Showing papers on "Gibberellic acid published in 2014"
TL;DR: Plant growth-promoting rhizobacteria (PGPR) treatments increased fresh and dry shoot and root weight, stem diameter, seedling height, chlorophyll reading values, and leaf area of cabbage seedlings compared with the control.
Abstract: A greenhouse experiment was conducted to observe the effects of Bacillus megaterium strain TV-91C, Pantoea agglomerans strain RK-92, and B. subtilis strain TV-17C inoculation on the growth, nutrient, and hormone content of cabbage seedlings. The seeds of cabbage were incubated in flasks by shaking at 80 rpm for 2 h at 28 °C to coat the seeds with the rhizobacteria. Plant growth-promoting rhizobacteria (PGPR) treatments increased fresh and dry shoot and root weight, stem diameter, seedling height, chlorophyll reading values, and leaf area of cabbage seedlings compared with the control. Among the strains, B. megaterium TV-91C gave the greatest seedling nutrient content and growth parameters, although the maximum values for leaf area, gibberellic acid, salicylic acid, and indole acetic acid (IAA) contents of seedlings were obtained with the P. agglomerans RK-92 treatment. Seed inoculation with B. megaterium TV-91C increased fresh and dry shoot and root weight by 32.9%, 22.6%, 16.0%, and 35.69%, respectively. Inoculations also increased the stem diameter, seedling height, and SPAD chlorophyll values by 47.5%, 27.2%, and 5.8%, respectively. Furthermore, compared to the control, P. agglomerans RK-92 increased gibberellic acid, salicylic acid, IAA, and leaf area by 13.9%, 70.9%, 38.5%, and 27.3%, respectively. PGPR treatments may improve seedling growth and quality in cabbages.
121 citations
TL;DR: Despite the preference for MGE, soaking seeds in either extract, prior to germination and growth under NaCl-salinity, increased the seed germination percentage, seedling growth, the cell membrane stability index, the relative water content, and the activity of the antioxidant system.
77 citations
Journal Article•
TL;DR: The results of this study showed that bacterial inoculations increased plant growth parameters and the use of bacteria treatments may provide a means of improving transplant growth and qual- ity in cauliflower.
Abstract: This study was conducted to determine the effect of different plant growth promoting rhizobacteria (PGPR) strains on growth and quality of cauliflower transplants under greenhouse conditions. The strains of Bacillus megaterium TV-3D, B. megaterium TV-91C, Pantoea agglomerans RK-92, B. subtilis TV-17C, B. megaterium TV-87A, B. megaterium KBA-10 were used in this study. The results of this study showed that dif- ferent bacterial inoculations increased plant growth parameters such as fresh shoot weight, dry shoot weight, root diameter, root length, fresh root weight, dry root weight, plant height, stem diameter, leaf area and chlorophyll contents of cauliflower transplant respec- tively. Except for abscisic acid (ABA), the values of gibberellic acid (GA), salicylic acid (SA), indole acetic acid (IAA) was increased by ratio of 23.64, 89.54 and 25.63%, respec- tively in compared to the control by application of B. megaterium KBA-10 and P. ag- glomerans RK-92. The amount of organic acids with B. subtilis TV-17C PGPR applica- tions have increased at a ranging ratio from 9.63 to 186.02%. Also, PGPR inoculations in- creased the macro and micro nutrient content of cauliflower transplants. As a result, the use of bacteria treatments may provide a means of improving transplant growth and qual- ity in cauliflower.
63 citations
TL;DR: It is concluded that GA3 applied at lower concentrations (25 mg L−1) renders greater beneficial effects on vase life quality, membrane stability and antioxidant activities in gladiolus cut spike, and further higher application rates cause no improvement in the flower longevity.
Abstract: Cut flowers face the problem of short display life and lose their aesthetic value rapidly. In order to enhance the vase life of gladiolus, its cut spikes were subjected to different levels of gibberellic acid (GA3), viz., 0, 25, 50, 100 and 200 mg L−1 in vase solution, during two consecutive years 2010 and 2011. The GA3 treatment significantly influenced the vase quality attributes and antioxidants capacity of gladiolus cut flowers. Gibberellic acid at 25 mg L−1 caused the longest time taken to open the floret and increased the floret opening, vase life duration and fresh weight. The highest antioxidative activities of superoxide dismutase and free radicals scavenging were also recorded with GA3 at 25 mg L−1. The highest peroxidase, catalase activity and the lowest membrane leakage were recorded with GA3 at 50 mg L−1. Present study concludes that GA3 applied at lower concentrations (25 mg L−1) renders greater beneficial effects on vase life quality, membrane stability and antioxidant activities in gladiolus cut spike, and further higher application rates cause no improvement in the flower longevity.
60 citations
TL;DR: The main objective of the present study was to establish feasible propagation methods for healthy biomass production and preferred micropropagation (85%) over seed germination (25.51-40%) and stem cutting (60%).
56 citations
TL;DR: A light requirement for germination, observed in virtually all taxa examined, constitutes a collective characteristic of the Campanulaceae family, and it is postulated that smaller seeded taxa might germinate only on the soil surface or at shallow depths, while larger seeded species might additionally germination when buried in the soil if cued to do so by fluctuating temperatures.
52 citations
TL;DR: It is suggested that MC application could reduce endogenous GA levels in cotton through controlled GA biosynthetic and metabolic genes expression, which might inhibit cell elongation, thereby shortening the internode and reducing plant height.
50 citations
TL;DR: Based on all growth and physiological data, Spd tended to be more effective than A3 in improving salt tolerance in both rice cultivars and Salt-stressed seedlings grown from seeds primed with these growth regulators also possessed higher phenolic contents and greater antioxidant capacity than the control seedlings.
Abstract: This study was carried out to elucidate the spermidine (Spd) and gibberellic acid (GA3) priming-induced physiological and biochemical changes responsible for induction of salinity tolerance in two rice (Oryza sativa L.) cultivars, namely ‘Niewdam Gs. no. 00621’ (salt tolerant) and ‘KKU-LLR-039’ (salt sensitive). The seeds of the two cultivars were primed separately with distilled water, 1 mM Spd or 0.43 mM GA3. Primed seeds were germinated and the resultant seedlings were hydroponically grown for 14 days before being exposed to salinity stress (150 mM NaCl) for 10 days. Seed priming with Spd or GA3 slightly improved salt-induced reductions in growth, anthocyanin and chlorophyll contents of the seedlings. Salt stress induced pronounced increases in Na+/K+ ratio, proline and H2O2 contents, particularly in the sensitive cultivar. The levels of these salt-sensitivity physiological indicators tended to be mitigated by priming with Spd and GA3. Salt-stressed seedlings grown from seeds primed with these growth regulators also possessed higher phenolic contents and greater antioxidant capacity than the control seedlings. Based on all growth and physiological data, Spd tended to be more effective than A3 in improving salt tolerance in both rice cultivars.
49 citations
TL;DR: In this article, a two-year study, girdling at berry set, gibberellic acid (10 mg/L), and forchlorfenuron (9.75 mg/l) were investigated to verify their effects on berry size, yield and chemical and metabolic characteristics of Italia grapes.
Abstract: Among the various vineyard treatments adopted in recent years for table-grape cultivation, there has been a significant use of plant growth regulators (PGRs) and girdling to increase berry size and yield. In particular, an increase in the application of forchlorfenuron (CPPU) and gibberellic acid (GA 3 ) for many seeded and seedless table-grape cultivars has been registered in several countries. In this two-year study, girdling at berry set, gibberellic acid (10 mg/L) applied at berry diameter of 10 to 11 mm, and forchlorfenuron (9.75 mg/L) applied at berry diameter of 11 to 12 mm were investigated to verify their effects on berry size, yield, and chemical and metabolic characteristics of Italia grapes. In general, at harvest all treatments significantly increased berry diameter, length, and weight and consequent cluster weight and yield/vine compared to an untreated control. The treatments showed significant differences for the colorimetric parameters, in particular a higher value of hue for berries treated with GA 3 and CPPU, thus shifting the skin color from yellow toward yellow-green. Metabolomic study carried out by nuclear magnetic resonance spectroscopy combined with principal component analysis indicated that metabolic profile depends on the year and, in each year, the effect of treatments consisted of a slight variation of amino acid content. Treatments effects were more pronounced in the year characterized by a cooler summer.
45 citations
TL;DR: Optimal priming treatment may be recommended as efficient tools to facilitate revegetation of former mining area and improved the light phase of photosynthesis and strengthened the antioxidant system of stressed seedlings.
Abstract: Seed priming effects on Trifolium repens were analysed both in Petri dishes and in two soils (one unpolluted soil and a soil polluted with Cd and Zn). Priming treatments were performed with gibberellic acid 0.1 mM at 22 °C during 12 h or with polyethylene glycol (−6.7 MPa) at 10 °C during 72 h. Both priming treatments increased the germination speed and the final germination percentages in the presence of 100 μM CdCl2 or 1 mM ZnSO4. Flow cytometry analysis demonstrated that the positive effect of priming was not related with any advancement of the cell cycle in embryos. Seed imbibition occurred faster for primed seeds than for control seeds. X-ray and electronic microscopy analysis suggested that circular depressions on the seed coat, in addition to tissue detachments inside the seed, could be linked to the higher rate of imbibition. Priming treatments had no significant impact on the behaviour of seedlings cultivated on nonpolluted soil while they improved seedling emergence and growth on polluted soil. The two priming treatments reduced Zn accumulation. Priming with gibberellic acid increased Cd accumulation by young seedlings while priming with polyethylene glycol reduced it. Priming improved the light phase of photosynthesis and strengthened the antioxidant system of stressed seedlings. Optimal priming treatment may thus be recommended as efficient tools to facilitate revegetation of former mining area.
43 citations
TL;DR: A simple and efficient regeneration protocol was established for soybean and Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants to investigate the effect of different plant growth regulators and polyamines on regeneration using direct organogenesis system.
Abstract: A simple and efficient regeneration protocol was established for soybean [Glycine max (L.) Merrill]. Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants. The effect of different plant growth regulators [N
6 –benzyladenine (BA), kinetin (KT), thidiazuron (TDZ), gibberellic acid (GA3), zeatin riboside (ZTR), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA)] along with polyamines (Spermidine, spermine, and putrescine) were investigated at different stages of regeneration using direct organogenesis system. Exogenous spermidine (137.69 μM) in shoot induction medium containing optimal BA concentration (2.22 μM) induced maximum number of shoots (39.02 shoots/explant) compared to BA (2.22 μM) alone. Regenerated shoots elongated well in shoot elongation medium containing GA3 (1.45 μM) and spermine (74.13 μM), and developed profuse roots in root induction medium containing putrescine (62.08 μM). Rooted plantlets were successfully hardened and acclimatized with a survival rate of 92 %. The amenability of the standardized protocol using cultivar PK 416 was tested on four more Indian soybean cultivars JS 90–41, Hara soy, Co1, and Co2 of which PK 416 was found to be the best responding cultivar, with a maximum of 96.94 % shoot induction.
TL;DR: It is hypothesized that insects have obtained the capability to induce galls via acquisition of the biosynthetic pathways to produce IAA and trans-zeatin family CKs through microbial symbiosis or lateral gene transfer.
Abstract: The mechanism of gall induction by insects has remained elusive. Previous studies have met with limited success in attempting to induce galls by injection or application of chemical compounds. To determine whether an exogenous source of phytohormones plays a role in gall induction, we injected cytokinin (CK), auxin (IAA), gibberellic acid (GA), and abscisic acid (ABA) in various concentrations, ratios, and combinations into leaf petioles of Capsicum annuum L. cv. California Wonder (Solanaceae). We found that CK + IAA injections lead to gall-like growth in C. annuum. GA enhanced and ABA inhibited gall growth except in the presence of GA. Isopentenyl adenine (IP) was the most effective type of CK at inducing growth. Our work is consistent with the hypothesis that exogenous CK + IAA produced and supplied by insects leads to gall induction. We hypothesize that insects have obtained the capability to induce galls via acquisition of the biosynthetic pathways to produce IAA and trans-zeatin family CKs through microbial symbiosis or lateral gene transfer.
Journal Article•
TL;DR: Gladiolus plants were sprayed thrice with different concentrations of gibberellic acid, benzylaminopurine and salicylic acid in order to improve the vegetative, floral and physiological attributes.
Abstract: Gladiolus is very popular among ornamental bulbous plants mainly used as cut flower and greatly demanded in the world floral market. Production of inferior quality spikes is one of the major hurdles for their export. The research was conducted under Faisalabad conditions to evaluate the use of plant growth regulators in order to improve the vegetative, floral and physiological attributes. Gladiolus plants were sprayed thrice with different concentrations (0.1, 0.4, 0.7 and 1mM) of gibberellic acid, benzylaminopurine and salicylic acid at three leaf stage, five leaf stage and slipping stage. Foliar application of 1mM gibberellic acid increased the plant height (122.14cm), spike length (58.41cm), florets spike -1 (13.49), corm diameter (4.43cm), corm weight (25.34g) and total cormel weight (20.45g) compared to benzylaminopurine and salicylic acid. Gibberellic acid at 1mM concentration also increased the total chlorophyll content to 7.72mg/g, total carotenoids (1.61mg/g), total soluble sugars (3.68mg/g) followed by application of benzylaminopurine. Salicylic acid application at 1mM concentration decreased the number of days to flower (64.93) compared to 76.12 days in non treated plants.
TL;DR: In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.
Abstract: The SUV3 (suppressor of Var 3) gene encodes a DNA and RNA helicase, which is localized in the mitochondria. Plant SUV3 has not yet been characterized in detail. However, the Arabidopsis ortholog of SUV3 (AT4G14790) has been shown to be involved in embryo sac development. Previously, we have reported that rice SUV3 functions as DNA and RNA helicase and provides salinity stress tolerance by maintaining photosynthesis and antioxidant machinery. Here, we report further analysis of the transgenic OsSUV3 rice plants under salt stress. The transgenic OsSUV3 overexpressing rice T1 lines showed significantly higher endogenous content of plant hormones viz., gibberellic acid (GA3), zeatin (Z) and indole-3-acetic acid (IAA) in leaf, stem and root as compared to wild-type (WT), vector control (VC) and antisense (AS) plants under salt (200 mM NaCl) stress condition. A similar trend of endogenous plant hormones profile was also reflected in the T2 generation of OsSUV3 transgenic rice under defined parameters and stress condition. In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.
TL;DR: It is concluded that the use of Dormex™, at a rate of 4 %, could be recommended for reaching bud break as early as possible and improving ‘Anna’ apple tree yield under the short winters in Egypt and similar regions by regulating the contents of proline, arginine and phytohormones in buds.
Abstract: A 2-season trial was conducted to verify the effects of foliar applications of some dormancy-breaking substances (DBS) on dormancy release in buds of ‘Anna’ apple (Malus sylvestris, Mill) trees, as well as on metabolic changes in the contents of phytohormones, proline and arginine in buds during their release from dormancy. The efficiency of early bud break induced by Dormex™, potassium nitrate, mineral oil, calcium nitrate and thiourea was noticed in varying degrees. Although Dormex™ was distinguished, all DBS hastened bud break, shortened flowering duration, improved bud break% and fruit-set%, increased the contents of gibberellic acid, indole-3-acetic acid, proline and arginine, but reduced abscisic acid content in buds as compared to the control. These results were positively reflected in the final tree yield. Accordingly, it is concluded that the use of Dormex™, at a rate of 4 %, could be recommended for reaching bud break as early as possible and improving ‘Anna’ apple tree yield under the short winters in Egypt and similar regions by regulating the contents of proline, arginine and phytohormones in buds.
TL;DR: The results showed a wide variation on yield, content and range of the molecule constituent of oil, with a balance of appearances and/or disappearances of a few molecules.
Abstract: Basil (O. gratissimum L) is a aromatic and medicinal plant widely used in traditional medicine in Morocco. The aim of this work was to study the effect of three plant growth regulators gibberellic acid (GA), indole 3-acetic acid (IAA) and benzylaminopurine (BAP) on the content and composition of essential oils of this plant, especially on the main compound (methyl chavicol) and its isomer (the trans-anethole). The results showed a wide variation on yield, content and range of the molecule constituent of oil, with a balance of appearances and/or disappearances of a few molecules. GA caused a slight decrease in the oil yield (0.2%), but it increased the diversity of compounds (17 molecules) with the appearance of four new compounds (naphthalene, camphor, germacrene-D, and ledene) and disappearance of (β cedrene, azulene). This variation also caused a very important decrease in the main compound (methyl chavicol) and increases its isomer (trans-anethole). IAA and BAP caused an increase in the yield of essential oil (0.30% and 0.32% respectively) without much influence on the main compounds, but with some change in the composition such as the appearance of (germacrene-D) and the disappearance of (aristolene).
TL;DR: Of the five ethylene receptor isoforms in Arabidopsis, ETR1 has a unique role in modulating the effects of red and far-red light on plant growth and development.
Abstract: When exposed to far-red light followed by darkness, wild-type Arabidopsis thaliana seeds fail to germinate or germinate very poorly. We have previously shown that the ethylene receptor ETR1 (ETHYLENE RESPONSE1) inhibits and ETR2 stimulates seed germination of Arabidopsis during salt stress. This function of ETR1 requires the full-length receptor. These roles are independent of ethylene levels and sensitivity and are mainly mediated by a change in abscisic acid (ABA) sensitivity. In the current study we find that etr1-6 and etr1-7 loss-of-function mutant seeds germinate better than wild-type seeds after illumination with far-red light or when germinated in the dark indicating an inhibitory role for ETR1. Surprisingly, this function of ETR1 does not require the receiver domain. No differences between these mutants and wild-type are seen when germination proceeds after treatment with white, blue, green, or red light. Loss of any of the other four ethylene receptor isoforms has no measurable effect on germination after far-red light treatment. An analysis of the transcript abundance for genes encoding ABA and gibberellic acid (GA) metabolic enzymes indicates that etr1-6 mutants may produce more GA and less ABA than wild-type seeds after illumination with far-red light which correlates with the better germination of the mutants. Epistasis analysis suggests that ETR1 may genetically interact with the phytochromes (phy), PHYA and PHYB to control germination and growth. This study shows that of the five ethylene receptor isoforms in Arabidopsis, ETR1 has a unique role in modulating the effects of red and far-red light on plant growth and development.
TL;DR: It is concluded that CbCBF confers cold resistance and growth inhibition to tobacco cells by interacting with gibberellin and cell cycle pathways, likely through activation of downstream target genes.
Abstract: Plant cells respond to cold stress via a regulatory mechanism leading to enhanced cold acclimation accompanied by growth retardation. The C-repeat binding factor (CBF) signaling pathway is essential for cold response of flowering plants. Our previously study documented a novel CBF-like gene from the cold-tolerant Capsella bursa-pastoris named CbCBF, which was responsive to chilling temperatures. Here, we show that CbCBF expression is obviously responsive to chilling, freezing, abscisic acid, gibberellic acid (GA), indoleacetic acid or methyl jasmonate treatments and that the CbCBF:GFP fusion protein was localized to the nucleus. In addition, CbCBF overexpression conferred to the cold-sensitive tobacco plants enhanced tolerance to chilling and freezing, as well as dwarfism and delayed flowering. The leaf cells of CbCBF overexpression tobacco lines attained smaller sizes and underwent delayed cell division with reduced expression of cyclin D genes. The dwarfism of CbCBF transformants can be partially restored by GA application. Consistently, CbCBF overexpression reduced the bioactive gibberellin contents and disturbed the expression of gibberellin metabolic genes in tobacco. Meanwhile, cold induced CbCBF expression and cold tolerance in C. bursa-pastoris are reduced by GA. We conclude that CbCBF confers cold resistance and growth inhibition to tobacco cells by interacting with gibberellin and cell cycle pathways, likely through activation of downstream target genes.
TL;DR: It is suggested that GA3 priming might increase the salt tolerance of alfalfa seedlings through enhancing the activities of antioxidant enzymes and reducing the membrane damage as estimated using biomarkers, EL index and MDA content.
Abstract: The experiment was conducted in order to study effects of seeds priming with gibberellic acid (GA3) at 0, 3, 5 and 8 mM on germination, growth and antioxidant enzymes activity in alfalfa seedlings under salinity stress (200 mM NaCl). All control seeds germinated. The rate of germinated seeds was reduced to 48% in the presence of NaCl, and increased to 76% after seeds priming with 5 mM GA3. Priming with 5 mM GA3 was also correlated with an increase of dry weight of seedlings derived from both stressed and non-stressed seeds as well as with the reduction of electrolyte leakage (EL) and malondialdehyde (MDA) level in salt stressed seedlings. The activity of superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase in primed and non-primed seeds increased in the presence of NaCl and after priming of seeds with 5 mM GA3, whereas only small effect on glutathione reductase activity in both primed and non-primed seeds was observed. The total ascorbate level was higher in both stressed and non-stressed seedlings from primed seeds. These results suggest that GA3 priming might increase the salt tolerance of alfalfa seedlings through enhancing the activities of antioxidant enzymes and reducing the membrane damage as estimated using biomarkers, EL index and MDA content.
TL;DR: Phytohormone immunolocalization analysis suggested that IAA involved in differentiation and development of each floral organs, GA and zeatin play important roles in floret primordia differentiation and ovule development and IAA signaling is involved in the pedicel and corolla elongation and delay flowering slightly.
TL;DR: The effect of gibberellic acid on growth, fruit yield and quality of tomato was determined and ascorbic acid, total soluble solid (TSS) was estimated for GA3 50 ppm.
Abstract: This study was conducted with the objective to determine the effects of Gibberellic acid (GA3) on growth, fruit yield and quality of tomato. The experiment consisted of one tomato variety- Golden, and six treatments with five levels of gibberellic acid (GA3- 10 ppm, 20 ppm, 30 ppm, 40 ppm and 50 ppm), arranged in randomized block design with three replications. The highest plant height, Number of leaves, Number of fruits, Fresh fruit weight has been observed and ascorbic acid, total soluble solid (TSS) was estimated for GA3 50 ppm. I. Introduction Tomato (Lycopersicon esculentum Mill.) belongs to family solanaceae having chromosome number (2n=24). It is a self pollinated crop and Peru-Ecuador region is considered to be the centre of origin. Tomato was introduced by the Portuguese. Tomato is cultivated in tropics and subtropics of the world. Tomato is one of the most highly praised vegetables consumed widely and it is a major source of vitamins and minerals. It is one of the most popular salad vegetables and is taken with great relish. Tomato has a significant role inhuman nutrition because of its rich source of lycopene, minerals and vitamins such as ascorbic acid and s-carotene which are anti-oxidants and promote good health. Plant growth regulators (PGRs) are extensively used in horticultural crops to enhance plant growth and improve yield by increasing fruit number, fruit set and size. Plant growth regulators like promoters, inhibitors or retardants play a key role in controlling internal mechanisms of plant growth by interacting with key metabolic processes such as, nucleic acid metabolism and protein synthesis. Use of plant growth regulators (PGR's) might be a useful alternative to increase crop production. Recently, there has been global realization of the important role of PGR's in increasing crop yield. GAs constitute a group of plant hormones that control developmental processes such as germination, shoot elongation, tuber formation, flowering, and fruit set and growth in diverse species. The most widely available plant growth regulator is GA3 or gibberellic acid, which induces stem and internode elongation, seed germination, enzyme production during germination and fruit setting and growth (Davies, 1995). Gibberellic acid is an important growth regulator that may have many uses to modify the growth, yield and yield contributing characters of plant (Rafeekher et al., 2002). Keeping these things, the present investigations to find out the effect of gibberellic acid on growth quality and yield of tomato. II. Materials And Methods This study was conducted at Central research field of SHIATS, Allahabad (U.P.). The experiment consisted of one tomato variety- Golden, five levels of gibberellic acid (GA3- 10 ppm, 20 ppm, 30 ppm, 40 ppm and 50 ppm arranged in randomized block design with three replications and six treatments (T0- Control, T1- 10 ppm GA3, T2- 20 ppm GA3, T3- 30 ppm GA3, T4- 40 ppm GA3, T5- 50 ppm GA3. The required weight of the PGRs was taken using electronic sensitive balance and solution was prepared by dissolving in 1 mg L -1 . The solution was poured into hand-held sprayer and was directly sprayed on the plants three times at 20, 40 and 60 days after transplanting. Spraying was performed early in the morning to avoid rapid drying of the spray solution, due to transpiration. All the recommended cultural practices were followed during the conduction of the experiment. Data were collected from selected plants in the rows. The collected data includes average plant height (cm), average number of leaves, average number of fruits, average fresh fruit weight (kg), ascorbic acid (mg/100g), total soluble solids (°Brix). The data was analyzed using analysis of variance (ANOVA) and mean separation was carried out at 5% probability level. III. Results And Discussion Plant height (cm)
TL;DR: The data showed that down-regulation of PSY resulted in alterations of gene expression in enzymes involved in many metabolic pathways, such as carotenoid, gibberellic acid, abscisic acid and chlorophyll biosynthetic pathway as well as causes predominant defects in plant growth and development.
Abstract: Phytoene synthase (PSY) is the first rate-limiting regulatory enzyme in the carotenoid biosynthesis pathway. In order to modify the floral color pattern by reducing carotenoid contents, a phytoene synthase-RNAi construct was delivered into protocorm-like body (PLB) of Oncidium hybrid orchid. The transgenic orchids show down-regulated level of PSY and geranyl synthase gene. They displayed semi-dwarf phenotype and brilliant green leaves. The microscopic anatomy revealed development-arrested plastids with rare grana. The total carotenoid content was decreased and the efficiency of the photosynthetic electron transport was declined. The chlorophyll level and the expression of chlorophyll biosynthetic genes, such as OgGLUTR and OgCS were dramatically reduced. HPLC analysis showed that the endogenous level of gibberellic acid and abscisic acid in the dwarf transformants are 4-fold lower than in wild type plants. In addition, chilling tolerance of the transgenic Oncidium plants was reduced. The data showed that down-regulation of PSY resulted in alterations of gene expression in enzymes involved in many metabolic pathways, such as carotenoid, gibberellic acid, abscisic acid and chlorophyll biosynthetic pathway as well as causes predominant defects in plant growth and development.
Journal Article•
TL;DR: In this paper, the effect of 2 levels of gibberellic acid (10 -4 and 10 -8 ) and two levels of potassium nitrate (6 and 8 mM) spray on the growth, leaf-NPK content, yield and quality parameters of tomato was investigated.
Abstract: A study was carried out to investigate the effect of 2 levels of gibberellic acid (10 -4 and 10 -8 ) and 2 levels of potassium nitrate (6 and 8 mM) spray on the growth, leaf-NPK content, yield and quality parameters of tomato. The application of gibberellic acid and potassium alone or in combination increased plant height, number of branches, number flowers per cluster, number fruits per cluster and faster fruit growth in addition to increasing fruit number, fruit firmness, weight and yield. The chlorophyll content, leaf- NPK content, blossom end rot and nitrate reductase activity were not affected by application of GA3 alone or in combination, but K application alone significant decreased blossom end rot while increasing leaf-NPK content, chlorophyll content and nitrate reductase activity. With regard to fruit quality, the application of GA3 at 10 -8 mM, 8 mM potassium nitrate and 10 -8 mM GA3+ 8 mM potassium nitrate increased fruit lycopene content, total soluble solids, vitamin C and titratable acidity compared with the control treatment. From this study, it can be concluded that spraying with gibberellic acid and potassium alone or in combination increased vegetative growth and reproductive characteristics of tomato.
TL;DR: The biochemical analysis indicated that the reduction of soluble protein and sugar, decrease in activity of polyphenol oxidase and peroxidase and accumulation of free amino acids in the lettuce leaves during storage could be remarkably prevented by low temperature, treatment with 1-MCP or GA.
Abstract: This study was conducted to evaluate the changes in quality of iceberg lettuce during storage at different temperatures and the effects of postharvest treatments of 1-methylcyclopropene or gibberellic acid at high temperature. The results showed that quality of the lettuce was remarkably retained during storage at 0 °C, but significantly declined at 20 °C. However, quality of the vegetable at shelf-temperature (20 °C, 85 ~ 95% RH) was effectively delayed by the treatment with 1-methylcyclopropene (1-MCP) or gibberellic acid (GA). Browning of the lettuce leaves was significantly inhibited by the storage at low temperature and by treatment with1-MCP and GA. The biochemical analysis further indicated that the reduction of soluble protein and sugar, decrease in activity of polyphenol oxidase (PPO) and peroxidase (POD) and accumulation of free amino acids in the lettuce leaves during storage could be remarkably prevented by low temperature, treatment with1-MCP or GA. Our result suggested that 1-MCP or GA treatment would provide a potential way for controlling quality of the lettuce under suboptimal postharvest temperature conditions.
TL;DR: An efficient plant regeneration system for mass multiplication through somatic embryogenesis was developed and can be widely used for mass propagation, transgenic recovery, and podophyllotoxin production for commercial utilization.
Abstract: Podophyllum hexandrum Royle known as Indian mayapple is an important medicinal plant found only in higher altitudes (2,700 to 4,200 m) of the Himalayas. The highly valued anticancer drug Podophyllotoxin is obtained from the roots of this plant. Due to over exploitation, this endemic plant species is on the verge of extinction. In vitro culture for efficient regeneration and the production of podophyllotoxin is an important research priority for this plant. Hence, in the present study, an efficient plant regeneration system for mass multiplication through somatic embryogenesis was developed. We have screened P. hexandrum seeds collected from three different regions in the Himalayas to find their regenerative potentials. These variants showed variation in germination percentage as well as somatic embryogenic frequency. The seeds collected from the Milam area of Pithoragarh district showed better germination response (99.3%) on Murashige and Skoog (MS) medium fortified with Gibberellic acid (GA3 [5 mg/l]) and higher direct somatic embryogenic frequency (89.6%). Maximum production of embryogenic callus (1.2 g fresh weight [FW]) was obtained when cotyledons containing the direct somatic embryo clusters were cultured in MS medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D [1.5 mg/l]) after 4 week of culture in complete darkness. In the present investigation, somatic embryogenesis was accomplished either by direct organogenesis or callus mediated pathways. The latter method resulted in a higher frequency of somatic embryo induction in hormone-free MS medium yielding 47.7 embryos/50 mg of embryogenic callus and subsequent germination in MS medium supplemented with GA3 (5 mg/l). Seventy-nine percent of embryos attained complete maturity and germinated into normal plants with well-developed roots. Systematic histological analysis revealed the origin of somatic embryo and their ontogenesis. The higher level of podophyllotoxin (1.8 mg/g dry weight [DW]) was recorded in germinated somatic embryos when compared to field grown plants. The present system can be widely used for mass propagation, transgenic recovery, and podophyllotoxin production for commercial utilization.
29 May 2014
TL;DR: The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth.
Abstract: In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana . Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans -zeatin riboside and dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis ( AtAAO , AtNIT and AtIPT ) revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli.
TL;DR: Three different Fusarium culmorum strains having a pathogenic, a deleterious (deleterious rhizosphere microorganism), or a promoting effect on plant growth were studied for their ability to synthesize in vitro the phytohormones indoleacetic acid (IAA), gibberellic acid (GA), and ethylene.
Abstract: Three different Fusarium culmorum strains having a pathogenic, a deleterious (deleterious rhizosphere microorganism), or a promoting (plant growth promoting fungus) effect on plant growth were studied for their ability to synthesize in vitro the phytohormones indoleacetic acid (IAA), gibberellic acid (GA), and ethylene. All the phytohormones tested were synthesized in cultures supplemented with wide concentration ranges of glucose and tryptophan or methionine (precursors of phytohormone synthesis). The amounts of these secondary metabolites synthesized by the particular strains were found to be significantly different. The non-pathogenic PGPF strain (DEMFc2) synthesized the highest amounts of IAA and GA, a fact that could be responsible for the growth-promoting properties of this strain. A pathogenic strain synthesized the highest amount of ethylene, which could be responsible for the negative effect of this strain on plant growth. F. culmorum isolates with a high capacity for IAA synthesis also have a high capacity for GA synthesis and irrespective of the growth conditions, a high positive correlation (R > 0.9) between the concentrations of synthesized IAA and GA in F. culmorum cultures was found. It is worth mentioning that the optimal conditions for the growth of F. culmorum isolates and the synthesis of the individual phytohormones differed from one another. The optimal growth conditions were 1.0% of glucose and 9.9 mM of methionine or 6.0 mM of tryptophan. The optimal conditions for ethylene synthesis were 0.5% of glucose and 6.6 mM of methionine, whereas 1.0% of glucose and 9.0 mM of tryptophan were optimal for IAA and GA synthesis.
TL;DR: In this article, the effects of plant growth-promoting substances (PGPSs) on biochemical changes occurring during seed germination of Phaseolus vulgaris were assessed. And the results indicated that PGPSs may act via stress-relieving biochemical pathways during seed growth.
Abstract: Smoke-water (SW), karrikinolide (KAR 1 ) and vermicompost leachate (VCL) have been reported to possess gibberellic acid-like activity. The effects of these plant growth-promoting substances (PGPSs) on biochemical changes occurring during seed germination of Phaseolus vulgaris were assessed. Seeds were incubated/germinated under dark conditions in water (control) or with different concentrations of SW, KAR 1 , VCL and gibberellic acid (GA 3 ) for 7 d. The maximum seedling fresh weight (1.863 g) was recorded for the SW (1:750 v/v) treatment. The longest seedling axes (9.9 cm) and the highest number of adventitious roots (16.3) were recorded for VCL-treated seedlings (1:10 and 1:5 v/v, respectively). Analysis of two important hydrolytic enzymes, acid phosphatase and alpha-amylase, showed maximum activity [1856 nkat mg − 1 and 3.225 mg min − 1 (g FW) − 1 , respectively] in the seeds incubated with 10 − 8 M KAR 1 . In all the treated seedlings, proline content was significantly reduced [43.67 μg (g FW) − 1 ; VCL (1:20 v/v)] in comparison to the control [87 μg (g FW) − 1 ] but there was an increase in amino acids with some concentrations of PGPSs. The tested PGPSs significantly influenced various biochemical parameters that play a significant role in seed germination and plant growth. This study indicates that PGPSs may act via stress-relieving biochemical pathways during seed germination.
TL;DR: In a series of laboratory and greenhouse experiments, the effects that treatment with gibberellic acid (GA3) and potassium nitrate (KNO3), as well as environmental factors, including temperature, the duration of pre-chilling (wet and dry), drought stress, salt stress, pH, and sowing depth, have on seed dormancy breaking and germination in C. bursa-pastoris as discussed by the authors.
Abstract: Shepherd's purse (Capsella bursa-pastoris) is a problematic weed in citrus orchards and crop fields in northern Iran. In a series of laboratory and greenhouse experiments, we evaluated the effects that treatment with gibberellic acid (GA3) and potassium nitrate (KNO3), as well as environmental factors, including temperature, the duration of pre-chilling (wet and dry), drought stress, salt stress, pH, and sowing depth, have on seed dormancy breaking and germination in C. bursa-pastoris. Treatment with GA3 strongly stimulated germination of C. bursa-pastoris in conditions of light/dark and continuous darkness. The germination rate was highest (40.08%) for seeds treated with 400 ppm of GA3 in the light/dark condition. Treatment with KNO3 did not significantly influence seed germination. Longer wet pre-chilling promoted germination and was more successful in seed dormancy breaking than was dry pre-chilling. Seed germination occurred at 10-30oC and within a range of pH of 3-11. Drought and salt stress both strongly inhibited germination. Seedling emergence decreased in proportion to sowing depth. The rates of C. bursa-pastoris germination and seedling emergence were highest for seeds on the soil surface.
TL;DR: Interference with GA signaling is investigated by using molecular techniques as an alternative approach and generates transgenic petunia plants in which the gai mutant protein is over-expressed under the control of a dexamethasone-inducible promoter.
Abstract: Since stem elongation is a gibberellic acid (GA) response, GA inhibitors are commonly used to control plant height in the production of potted ornamentals and bedding plants. In this study, we investigated interfering with GA signaling by using molecular techniques as an alternative approach. We isolated three putative GID1 genes (PhGID1A, PhGID1B and PhGID1C) encoding GA receptors from petunia. Virus-induced gene silencing (VIGS) of these genes results in stunted growth, dark-green leaves and late-flowering. We also isolated the gai mutant gene (gai-1) from Arabidopsis. We have generated transgenic petunia plants in which the gai mutant protein is over-expressed under the control of a dexamethasone-inducible promoter. This system permits induction of the dominant Arabidopsis gai mutant gene at a desired stage of plant development in petunia plants by the application of dexamethasone (Dex). The induction of gai in Dex-treated T1 petunia seedlings caused dramatic growth retardation with short internodes.