Gibberellic Acid

The effect of isoprenoid growth regulators on avocado (Persea americana Mill. cv Hass) fruit growth and mesocarp 3-hydroxy-3- methylglutaryl coenzyme A reductase (HMCR) activity was inves- tigated during the course of fruit ontogeny. Both normal and small- fruit phenotypes were used to probe the interaction between the end products of isoprenoid biosynthesis and the activity of HMCR in the metabolic

A characteristic feature of biological responses to low-dose γ-irradiation is the absence of the direct dependency of the values of the effects induced by this factor on the dose quantity. In the work presented we attempted to denote the key dose levels for γirradiation in  up to 1 Gy range within which the genetic responses of Tradescantia (clon 02) test systems “pink somatic mutations” differ qualitatively from each other.

Pathogenesis-related (PR) proteins are plant proteins that are induced in response to pathogen attack. PR proteins are grouped into independent families based on their sequences and properties. The PR-4 family comprises class I and class II chitinases. We have isolated a full-length cDNA encoding a chitinase from maize which shares a high degree of nucleotide and amino acid sequence homology with the class II chitinases of the PR-4 family of PR proteins. Our results indicate that fungal infection, and treatment either with fungal elicitors or with moniliformin, a mycotoxin produced by the fungus Fusarium moniliforme, increase the level of ZmPR4 mRNA. In situ mRNA hybridization analysis in sections obtained from fungus-infected germinating embryos revealed that ZmPR4 mRNA accumulation occurs in those cell types that first establish contact with the pathogen. ZmPR4 mRNA accumulation is also stimulated by treatment with silver nitrate whereas the application of the hormones gibberellic acid or acetylsalicylic acid has no effect. Wounding, or treatment with abscisic acid or methyl jasmonate, results in accumulation of ZmPR4 mRNA in maize leaves. Furthermore, the ZmPR4 protein was expressed in Escherichia coli, purified and used to obtain polyclonal antibodies that specifically recognized ZmPR4 in protein extracts from fungus-infected embryos. Accumulation of ZmPR4 mRNA in fungus-infected maize tissues was accompanied by a significant accumulation of the corresponding protein. The possible implications of these findings as part of the general defence response of maize plants against pathogens are discussed.

Plant growth substances are well-known to improve the source-sink connection and encourage the translocation of photo-assimilates thereby helping in effective flower formation, fruit and seed development and ultimately increase the yield of crops. A pot experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during November, 2013 to March, 2014 in a Randomized Complete Block Design (RCBD) based on five replications with a view to find out the influence of different plant growth regulators and their stages of application on the growth and yield of soybean cv. BARI Soybean-6. Application of plant growth regulators at different stages of plant showed significant effect on plant height, number of branches/plant , chlorophyll content (SPAD value), average length of internode, dry weight/plant and seed yield of soybean. Results showed that application of GA3 at vegetative stage produced the tallest plant (61.16 cm) and longest average length of internode (8.79 cm) and spray at flower initiation stage provided maximum SPAD value (50.38). Kinetin at vegetative stage gave the highest dry weight (23.68 g/plant) of soybean. Results also revealed that salicylic acid applied at flower and pod initiation stage gave the highest number of branches/plant (11.00) and seed yield (6.38 g/plant), compared to other growth regulators. So salicylic acid acts an important role for increasing soybean yield, when it was applied at flower and pod initiation stage.

An experiment was conducted at experimental field of Sher-e-Bangla Agricultural University, Bangladesh to find out the growth and yield performance of wheat to gibberellic acid concentrations. Experiment consisted foliar application of three concentrations of GA3 viz. G0: No GA3 i.e., control condition; G1: 100 ppm GA3 and G2: 200 ppm GA3. Maximum plant height (89.9 cm), number of tiller/plant (5.0), CGR (5.8), RGR (0.04), dry matter content/plant (26.8 g), number of spikes/plant (4.1), number of spikelets/spike (19.0), ear length (17.0 cm), filled grains/spike (30.4), total grains/spike (32.6), weight of 1000-grains (45.5 g), grain yield (3.9 tha-1), straw yield (4.6 tha-1), biological yield (8.5 tha-1) and harvest index (46.1%) were found from G2 whereas minimum from G0.

Conditions for induction of androgenesis in coconut cv. Sri Lanka Tall were studied. Anthers collected from inflorescences at four maturity stages were given heat (38°C) or cold (4°C) pretreatments for 1, 3, 6 and 14 days, either prior to or post inoculation. Three different basal media and different anther densities were also tested. Androgenesis was observed only in anthers collected from inflorescences 3 weeks before splitting (WBS) and after a heat pretreatment at 38°C for 6 days. Modified Eeuwens Y3 liquid medium supplemented with 100 μM 2,4-dichlorophenoxyacetic acid (2,4-d), 0.1% activated charcoal and 9% sucrose was effective in inducing an androgenic response. The lowest anther density tested, 10 per petri plate, was found to be the optimal density. When androgenic calli or embryos were subcultured to Y3 medium containing 66 μM 2,4-d, followed by transfer to Y3 medium without plant growth regulators and finally to Y3 medium containing 5 μM 6-benzyladenine (BA) and 0.35 μM gibberellic acid (GA3), plantlets regenerated at a frequency of 7%. Histological study indicated that the calli and embryos originated from the inner tissues of the anthers. Ploidy analysis of calli and embryos showed that they were haploid. This is the first report of successful androgenesis yielding haploid plants from coconut anthers.

Picrorhiza kurrooa Royle ex Benth., a high value medicinal herb of alpine Himalaya and a source of hepatoprotective picrosides, is listed as ‘endangered’ due to heavy collection from its natural habitat. The present report deals with successful propagation of this species using both conventional and in vitro techniques. Vegetative propagation was achieved by rooting runner cuttings with indole-3-butyric acid (IBA) or α-naphtheleneacetic acid (NAA) treatment before planting. Nearly 87% rooting success was achieved by treatment of cuttings with 50.0 μM IBA. Seeds were given a presoaking treatment with gibberellic acid (GA3), 6-benzylaminopurine (BAP) or a combination of both to influence germination. More than 11-fold improvement in germination was recorded in seeds treated with 250.0 μM GA3. In vitro shoot multiplication was achieved through sprouting of axillary buds using nodal segment. Multiple shoots were formed following culture for 3 weeks on Murashige and Skoog (MS; 1962. Physiologia Plantarum 15: 473–497) medium containing 1.0 μM BAP. Cent percent rooting success, without basal callus formation, was observed when individual microshoots were placed in MS medium supplemented with IBA. The plantlets raised using conventional as well as tissue culture methods were hardened and successfully established in the experimental field located at 2450 m elevation. In addition, strategies have been discussed to encourage cultivation and in situ conservation of this highly valued medicinal herb so as to reduce pressure on its natural populations.

A complete protocol is presented for the first time for the micropropagation of Pongamia pinnata, a biofuel tree, using cotyledonary nodes derived from axenic seedlings. Multiple shoots were induced in vitro from nodal segments through forced axillary branching. Murashige and Skoog (MS) medium supplemented with 7.5 μM benzylaminopurine (BAP) induced up to 6.8 shoots per node with an average shoot length of 0.67 cm in 12 d. Incorporation of 2.5 μM gibberellic acid (GA3) in the medium during the first subculture after establishment and initiation of shoot buds significantly improved the shoot elongation. Single use of GA3 during the first subculture eliminated the need for prolonged culturing on BAP medium. Further use of GA3 in the medium was not useful. Shoot culture was established for at least two subcultures without loss of vigor by repeatedly subculturing the original cotyledonary node on shoot multiplication medium followed by shoot elongation medium after each harvest of the newly formed shoots. Thus, from a single cotyledonary node, about 16–18 shoots were obtained in 60 d. Shoots formed in vitro were rooted on full-strength MS medium supplemented with 1.0 μM indole butyric acid (IBA). Plantlets were successfully acclimated, established in soil, and transferred to the nursery.

A field experiment was undertaken to evaluate the efficiency of Boron and Gibberellic Acid (GA3) on fruit setting phenomenon in
Olive cultivar Gemlik at the Experimental area in Olive fruit orchard at NARC, HRI during 2010-2011. The Olive plants were sprayed
with 3 concentrations of Boron i.e. 0.03, 0.06 and 0.09 % and GA3 in 3 concentrations i.e. 20, 25 and 30 ppm after flowering opening.
The results showed that maximum flowering (No. 789) with the application of Boron treatment @ 0.09%, while GA3 maximum
flowering (No. 422) with 30 ppm treatment. Maximum percent fruit setting (26.5) was recorded with GA3 spray @ 30ppm, and it was
followed by the application of GA3 @ 25ppm (21.25) and maximum fruit setting (13.07) was observed with Boron treatment and @
0.09%. Maximum fruit setting on the basis of total number of flowers was also observed in the application of GA3 treatment @ 30ppm
(7.53%). Maximum number of fruits, fruit size and fruit yield observed with 30ppm GA3 was 75.00, 3.569cm and 3.425 kg,
respectively and maximum fruits, fruit size and fruit weight was recorded with Boron treatment @ 0.09% was 65.30, 3.372 cm and
3.342 kg, respectively. It may be concluded that application of Boron @ 0.09% and GA3 @ 30ppm was optimum for the maximization
in number of flowers, fruit set, fruit size and even fruit weight in Olive cv “Gemlik”

Different concentrations of GA3 (15ppm, 20ppm and 25ppm) were applied to grape CV. Perlet as Bloom treatments in 2011, in two
splits doses. The first spray was applied at 70-80% bloom (on 4th April) and followed by second spray as the post bloom treatment,
just after fruit setting (on 8th May). Three vines were used for each treatment. After the fruits were fully mature, five clusters were
randomly harvested from each vine to determine the cluster and berry eight, number of berries per cluster, berry length and width, 100
berry weight, fruit weight and fruit extract content was measured using hand refractometer and determining the percentage content of
extract in the juice solution, squeezing the out of 20 representative berries from each plant. Average cluster and berry weight of
sprayed vines increased significantly over the non-sprayed vines and the largest cluster weight depicted as fruit yield as per vine
(10.7kg) was found in the treatment with highest concentration of GA3 (25ppm). Maximum berry weight, length berry width and TSS
were 2.83 g, 1.86 cm, 1.81 g and 19.22%, respectively recorded at 25pp. More over Statistical differences were observed for cluster
weight, berry width, length and total soluble salts with GA3 at 15ppm and 20ppm.GA3 at 25ppm may be recommended for spray on the
perlet grape cultivar for obtaining higher yield and better quality/fruits.

SUMMARY Fruit size can be improved either by increasing carbohydrates availability to fruit or by increasing fruit sink strength. Application of synthetic auxins may act in these two ways, depending on the date of treatment. When they are applied during the physiological drop they have a thinning effect, reducing competition for carbohydrates among developing fruitlets; when applied at the onset

The aim of this study was to determine the effects of gibberellic acid (GA3) on some yield and quality components of safflower (Carthamus tinctorius L.). Research was conducted at Applying Research Field, Faculty of Agriculture, Namik Kemal University in 2014 and 2015. The experiment was laid out as a split plot design based on Randomized Complete Block Design with three replications, in which cultivars constituted the main plot with two cultivars (Dinçer and Balcı), and gibberellic acid constituted the sub-plot with four doses (control, 0 ppm, 100 ppm, 200 ppm and 300 ppm). Results showed that variation in doses of gibberellic acid had a significant effect on seeds per capsule, capsule diameter, 1000 seed weight, hull ratio, seed yield and oil ratio of safflower. Although GA3 applications significantly decreased the seed yield, increasing doses of GA3 increased the oil ratio and 1000 seed weight.

Coconut is a cross pollinating palm, propagated only by seeds. Tissue culture is the only vegetative propagation method available for coconut. Consistent callogenesis was obtained by culturing unfertilised ovaries at -4 stage in CRI 72 medium containing 100 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.1% activated charcoal. Callusing was improved by application of 9 μM thidiazuron (TDZ). Embryogenic calli were subcultured onto somatic embryogenesis induction medium containing 66 μM 2,4-D. Stunted growth was observed in the somatic embryos after subculture onto CRI 72 medium containing abscisic acid (ABA). Maturation of somatic embryos could be achieved in Y3 medium without growth regulators. Conversion of somatic embryos was induced by adding gibberellic acid (GA3) to conversion medium containing 5 μM 6-benzyladenine (BA) while 2-isopentyl adenine (2iP) increased the frequency of plant regeneration. A total of 83 plantlets was produced from 32 cultured ovaries.

Effect of GA3 on postharvest ripening in strawberry fruit was evaluated through different biochemical parameters. Strawberry slices at different ripening stages were incubated with GA3. A significant decrease on respiratory activity depending on GA3 concentration was obtained. Also GA3 was applied to whole and deachened fruit at white and green ripening stages. Our results show that GA3 has an inhibitory effect on strawberry fruit ripening, evidenced by a decrease in the respiratory activity and a delay in anthocyanin synthesis and chlorophylls degradation.

This study is carried out to study the effect of Gibberellic acid (GA3) and Titanium Dioxide Nanoparticles (Nano- TiO2) on some characteristics of medicinal plant of Ocimum basilicum Lamiaceae) under drought stress. The experiment was conducted as a factorial arrangement in randomized complete block design with four replications in which A, B, C are the three factors and factor A is related to the irrigation content as fc 100%, fc 70% and fc 40% and factor B in three levels with GA3 application with concentrations of 0 (control), 250 ppm, 500 ppm and factor C with three doses of titanium nanoparticles with concentrations of 0%, 0.01% and 0.03%. The results showed that the drought stress caused to decreasing of plant biomass and the foliar relative water content, and
the increasing of catalase and the level of anthocyanin in the medicinal plant of basil, while, the application of gibberellin and titanium nanoparticles caused to improving of the negative effects of the stress.The results of the study indicated that the drought stress causes to decreasing of quantitative and qualitative characteristics of the plant. The best treatments were recognized as follows: in 100% irrigation regime, non-application of gibberellin and application of Nano-TiO2 with concentration of 0.01%; in 70% irrigation regime, the application of gibberellin with concentration of 250 ppm and Nano-TiO2 with concentration of 0.03%; and in 40% irrigation
regime, the application of gibberellin with concentration of 500 ppm and Nano-TiO2 with concentration of 0.03%.

The effect of growth regulators on induction of androgenesis in coconut was investigated using seven different growth regulators at various concentrations and combinations. Three auxins (1-naphthalene acetic acid—NAA, indoleacetic acid—IAA, picloram) and three cytokinins (2-isopentyl adenine-2-iP, kinetin, zeatin) were tested either alone or in combination with 2,4-dichlorophenoxyacetic acid (2,4-D), using modified Eeuwens Y3 liquid medium as the basal medium. Among the tested auxins, 100 μM NAA in combination with 100 μM 2,4-D enhanced the production of calli/embryos (123) whereas IAA and picloram showed negative and detrimental effects, respectively, for androgenesis induction over 100 μM 2,4-D alone. Kinetin and 2-iP enhanced the production of calli/embryos when 100 μM 2,4-D was present in the culture medium. Both cytokinins at 10 μM yielded the highest frequencies of embryos (113 and 93, respectively) whereas zeatin (1 or 2.5 μM) had no impact on microspore embryogenesis. When calli/embryos (produced from different treatments in different experiments) were sub-cultured in somatic embryo induction medium (Y3 medium containing 66 μM 2,4-D), followed by maturation medium (Y3 medium without growth regulators) and germination medium (Y3 medium containing 5 μM-6-benzyladenine—BA and 0.35 μM gibberellic acid—GA3), plantlets were regenerated at low frequencies (in most treatments ranging from 0% to 7%).

With the aim of reducing the cost and time needed to treat yam tubers with gibberellic acid (GA3), this study compared several new methods of application with the established dipping procedure (150 mg kg−1 for 1 h). Both GA3-containing soil paste (25 mg kg−1) and gelatinized starch (860 mg kg−1) were applied to tuber heads of Dioscorea alata and D cayenensis-rotundata in the Ivory Coast. Soil paste, gelatinized starch and dipping consistently prolonged dormancy and reduced fresh matter losses by 23–39% in D cayenensis-rotundata 3-year means. Although dipping reduced the storage losses most efficiently, soil paste and gelatinized starch used considerably less GA3. Both new treatments were easily prepared and quickly applied. Soil paste was most effective when the treatment was repeated before the end of dormancy. The third new method, spraying the tubers with a GA3 solution (150 mg kg−1), was not effective.In general, the optimal time of application was immediately post-harvest. For D alata, treatment only 1 month after harvest was particularly ineffective, whereas D cayenensis-rotundata tubers could be treated with some effect up to the end of dormancy. To achieve extended storage periods of healthy tubers of D cayenensis-rotundata, GA3 application may be recommended as post-harvest practice. Copyright © 2003 Society of Chemical Industry

Plant regeneration via somatic embryogenesis was achieved in callus cultures derived from nodal explants of in vitro grown seedlings and excised mature zygotic embryos of three bamboo species on Murashige and Skoog's (MS) basal medium supplemented with 0.5 mg/l kinetin (Kn), 2.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), 10 mg/l adenine sulphate (Ads) and 3% (w/v) sucrose incubated in the light or in the dark. Somatic embryos germinated (95–98%) into normal plants and were transferred to soil with 95% success. In vitro flowering was induced on shoots developed from nodal explants taken from somatic embryo regenerated plants of Bambusa vulgaris, Dendrocalamus giganteus and Dendrocalamus strictus on half-strength MS basal medium supplemented with 0.25 mg/l indole-3-butyric acid (IBA), 0.5 mg/l Ads, 0.5 mg/l gibberellic acid (GA3) and 3% sucrose.

The control of dormancy in yam (Disocorea spp.) tubers is poorly understood and attempts to shorten the long dormant period (i.e. cause tubers to sprout or germinate much earlier) have been unsuccessful. The aim of this study was to identify and define the phases of dormancy in Dioscorea rotundata tubers, and to produce a framework within which dormancy can be more effectively studied.

Direct differentiation of shoot buds from the collar region of hypocotyl segments of Coffea canephora was obtained on Murashige and Skoog (MS) medium supplemented with 40 μM silver nitrate (AgNO3) and growth regulators indole-3-acetic acid (IAA) and N6 benzyladenine (BA). The highest response to shoot differentiation of 60% frequency and the maximum number of multiple shoots (2–3) per explant were obtained on MS medium containing 8.87 μM BA and 2.85 μM IAA. Apart from this, 70% of hypocotyl explants produced yellow friable embryogenic callus and also globular primary somatic embryos. Subsequent transfer onto the same medium induced secondary somatic embryogenesis. The micro-shoots, upon transfer to the same medium, in the following 6 weeks developed into 4-cm-long shoots with a single root. Further subculturing onto the same medium induced 4–5 roots in a 4-week period. The resulting plantlets were hardened and transferred to micro-pots containing sand:compost mixture (1:2), where 65% of them survived and resumed growth. By using optimal levels of AgNO3, it was possible to obtain effective direct organogenesis and embryogenesis. This system was used for genetic transformation using Agrobacterium tumefaciens. A stable transformation frequency of 2–5% was obtained when both types of explants, i.e., hypocotyl explants with collar region or hypocotyl explants without collar region, were co-cultivated with A. tumefaciens GV 3101 harboring pCAMBIA 1305.2 binary vector. This is the first report of a hypocotyl collar region-based Agrobacterium-mediated transformation protocol for the economically important tropical plant C. canephora.