T. sericea.
Abstract: In an effort to improve and promote the propagation of Terminalia sericea, the effects of temperature, photoperiod and growth regulators on seed germination were investigated. Seeds were tested with different temperature regime (10, 15, 20, 25, 30, 35 and 40oC) and in photoperiod (4/20, 8/16, 12/12, 16/8 light/dark hrs and 24 hours continuous dark). Pre-treatments with growth regulators were done with solutions of gibberellic acid (GA3) at (50, 100, 200, 400 ppm) and potassium nitrate (KNO3) at (2000, 4000, 6000, 8000 ppm). The effects of temperature regime, photoperiod and gibberellic acid were significant (p< 0.001). Optimum temperature regime was found at 25°C with germination 35% while photoperiod of 12/12 light/dark hr had relatively high germination 33%. Highest germination 67% was obtained with pre treatment of GA3 at 400 ppm. Pre treatments with KNO3 had insignificant effect and generally had the lowest percentage of seed germination. These results have significant implication on the best methods to be used in improving seed germination of T. sericea.
TL;DR: The use of oxygenated peptone is recommended being less expensive and usable under organic farming condition as it does not enter the plant metabolic pathways and yet brings about significant positive effect.
Abstract: The experiments were carried out at the Post Graduate Research Center, to study the influence of Gibberellic Acid (50 ppm) and Oxygenated Peptone (1% aqueous solution) on chick pea (Cicer arietinum L. cv. Vijay) during germination by giving pre-sowing soaking treatment for 6 hours using petriplate method. Both the treatments enhanced the germination process. GA treatment was useful to increase shoot length, mobilization efficiency, emergence index, speed of germination and co-efficient of germination while oxygenated peptone showed an upper hand in root length, shoot/root ratio, biomass and vigour index. GA led to comparatively more synthesis of nucleic acids while oxygenated peptone showed more increase in total carbohydrates and soluble protein content. However, the activity of enzymes like amylase, catalase and protease showed upper hand with oxygenated peptone as compared to GA. In fact GA is costlier and can not be used in organic farming as it enters metabolic pathways of plant and alters them. Hence the use of oxygenated peptone is recommended being less expensive and usable under organic farming condition as it does not enter the plant metabolic pathways and yet brings about significant positive effect.
TL;DR: The data obtained confirm previous findings, that ultrahigh diluted potentized gibberellic acid affects stalk growth, and suggests that experiments utilizing the bioassay presented should best be performed in autumn season.
Abstract: The influence of a homeopathic high dilution of gibberellic acid on wheat growth was studied at different seasons of the year. Seedlings were allowed to develop under standardized conditions for 7 days; plants were harvested and stalk lengths were measured. The data obtained confirm previous findings, that ultrahigh diluted potentized gibberellic acid affects stalk growth. Furthermore, the outcome of the study suggests that experiments utilizing the bioassay presented should best be performed in autumn season. In winter and spring, respectively, no reliable effects were found.
TL;DR: MS medium supplemented with 5 mg l−1 BAP and coconut water (15%) was the most efficient media for shoot initiation and multiple shoot formation (15 shoots from a single part of a floral bud) and the best response for shoot elongation was obtained.
Abstract: In vitro propagation has played a key role for obtaining large numbers of virus free, homogenous plants, and for breeding of plantains and bananas (Musa spp.). Explant sources utilized for banana micropropagation include suckers, shoot tips, and floral buds. The present study employed male floral meristems as explant material for micropropagation of hill banana ecotypes (AAB) ‘Virupakshi’ and ‘Sirumalai.’ Immature male floral buds were collected from healthy plants from hill banana growing areas. Exposure of explants to ethyl alcohol (70%, v/v) for 30 s, then mercuric chloride (0.1%, w/v) for 30 s, followed by three independent rinses of 5 min each in autoclaved, double-distilled water satisfactorily reduced the contamination. Male floral bud explants were cultured on Murashige and Skoog (MS) basal medium supplemented with different combinations of 6-benzylaminopurine (BAP), coconut water, naphthaleneacetic acid, gibberellic acid, and additional supplements. MS medium supplemented with 5 mg l−1 BAP and coconut water (15%) was the most efficient media for shoot initiation and multiple shoot formation (15 shoots from a single part of a floral bud). The best response for shoot elongation was obtained using the combination of basal MS, 5 mg l−1 BAP, 1 mg l−1 naphthaleneacetic acid and 1.5 mg l−1 gibberellic acid. Regenerated shoots were rooted in basal MS medium within 15–20 d. The rooted plantlets were transferred to a soil mixture and maintained at a temperature of 25 ± 2°C for 10 d and then at room temperature (30–32°C) for 2 wk, before transferring to a greenhouse. The regenerated plantlets showed 100% survival.
TL;DR: Acid scarification of seeds stored up to nine months, followed by the gibberellic acid treatment, or the storage of seeds up to 21 months resulted in a 60% germination rate, which is more effective for dormancy release than the acid scarification or the application of germination promoters.
Abstract: Most of the tropical forages is affected by seed dormancy, which can hinder the determination of its physiological quality, field seedling emergence, and the establishment of pastures. This study aimed to evaluate the effectiveness of acid scarification and application of germination promoters on the dormancy release of stored seeds of Brachiaria humidicola . Seeds stored during nine and 21 months were scarified with the aid of concentrated sulfuric acid. Afterwards, the seeds were placed to germinate on a blotter paper moistened with the following solutions: KNO 3 (0.2%), gibberellic acid (100 mg L -1 ), H 2 O 2 (0.30%), and distilled water. The seeds remained for 21 days under an alternating temperatures regime (15-35oC) and light cycles (8 hours of light/16 hours of darkness), when the percentages of germination and dormant seeds were evaluated. Acid scarification was more effective on dormancy release in the seeds stored up to nine months, in comparison to the ones stored for 21 months, with reduction of dormant seeds percentage from 84% to 36%. Acid scarification of seeds stored up to nine months, followed by the gibberellic acid treatment, or the storage of seeds up to 21 months resulted in a 60% germination rate. The storage of B. humidicola seeds up to 21 months is more effective for dormancy release than the acid scarification or the application of germination promoters.
TL;DR: Overall, 90% of the plantlets derived from stored and non-stored synthetic seeds survived in the greenhouse and grew to phenotypically normal plants and can enable the use of synthetic seed technology for germplasm conservation of S. officinalis, a plant species of high medical and commercial value.
Abstract: Shoot tips excised from shoot culture of Salvia officinalis were encapsulated in 2% or 3% (w/v) sodium alginate and exposed to 50 mM calcium chloride for complexation. Immediately or after 6, 12 or 24 weeks of storage at 4°C, the synthetic seeds were cultured for 6 weeks on half-strength MS medium supplemented with indole-3acetic acid (IAA) (0.1 mg/l) and solidified with 0.7% agar. The frequency of shoot and root emergence from encapsulated shoot tips was affected by the concentrations of sodium alginate and additives in the gel matrix (sucrose, gibberellic acid, MS nutrient medium) as well as duration of storage. The frequency of shoot and root induction of non-stored synthetic seeds was highest with shoot tips encapsulated with 2% sodium alginate containing 1.5% sucrose and 0.5 mg/l gibberellic acid (GA3). Shoot tips maintained their viability and ability to develop shoots even after 24 weeks of storage when they were encapsulated in 3% alginate with 1/3 MS medium, sucrose (1.5%) and GA3 (0.25 mg/l). Root formation tended to decrease with storage time. Overall, 90% of the plantlets derived from stored and non-stored synthetic seeds survived in the greenhouse and grew to phenotypically normal plants. This procedure can enable the use of synthetic seed technology for germplasm conservation of S. officinalis, a plant species of high medical and commercial value.
Journal Article•
TL;DR: The postharvest behavior of Gladiolus was studied on White Prosperity cultivars to increase longevity of cut flowers and showed that the soluble sugar content increased in both of the petals and leaves in 5 day after harvest.
Abstract: 4 Abstract: Cytokine and gibberellic acid have been reported in several studies to improve the postharvest vase life of many cut flowers. Foliar application of nutrients and plant growth regulators may improve flower quality parameters. In this study the postharvest behavior of Gladiolus was studied on White Prosperity cultivars to increase longevity of cut flowers. Primarily bulbs were treated with four different concentrations of benzyladenine (0, 100, 150, 200 mg/l) and gibberellic acid (GA ) (0, 50, 100, 150mg/l) solely for 6 hours then 3 planted. After 1, 5 and 10 days after harvest. Evaluations of carbohydrate, protein and chlorophyll content in the leaf and petals were done. The results showed that the soluble sugar content increased in both of the petals and leaves in 5 day after harvest. Soluble sugars content in leaves were higher than the petals in 5 day after th th