Showing papers on "Gibberellic acid published in 2010"
TL;DR: Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination and mediating hormone effects.
Abstract: As an important agronomic trait, inclination of leaves is crucial for crop architecture and grain yields. To understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 (lc2, three alleles) mutant was identified and functionally characterized. Compared to wild-type plants, lc2 mutants have enlarged leaf angles due to increased cell division in the adaxial epidermis of lamina joint. The LC2 gene was isolated through positional cloning, and encodes a vernalization insensitive 3-like protein. Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination. LC2 is mainly expressed in the lamina joint during leaf development, and particularly, is induced by the phytohormones abscisic acid, gibberellic acid, auxin, and brassinosteroids. LC2 is localized in the nucleus and defects of LC2 result in altered expression of cell division and hormone-responsive genes, indicating an important role of LC2 in regulating leaf inclination and mediating hormone effects.
140 citations
TL;DR: It was concluded that GA(3) ameliorates the adverse effects of salt stress and restores normal growth and development of soybean.
Abstract: The agricultural industry is severely affected by salinity due to its high magnitude of adverse impacts and worldwide distribution. We observed the role of exogenous gibberellic acid (GA3) in salin...
140 citations
TL;DR: Assay of antioxidant activity of in vitro and in vivo grown tissues revealed that significantly higher antioxidant activity was observed in callus than all other regenerated tissues and wild-grown plants.
Abstract: The morphogenic potential and free-radical scavenging activity of the medicinal plant, Silybum marianum L. (milk thistle) were investigated. Callus development and shoot organogenesis were induced from leaf explants of wild-grown plants incubated on media supplemented with different plant growth regulators (PGRs). The highest frequency of callus induction was observed on explants incubated on Murashige and Skoog (MS) medium supplemented with 5.0 mg l−1 6-benzyladenine (BA) after 20 days of culture. Subsequent transfer of callogenic explants onto MS medium supplemented with 2.0 mg l−1 gibberellic acid (GA3) and 1.0 mg l−1 α-naphthaleneacetic acid (NAA) resulted in 25.5 ± 2.0 shoots per culture flask after 30 days following culture. Moreover, when shoots were transferred to an elongation medium, the longest shoots were observed on MS medium supplemented with 0.5 mg l−1 BA and 1.0 mg l−1 NAA, and these shoots were rooted on a PGR-free MS basal medium. Assay of antioxidant activity of in vitro and in vivo grown tissues revealed that significantly higher antioxidant activity was observed in callus than all other regenerated tissues and wild-grown plants.
96 citations
TL;DR: Results indicate that combination of triacontanol and gibberellic acid significantly increased activities of nitrate reductase and carbonic anhydrase, and net photosynthetic rate, stomatal conductance and internal CO2, and significantly enhanced artemisinin content and yield of Artemisia.
Abstract: Artemisia annua L. is an aromatic-antibacterial herb that destroys malarial parasites, lowers fevers and checks bleeding, and of which the secondary compound of interest is artemisinin. Enhanced production of the artemisinin content in the whole plant is highly desirable. Keeping in mind, the importance of this valuable antimalarial plant, field experiments were conducted to investigate the effects of triacontanol alone and in combination with gibberellic acid on growth attributes, photosynthesis, enzymatic activities, essential oil and artemisinin content and yield of Artemisia. The results indicate that combination of triacontanol and gibberellic acid (1.5 mg l−1+75 mg l−1) significantly increased activities of nitrate reductase and carbonic anhydrase by 25.9% and 21.5%, and net photosynthetic rate, stomatal conductance and internal CO2 by 25.4%, 14.1% and 15.4% higher, respectively, when compared to unsprayed plants. This combined treatment also significantly enhanced artemisinin content and y...
94 citations
TL;DR: An efficient and reproducible in vitro plant regeneration system from shoot apices was developed in Jatropha curcas and the integration of the transgene into genomic DNA of transgenic plants was confirmed by PCR and Southern blot hybridization.
Abstract: An efficient and reproducible in vitro plant regeneration system from shoot apices was developed in Jatropha curcas. Benzylaminopurine (BAP; 2.5 μM) was most effective in inducing an average of 6.2 shoots per shoot apex. Incorporation of gibberellic acid (GA3; 0.5 μM) to basal medium was found essential for elongation of shoots. The BAP-habituated mother explants continuously produced shoots during successive subculture without any loss of morphogenic potential. The shoots rooted efficiently on half-strength MS medium. The rooted plantlets were acclimatized with more than 98 % success and the plants transferred to soil:compost in nursery showed no sign of variation compared to the seed-grown plants. The whole process of culture initiation to plant establishment was accomplished within 5–6 weeks. A genetic transformation system in J. curcas was established for the first time, using bombardment of particles coated with plasmid pBI426 with a GUS-NPT II fusion protein under the control of a double 35S cauliflower mosaic virus (CaMV) promoter. The β-glucuronidase (GUS) activity in J. curcas shoot apices was significantly affected by the gold particle size, bombardment pressure, target distance, macrocarrier travel distance, number of bombardments, and type and duration of osmotic pre-treatment. The proliferating bombarded shoot apices were screened on medium supplemented with 25 mg dm−3 kanamycin and surviving shoots were rooted on medium devoid of kanamycin. The integration of the transgene into genomic DNA of transgenic plants was confirmed by PCR and Southern blot hybridization. The transgenic plants showed insertion of single to multiple copies of the transgene.
88 citations
TL;DR: In this paper, the authors employed a comparative proteomic analysis to elucidate the mechanism of GA3 activity in this phenomenon and found that GA3 reduced NaCl-induced growth inhibition in rice (Oryza sativa L. cv. Nipponbare).
78 citations
TL;DR: It was determined that all of these plant growth regulators (PGRs) decreased mitotic index in root tips of barley seeds germinated at 20 °C and in distilled water and some of the PGRs studied increased significantly the frequency of chromosomal aberrations.
Abstract: The effects of gibberellic acid (GA3), kinetin (KIN), benzyladenine and ethylene (E) on mitotic activity and chromosomal aberrations in root tips of barley seeds (Hordeum vulgare L. cv. “Bulbul 89”) germinated under salt stress were investigated. It was determined that all of these plant growth regulators (PGRs) decreased mitotic index in root tips of barley seeds germinated at 20 °C and in distilled water. Furthermore, some of the PGRs studied increased significantly the frequency of chromosomal aberrations. The frequency of chromosomal aberrations in seeds treated with E and KIN was considerably higher than in the seeds germinated under nonstress conditions. The inhibitory effect of salt stress on mitotic index increased with increasing salt concentration (0.30, 0.35, 0.40 and 0.45 molal, m). GA3 and KIN pretreatments showed a successful performance in ameliorating the negative effects of increasing salinity on mitotic activity. The number of chromosomal aberrations also increased with increasing NaCl concentration. However, most of the PGR pretreatments studied alleviated the detrimental effects of increasing salinity on chromosomal aberrations. KIN pretreatment at 0.30 and 0.35 m salinity could not rescued the cytogenetic activity of salt stress on this parameter.
65 citations
TL;DR: Rapid and high multiplication frequency, molecular, genetic and essential oil content stability ensure the efficacy of the protocol developed for the production of this industrially important aromatic plant.
63 citations
TL;DR: Sub-network analysis identified expression targets and binding partners associated with circadian clock, dehydration/cold signaling, phosphorylation cascades, and response to abscisic acid, ethylene, gibberellic Acid, and jasmonic acid suggesting these central regulators affect well-defined phases of dormancy and flowering.
Abstract: Leafy spurge (Euphorbia esula) is an herbaceous perennial weed that produces vegetatively from an abundance of underground adventitious buds. In this study, we report the effects of different environmental conditions on vegetative production and flowering competence, and determine molecular mechanisms associated with dormancy transitions under controlled conditions. Reduction in temperature (27–10°C) and photoperiod (16–8 h) over a 3-month period induced a para- to endo-dormant transition in crown buds. An additional 11 weeks of cold (5–7°C) and short-photoperiod resulted in accelerated shoot growth from crown buds, and 99% floral competence when plants were returned to growth-promoting conditions. Exposure of paradormant plants to short-photoperiod and prolonged cold treatment alone had minimal affect on growth potential and resulted in ~1% flowering. Likewise, endodormant crown buds without prolonged cold treatment displayed delayed shoot growth and ~2% flowering when returned to growth-promoting conditions. Transcriptome analysis revealed that 373 and 260 genes were differentially expressed (P < 0.005) during para- to endo-dormant and endo- to eco-dormant transitions, respectively. Transcripts from flower competent vs. non-flower competent crown buds identified 607 differentially expressed genes. Further, sub-network analysis identified expression targets and binding partners associated with circadian clock, dehydration/cold signaling, phosphorylation cascades, and response to abscisic acid, ethylene, gibberellic acid, and jasmonic acid, suggesting these central regulators affect well-defined phases of dormancy and flowering. Potential genetic pathways associated with these dormancy transitions and flowering were used to develop a proposed conceptual model.
57 citations
01 Jan 2010
TL;DR: It might be concluded that, SA could eliminate the adverse effects of cold stress in common bean and stimulated various growth aspects of bean seedlings perhaps through interference with the enzymatic activities responsible for biosynthesis and/or catabolism of growth promoting and inhibiting substances.
Abstract: An experiment was carried out under laboratory condition to tackle low temperature stress by using salicylic acid (SA). Seeds of six common bean varieties (Polista, Nebraska, Goro, Helda, Duel and Giza 6) were soaked in water or 10 −4 M aerated solution of salicylic acid (SA) for 6 h. Treated and untreated seeds were germinated at 25 ○ C (optimal temperature) and at 15 ○ C (suboptimal temperature or chilling stress) under dark controlled conditions for 9 and 30 days , respectively. Germination and seedling growth of the six tested varieties were significantly hindered under low temperature. Seed treatments with SA significantly improved germination percentage, germination rate and seedling criteria, compared with control seeds under optimal and low temperature stress conditions. The content of Indolacetic acid (IAA), Gibberellic acid (GA3) and Abscisic acid (ABA) increased in the different varieties under study, in response to seed soaking in 10 −4 M SA at 15°C. GA3/ABA ratio showed maximum increase in Duel and Helda, while the lowest ratio was observed in Giza 6 and Nebraska seedlings. At the same low temperature, catalase activity was decreased, whereas that of polyphenol oxidase increased on using 10 -4 M SA. Peroxidase isozymes indicated five to three isozymes in seedlings of the six bean varieties. Salicylic acid treatment resulted in detecting (in Duel) and disappearance (in Nebraska) of peroxidase isozymes at Rf: 0.37, which might be responsible for tolerance and sensitivity mechanism, respectively. The present results indicated that, salicylic acid stimulated various growth aspects of bean seedlings perhaps through interference with the enzymatic activities responsible for biosynthesis and/or catabolism of growth promoting and inhibiting substances. Thus, it might be concluded that, SA could eliminate the adverse effects of cold stress in common bean. (Journal of American Science 2010;6(10):675-683). (ISSN: 1545-1003).
57 citations
Journal Article•
TL;DR: The effects of incubation time, temperature, pH, and agitation on indole-3- acetic acid and gibberellic acid production in Aspergillus niger were studied.
Abstract: The effects of incubation time, temperature, pH, and agitation on indole-3- acetic acid and gibberellic acid production in Aspergillus niger were studied. For indole-3-acetic acid production, 6 days of incubation at 25 °C and pH 6.0 was found to be optimum. Optimum conditions for gibberellic acid production were 12 days of incubation at 30 °C and pH 5.0. Agitation increased both indole-3-acetic acid and gibberellic acid production.
TL;DR: It was showed that co-inoculation of Bradyrhizobium and Pseudomonas strains with the P2O5 treatment resulted in increased grain yield of 38% in pot experiments and 12% in the field experiment, compared with theP2O 5 treatment alone.
Abstract: Phosphorus availability for soybean growth is frequently low because P reacts with iron, aluminum and calcium in soil to form insoluble phosphates. The increasing price of phosphatic fertilizers is a major obstacle faced by farmers for application of recommended P doses. Low yield of soybean in Pakistan is also lowering adoption by farmers of this oilseed crop. These issues could be solved by inoculation of beneficial microorganisms that enhance the availability of N and P to the plant. Here, we tested the effect of inoculation of Bradyrhizobium or Pseudomonas, or both, in the presence and absence of P2O5 fertilizer, on soybean yield. Experiments were carried out in pots and the field during 2004 and 2005 under natural conditions. The bacterial strains were applied in broth culture in the pots at the seedling stage or as a seed treatment in the field. Our results showed that co-inoculation of Bradyrhizobium and Pseudomonas strains with the P2O5 treatment resulted in increased grain yield of 38% in pot experiments and 12% in the field experiment, compared with the P2O5 treatment alone. Bradyrhizobium japonicum strain TAL 377 produced 74.64 μg/mL indole acetic acid and 261.2 μg/mL gibberellic acid. Similarly, Pseudomonas strain 54RB produced 8.034 μg/mL indole acetic acid and 1766 μg/mL gibberellic acid. The survival efficiency of Bradyrhizobium was up to 46% higher due to co-inoculation and P2O5 as compared with its single inoculation. On the other hand, Pseudomonas survival efficiency was up to 33% higher with added P2O5 as compared with its single inoculation.
TL;DR: This work investigated the transport of apple (Malus x domestica cv. Fuji and Malus xiaojinensis) endogenous GAI mRNA by grafting experiments and found that the GAI RNA moves in both upward and downward directions via the graft union.
Abstract: The sieve tube in higher plants functions as infrastructure for long-distance transport of nutrients, photoassimilates, and growth regulators including hormones. Recently, it was revealed that some protein and RNA molecules also function as movable growth regulators in the sieve tube. In the case of the mRNA of gibberellic acid insensitive (GAI), the transport evidence was obtained through identification of the overproduced transgene transcript. In this work, we investigated the transport of apple (Malus x domestica cv. Fuji and Malus xiaojinensis) endogenous GAI mRNA by grafting experiments. Each GAI mRNA of scion and stock plants was detected in the graft partners as from 5 days after grafting, indicating that the GAI mRNA moves in both upward and downward directions via the graft union.
TL;DR: Observations indicate that SA promotes seed germination under high salinity by modulating antioxidant activity through signaling crosstalks with GA, indicating that SA is involved in plant responses to ROS-mediated damage under abiotic stress conditions.
Abstract: Potential roles of salicylic acid (SA) on seed germination have been explored in many plant species. However, it is still controversial how SA regulates seed germination, mainly because the results have been somewhat variable, depending on plant genotypes used and experimental conditions employed. We found that SA promotes seed germination under high salinity in Arabidopsis. Seed germination of the sid2 mutant, which has a defect in SA biosynthesis, is hypersensitive to high salinity, but the inhibitory effects are reduced in the presence of physiological concentrations of SA. Abiotic stresses, including high salinity, impose oxidative stress on plants. Endogenous contents of H(2)O(2) are higher in the sid2 mutant seeds. However, exogenous application of SA reduces endogenous level of reactive oxygen species (ROS), indicating that SA is involved in plant responses to ROS-mediated damage under abiotic stress conditions. Gibberellic acid (GA), a plant hormone closely associated with seed germination, also reverses the inhibitory effects of high salinity on seed germination and seedling establishment. Under high salinity, GA stimulates SA biosynthesis by inducing the SID2 gene. Notably, SA also induces genes encoding GA biosynthetic enzymes. These observations indicate that SA promotes seed germination under high salinity by modulating antioxidant activity through signaling crosstalks with GA.
01 Jan 2010
TL;DR: In this paper, the authors identified the signal transduction component that causes response variation in shoot elongation among two accessions of the wetland plant Rumex palustris, and they found that the level of ethylene-regulated abscisic acid in petioles, and hence gibberellic acid responsiveness, explained the difference in shoot length upon submergence.
Abstract: Elongation of leaves and stem is a key trait for survival of terrestrial plants during shallow but prolonged floods that completely submerge the shoot. However, natural floods at different locations vary strongly in duration and depth, and, therefore, populations from these locations are subjected to different selection pressure, leading to intraspecific variation. Here, we identified the signal transduction component that causes response variation in shoot elongation among two accessions of the wetland plant Rumex palustris. These accessions differed 2-fold in petiole elongation rates upon submergence, with fast elongation found in a population from a river floodplain and slow elongation in plants from a lake bank. Fast petiole elongation under water consumes carbohydrates and depends on the (inter)action of the plant hormones ethylene, abscisic acid, and gibberellic acid. We found that carbohydrate levels and dynamics in shoots did not differ between the fast and slow elongating plants, but that the level of ethylene-regulated abscisic acid in petioles, and hence gibberellic acid responsiveness of these petioles explained the difference in shoot elongation upon submergence. Since this is the exact signal transduction level that also explains the variation in flooding-induced shoot elongation among plant species (namely, R. palustris and Rumex acetosa), we suggest that natural selection results in similar modification of regulatory pathways within and between species.
TL;DR: In this article, a C-terminal domain (CTD) was identified that negatively regulates mRNA and protein levels, and mediates sensitivity to ABA and GA by an uncharacterized mechanism.
Abstract: The transcription factor FUSCA3 (FUS3) controls the transition from the embryonic to the vegetative phase of development by regulating abscisic acid (ABA) and gibberellic acid (GA) levels in Arabidopsis thaliana. In a feedback loop, FUS3 accumulation is negatively and positively regulated by GA and ABA, respectively, by an uncharacterized mechanism. Here, we use a FUS3-GFP construct to show that the level of the FUS3 protein decreases dramatically during mid to late embryogenesis, whereas its mRNA is present at a high level. Deletion studies identify a C-terminal domain (CTD) that negatively regulates mRNA and protein levels, and mediates sensitivity to ABA and GA. Indeed, a CTD-truncated FUS3 variant accumulates at high level, and is insensitive to the destabilizing and stabilizing effects of GA and ABA, respectively. In contrast, fusion of various fragments of the CTD with GFP is sufficient to greatly reduce GFP fluorescence. The GFP-CTD fluorescence can be increased by ABA and paclobutrazol, an inhibitor of GA biosynthesis. Cell-free degradation assays show that FUS3 is a short-lived protein. FUS3 degradation follows the 26S proteasome in vitro and in vivo, and the CTD affects its degradation rate. In contrast to the native form, the CTD-truncated FUS3 is unable to fully rescue the fus3-3 mutant, and is thus required for FUS3 function. In conclusion, this study identifies a CTD that maintains low levels of FUS3 during embryogenesis and early germination, and is required for normal FUS3 function and sensitivity to ABA and GA.
TL;DR: The signal transduction component that causes response variation in shoot elongation among two accessions of the wetland plant Rumex palustris is identified and it is suggested that natural selection results in similar modification of regulatory pathways within and between species.
Abstract: Elongation of leaves and stem is a key trait for survival of terrestrial plants during shallow but prolonged floods that completely submerge the shoot. However, natural floods at different locations vary strongly in duration and depth, and, therefore, populations from these locations are subjected to different selection pressure, leading to intraspecific variation. Here, we identified the signal transduction component that causes response variation in shoot elongation among two accessions of the wetland plant Rumex palustris. These accessions differed 2-fold in petiole elongation rates upon submergence, with fast elongation found in a population from a river floodplain and slow elongation in plants from a lake bank. Fast petiole elongation under water consumes carbohydrates and depends on the (inter)action of the plant hormones ethylene, abscisic acid, and gibberellic acid. We found that carbohydrate levels and dynamics in shoots did not differ between the fast and slow elongating plants, but that the level of ethylene-regulated abscisic acid in petioles, and hence gibberellic acid responsiveness of these petioles explained the difference in shoot elongation upon submergence. Since this is the exact signal transduction level that also explains the variation in flooding-induced shoot elongation among plant species (namely, R. palustris and Rumex acetosa), we suggest that natural selection results in similar modification of regulatory pathways within and between species.
TL;DR: The amounts of two of the end products, 1,8-cineole and camphor, were directly correlated with the levels of gene expression of the respective monoterpene synthases, indicating transcriptional control, while the formation of alpha- and beta-thujone was not transcriptionally regulated.
TL;DR: Chlorophyll (Chl) degradation was found to be related to the endogenous gibberellin (GA) content in shoots during senescence in the perennial plant Paris polyphylla var.
Abstract: Chlorophyll (Chl) degradation was found to be related to the endogenous gibberellin (GA) content in shoots during senescence in the perennial plant Paris polyphylla var. yunnanensis (Franch.). Treatment with gibberellic acid (GA3) significantly increased the content of endogenous GAs (GA4 + GA7), retarded the senescence of shoots, and the degradation of proteins and Chl. Chlorophyllase, Mg-dechelation and peroxidase activities increased more in control plants than in those treated with GA3. GA3 treatment also protected lipoxygenase activity, which decreased significantly in control plants.
TL;DR: It is demonstrated that both, a membrane-permeant analogue of cGMP (8-Br-cGMP) and the cyclic nucleotide phosphodiesterase (PDE) inhibitor Tadalafil promoted A. thaliana seed germination, whereas the guanylate cyclase inhibitor LY 83583 (6-anilino-5,8-quinolinedione; LY) inhibited it.
01 Jan 2010
TL;DR: The effect of gibberellin on promoting stem growth was first discovered in 1930s by studies of the Bakanae(foolish seedling) disease in rice and analysis of their GA contents revealed that bioactive GAs are endogenous hormones that regulate the natural developmental processes including stem growth in plants.
Abstract: The effect of gibberellin (GA) on promoting stem growth was first discovered in 1930s by studies of the Bakanae(foolish seedling) disease in rice (57). Gibberella fujikuroi, a pathogenic fungus, produces gibberellic acid (GA3) that causes the infected rice plants to grow so tall that they fall over. Later studies of dwarf mutants and analysis of their GA contents revealed that bioactive GAs are endogenous hormones that regulate the natural developmental processes including stem growth in plants. An increase in both cell elongation and cell division occurs during stem growth. GA induces transcription of genes involved in these processes. For example, expression of some of the genes encoding xyloglucan endotransglycosylases (XETs1) and expansins are upregulated by GA in elongating internodes in rice and in Arabidopsis (7, 62, 66). XET is thought to increase the plasticity of the cell wall because this enzyme is involved in xyloglucan reorganization through cleaving and re-ligating xyloglucan polymers in the cell wall. Expansins are also extracellular proteins that cause plant cell wall loosening, probably by disrupting the polysaccharide adhesion. Transcripts of the genes encoding for cyclin-dependent protein kinases are also elevated in intercalary meristem in rice after GA treatment (12).
TL;DR: A protocol for Agrobacterium-mediated transformation was developed for in vitro leaf explants of an elite, mature Prunus serotina tree, and the results confirmed the presence of the neomycin phosphotransferase and AG genes.
Abstract: A protocol for Agrobacterium-mediated transformation was developed for in vitro leaf explants of an elite, mature Prunus serotina tree. Agrobacterium tumefaciens strain EHA105 harboring an RNAi plasmid with the black cherry AGAMOUS (AG) gene was used. Bacteria were induced for 12 h with 200 μM acetosyringone for vir gene induction before leaf explant inoculation. Explants were co-cultured for 3 days, and then cultured on woody plant medium supplemented with 9.08 μM thidiazuron, 1.07 μM napthaleneacetic acid, 60 μM silver thiosulphate, 3% sucrose, plus 200 mg l−1 timentin in darkness for 3 weeks. Regenerating shoots were selected 27 days after initial co-culture, on Murashige and Skoog medium with 3% sucrose, 8.88 μM 6-benzylaminopurine, 0.49 μM indole-3-butyric acid, 0.29 μM gibberellic acid, 200 mg l−1 timentin, and 30 mg l−1 kanamycin for five subcultures. After 5–6 months of selection, transformation efficiencies were determined, based on polymerase chain reaction (PCR) analysis of individual putative transformed shoots relative to the initial number of leaf explants tested. The transformation efficiency was 1.2%. Southern blot analysis of three out of four PCR-positive shoots confirmed the presence of the neomycin phosphotransferase and AG genes. Transgenic shoots were rooted (37.5%), but some shoot tips and leaves deteriorated or died, making acclimatization of rooted transgenic plants difficult. This transformation, regeneration, and rooting protocol for developing transgenic black cherry will continue to be evaluated in future experiments, in order to optimize the system for several mature black cherry genotypes.
TL;DR: The micropropagation of coconut palm has progressed rapidly; yet, there are constraints with regard to the number of somatic embryos formed and their germination, so the effect of gibberellic acid and characterized genes of the KNOX family were tested.
Abstract: The micropropagation of coconut palm has progressed rapidly; yet, there are constraints with regard to the number of somatic embryos formed and their germination. To overcome these, we tested the effect of gibberellic acid and characterized genes of the KNOX family. Gibberellic acid at 0.5 μM increased 1.5-fold the number of calli forming somatic embryos and twofold the number of somatic embryos per callus, calli with germinating embryos and the number of germinating somatic embryos per callus. With regard to the study of KNOX family genes, the complete sequences of two KNOX-like genes were obtained for CnKNOX1 and CnKNOX2. The deduced amino acid sequence of both showed highly conserved domains characteristic of KNOX genes. CnKNOX1 showed high homology with KNOX class I proteins. CnKNOX1 expression was detected throughout the embryogenesis process except in somatic embryos at the pro-globular stage, and was highest in somatic embryos at the coleoptilar stage. No detection of CnKNOX1 expression occurred in calli with aberrant embryos. The addition of gibberellic acid stimulated the expression of CnKNOX1 earlier and the relative expression at all stages was higher. CnKNOX2 expression occurred at all stages peaking at the globular stage, but gibberellic acid treatment decreased the expression. Gene expression was also analyzed in tissues of different organs of adult palms. With CnKNOX1, high level of expression was found in tissues of organs with, but not in those without, meristem, whereas CnKNOX2 expression was detected in tissues with and also in those without meristem.
TL;DR: Seeds of Medicago truncatula are a new, useful model for genetic and molecular studies which can complement those developed for Arabidopsis, and the endosperm is likely the main factor in the reduced germination of freshly harvested seeds.
Abstract: Seeds of Medicago truncatula, a genomic model species for legumes, exhibit physiological and physical dormancy. Here, the factors influencing the germination behaviour of freshly harvested and stored seeds were investigated using several genotypes. Hardseededness is promoted when mature seeds are equilibrated at relative humidities (RH) below 75%. The release of physical dormancy during imbibition was dependent on the initial water content/RH that the seeds were dried to: the drier the seeds, the longer the imbibition time needed to break physical dormancy. The kinetics of physical dormancy release was slower than that of physiological dormancy, making it possible to uncouple both phenomena. Freshly harvested embryos without seed coverings germinated at the same speed as afterripened seeds. The depth of dormancy varied between different M. truncatula genotypes, from more to less dormant: DZA315.16 > A17 (Jemalong) > R108 > DZA45.5. This difference was eliminated by removing the endosperm. Collectively, these observations indicate that the endosperm is likely the main factor in the reduced germination of freshly harvested seeds. White light decreased germination speed of dormant seeds whereas it had no effect on non-dormant seeds. Recently harvested seeds were most dormant at temperatures above 17 C, whereas afterripened seeds germinated over a wider range of temperature. Fluridone could efficiently break dormancy, reinforcing the role of abscisic acid (ABA) synthesis. However, dormancy was not affected by gibberellic acid (100 mu M GA(3)) or nitrate. The particular dormancy features unravelled here for M. truncatula, combined with the available genomic resources, make it a new, useful model for genetic and molecular studies which can complement those developed for Arabidopsis.
TL;DR: It was found that pollen germination for all cultivars were greatly reduced with increased GA 3 concentration in the germination medium and reached the lowest value at the 100 ppm GA 3 whereas germination was decreased up to 25 ppm in H 3 BO 3 and gradually increased again to 100 ppm.
Abstract: This study was conducted on male pistachio cultivars which consisted of Uygur, Atli, Kaska, Sengel and Kavak to study the influence of boron and gibberellin on pollen germination in vitro . Pollen was sown in germination media that included 20% sucrose, 10, 25, 50, 75 and 100 ppm boric acid (H 3 BO 3 ) and gibberellic acid (GA 3 ), separately. It was found that pollen germination for all cultivars were greatly reduced with increased GA 3 concentration in the germination medium and reached the lowest value at the 100 ppm GA 3 whereas germination was decreased up to 25 ppm in H 3 BO 3 and gradually increased again to 100 ppm. With the mediums of boric acid and gibberellic acid ranging from 0 - 100 ppm, the amount and pattern of response in pollen germinability varied among cultivars considerably. Pollen germination was severely inhibited by GA 3 and slightly promoted by boron. The results suggest that gibberellic acid had adverse effects on pollen germination of pistachio. Key words : Pistachio, Pistacia vera, in vitro, pollen germination, boron, gibberellic acid.
01 Jan 2010
TL;DR: In this paper, the effect of foliar application with benzyl adenine (BA) at (50, 100 and 150 ppm) and gibberellic acid (GA 3 ) at (100, 150 and 200 ppm) on the vegetative growth and some chemical constituents of croton plants was studied.
Abstract: A pot experiment was conducted during 2008 and 2009 seasons at National Research Centre, Dokki, Cairo, Egypt, Research and Production Station, Nubaria. The aim of this work is to study the effect of foliar application with benzyl adenine (BA) at (50, 100 and 150 ppm) and gibberellic acid (GA 3 ) at (100, 150 and 200 ppm) on the vegetative growth and some chemical constituents of croton plants. Most of the criteria of vegetative growth expressed as plant height, number of branches and leaves/plant, root length, leaf area and fresh and dry weights of stem, leaves and roots were significantly affected by application of the two factors which were used in this study.All foliar applications of BA and GA 3 separately promoted all the aforementioned characters in this study, as well as chemical constituents i.e. Chl. (a and b), carotenoids, total soluble sugars, total indoles ,total soluble phenols and N, P and K content compared with control plants. The highest recorded data were obtained in plants treated with GA 3 200 pm for all chemical constituents and growth parameters, except stem diameter and number of branches/plant, and N, P and K % while BA 150 ppm gave the highest stem diameter and number of branches and N, P and K % and content. (Journal of American Science 2010;6(7):126-130). (ISSN: 1545-1003).
TL;DR: Effect of light quality indicates evidence of phytochrome-mediated germination and dormancy in guayule and appears to act on the same pathway as light and GA 3.
TL;DR: All the tested strategies combining two measures have shown their potential to prolong the ripening period and therewith to improve wine quality and the combined use of gibberellic acid and leaf removal represents a sustainable strategy for integrated viticulture due to its reduced input of organic-synthetic pesticides into the environment.
Abstract: Aim: The present work evaluated different strategies for the control of grey mold, caused by Botrytis cinerea, on wine grapes, including the use of the plant growth regulator Gibb3, leaf removal and/or botryticide treatments. The efficiency of the different control strategies (disease incidence and severity, yield) as well as the effect on the cluster structure was investigated.Methods and results: The trials were conducted in commercial vineyards in the Moselle Valley (Luxembourg) between the years 2007 and 2009, on the Pinot gris, Pinot blanc and Pinot noir grape varieties. The untreated control (T1) was compared to the following treatments : (T2) Gibb3, (T3) Gibb3 combined with leaf removal in the cluster zone after bloom, (T4) leaf removal after bloom combined with two times botryticides and (T5) Gibb3 combined with two times botryticides. The combination of Gibb3 with leaf removal or botryticide applications led to an efficiency level in grey mold reduction of around 60% and a decrease in cluster density when compared to the control. Moreover, we showed that the progression of grey mold disease was slowed down by the three treatments T3, T4 and T5.Conclusions: Gibberellic acid applied at full bloom as stand-alone treatment did not reduce in a significant way the compactness of the grape clusters and the impact on grey mold development was low. For a significant decrease of disease severity, gibberellic acid had to be combined with an additional measure, such as leaf removal or the use of botryticides. Based on its positive effect on cluster structure and microclimate, leaf removal can be recommended as a basic measure that can be further combined with an application of botryticides or gibberellic acid.Significance and impact of the study: All the tested strategies combining two measures have shown their potential to prolong the ripening period and therewith to improve wine quality. Moreover, the combined use of gibberellic acid and leaf removal represents a sustainable strategy for integrated viticulture due to its reduced input of organic-synthetic pesticides into the environment.
TL;DR: An efficient protocol for in vitro organogenesis was achieved from callus-derived immature and mature leaf explants of Momordica charantia, a very important vegetable and medicinal plant, with an average of 40 plants per leaf explant with a culture period of 98 days.
Abstract: An efficient protocol for in vitro organogenesis was achieved from callus-derived immature and mature leaf explants of Momordica charantia, a very important vegetable and medicinal plant. Calluses were induced from immature leaf explants excised from in vitro (15-day-old seedlings) mature leaf explants of vivo plants (45 days old). The explants were grown on Murashige and Skoog (MS) medium with Gamborg (B5) vitamins containing 30 g l−1 sucrose, 2.2 g l−1 Gelrite, and 7.7 μM naphthalene acetic acid (NAA) with 2.2 μM thidiazuron (TDZ). Regeneration of adventitious shoots from callus (30–40 shoots per explant) was achieved on MS medium containing 5.5 μM TDZ, 2.2 μM NAA, and 3.3 μM silver nitrate (AgNO3). The shoots (1.0 cm length) were excised from callus and elongated in MS medium fortified with 3.5 μM gibberellic acid (GA3). The elongated shoots were rooted in MS medium supplemented with 4.0 μM indole 3-butyric acid (IBA). Rooted plants were acclimatized in the greenhouse and subsequently established in soil with a survival rate of 90%. This protocol yielded an average of 40 plants per leaf explant with a culture period of 98 days.
TL;DR: A protocol for micropropagation of Arbutus andrachne from seeds was developed, and results indicated that none of the seeds cultured on Murashige and Skoog medium, with or without plant growth regulators (PGRs), germinated.
Abstract: A protocol for micropropagation of Arbutus andrachne from seeds was developed. Results indicated that none of the seeds cultured on Murashige and Skoog (MS) medium, with or without plant growth regulators (PGRs), germinated. Seeds soaked in 250 mg l−1 gibberellic acid (GA3) at 4°C for 3 days, then cultured on water-agar medium containing 2.0 mg l−1 GA3 exhibited 80–100% germination and developed into usable seedlings. Shoot proliferation was tested on MS or B5 medium containing different concentrations of cytokinin. No shoot proliferation was observed on PGR-free medium. Proliferation was more successful on MS than on B5 medium. On both media, the most successful proliferation was obtained using zeatin as a cytokinin type. Rooting was tested on MS medium containing different concentrations of auxin. Rooting failed on PGR-free medium and on medium containing indole-3-acetic acid (IAA), 0.25 or 0.5 mg l−1 indole-3-butyric acid (IBA), or 0.25, 0.5 or 2.0 mg l−1 α-naphthaleneacetic acid (NAA). Rooting (40%) was most successful with 1.0 mg l−1 NAA. Rooted plantlets exhibited 80% survival in all mixtures of peatmoss and perlite, and acclimatized plants were successfully grown in the greenhouse. Quantitative analysis of arbutin performed on in vivo and in vitro leaves using high-performance liquid chromatography (HPLC) revealed that in vivo leaves contained higher arbutin content (0.3–0.81% w/w) than in vitro leaves (0.09% w/w). The highest yield of arbutin in vivo was detected in leaves collected in August, and the lowest yield in leaves collected in December.