جستجوی مقالات مرتبط با کلیدواژه « gibberellic acid » در نشریات گروه « علوم پایه »

Dunaliella salina is a carotenoid-producing microalgae that is important for its extraordinary ability to accumulate ß-carotene. Therefore, an experiment was performed to investigate the effect of different concentrations of gibberellic acid on growth, accumulation of chlorophyll pigments, carotenoid content, and dry biomass of D. salina in f/2 medium. Experimental treatments included different concentrations of gibberellic acid (GA3): 0 (control), 0.5, 5, 10 and 20 mg/L. The measured traits in this experiment included growth rate and doubling time, chlorophyll a, chlorophyll b, total chlorophyll, total carotenoid, dry biomass, total lipid content, and endogenous gibberellic acid. The analysis of variance showed that the effect of different concentrations of gibberellic acid on all studied traits in D. salina was significant at the statistical level ρ)≤ 0.05). Gibberellic acid (GA3) at a concentration of 10 mg/l increased growth rate, chlorophyll a and b content, total chlorophyll content, dry biomass and total lipid content in the studied microalgae. While the highest amount of total carotenoid accumulation was recorded for 5 mg/L GA3 treatment. According to our findings, it is suggested that 5 mg/L GA3 concentration can be effective, if the purpose of cultivating this microalgae species is to produce carotenoid, but if the aim of production are dry biomass and total lipid content, the use of 10 mg/L GA3 concentration will stimulate and increase the production of microalgae total lipid and dry biomass.

In this study, the effect of gibberellic acid on vegetative and heterocyst cell size, inducing sugar and protein content was investigated in Anabaena at three durations (7, 14 and 21 days). According to the results, vegetative cell size did not show any significant differentiation under gibberellic acid treatments and time duration. Length and width of heterocyst cells showed a significantly different impact only with 10µM gibberellic acid at 7-day-old cultures. Algae treated with gibberellic acid had more fresh weight. Gibberellic acid induced heterocyst formation after 14 and 21 days. The amount of photosynthetic pigments increased in the 7 and 14-day cultures and decreased in the 21-day cultures. Application of gibberellic acid to the culture medium did not affect heterocyst percentage after 7 days, but it increased the heterocyst numbers in the 14 and 21-day cultures. Reducing sugar content changed dependence of gibberellic acid concentration and growth period. Treatment with gibberellic acid could increase protein content at different concentration and growth period. The results of this research showed notable effect of this plant growth regulator on Anabaena.

Stone fruits are valuable because of high nutritional. propagation of the same rootstocks is vital in horticulture. The aim of the present study was to investigate some concentrations of growth regulators such as benzylaminopurine (BAP), gibberellic acid (GA3), naphthalene acetic acid (NAA), indole butyric acid (IBA) in shoot germination and rooting of myrobalan 29c. This experiment was performed in a completely randomized block design with three replications (at least 5 samples per replication) in 14 experimental groups (G1-G14). In this study, MS culture medium and growth regulators of BAP (0, 0.5, 1 and 2 mg/L), GA3 (0, 0.1 and 0.2 mg/L), NAA (0 and 0.1 mg/L) was used in shoot generation. The results show that shoot generation varies between 1.05 in G1 group to 8.27 in G6 group. The shoot length varies between 2.87 cm in G5 group to 4 cm in G6 group. The best shoot generation was observed at concentrations of 1 mg/L BAP, 0.1 mg/L NAA and 0.2 GA3 at 8.27 numbers. The 1/2 MS medium and growth regulators of IBA (0, 0.25, 0.5 and 1 mg/L) and NAA (0, 0.25, 0.5 and 1 mg/L) were used for rooting. The results show that rooting varies between zero numbers in the G1 group to 7.6 numbers with 8.78 cm length in the G13 group. The best rooting was obtained at 1/2MS with 0.5 IBA and 0.25 NAA concentration with 7.6 root numbers.

In order to investigate the pre-harvest and priming application effects of gibberellic acid, salicylic acid and nitrogen on seed germination indices of Echinacea purpurea, this experiment was designed on factorial experiment in base completely randomized design with three replications at 2018 in field conditions and laboratory in the department of horticultural science of Ilam University. Experimental factors included gibberellic acid at two concentrations (100 and 200 mg/L), salicylic acid at two concentrations (100 and 200 mg/L) and nitrogen (from urea sorce) at two concentrations (3 and 6 g/L) that were investigated separately and in combination with each other. Treatments were applied with control samples as pre-planting (before maturity and seed harvesting) and seed priming (after seed harvesting). The results showed that the highest germination percentage, vigor index and shoot length were obtained in pre-harvest interaction with gibberellic acid 200 mg/L and nitrogen 6 g/L. The highest germination rate was observed in gibberellic acid 200 mg/L and the highest seed dry weight was obtained in gibberellic acid 100 mg/L. The highest root length was observed in pre-harvest treatment with 200 mg/L of gibberellic acid and 200 mg/L of salicylic acid. Also, pre-harvest nitrogen treatment had significantly higher germination percentage, germination rate, vigor index, shoot length and dry weight than their priming. Therefore, in present study, preharvest treatments of gibberellic acid in combination with nitrogen or salicylic acid were introduced for improving the seed germination of Echinacea purpurea.

Recently, plant-derived smoke has been included in the group of growth phytohormones due to its bioactive compounds on biological and biochemical processes. In order to evaluate the phytohormones-like effects of Papaver rhoeas L. smoke derived on some biochemical characteristics of medicinal plant basil an experiment was conducted with repeated measurements in research greenhouse of Campus of Agricultural and Natural Resources of Razi University in 2017. The Experimental treatments included eight levels of leaf foliar application (control, Smoke-water in 100, 5000, 1000 and 5000 dilutions accompanying with cytokinin, auxin and gibberellic acid (each of them with concentration 50 µM)) with 3 replications and 2 harvest stages. The results indicated that application of smoke-water (1:500 and 1:100 (v/v)) improved gas exchange status and also increased chlorophyll content, without significant difference with cytokinin. All chlorophyll fluorescence parameters also increased significantly under the application of phytohormones and smoke-water. Levels of foliar (especially SW: 1:500 and 1:100 (v/v)) reduced electrolyte leakage of plasma membrane and content of soluble carbohydrates. The highest total phenolic and anthocyanins content was obtained from leaf foliar in the smoke-water of 1:100 and 1:500 (v/v), respectively. Smoke-water at concentration 1:100 (v/v) without significant difference with phytohormones auxin and gibberellic acid significantly increased the activity of peroxidase. In general, it can be concluded that aqueous extracts of plants-smoke derived (especially SW 1:100 (v/v)) without significant differences with synthetic phytohormones have the ability to reduce the biochemical limitations of basil and can improve its growth conditions.

Drought is a serious problem for production of crops such as bean which is sensitive to this stress. Therefore use of management methods to reduce the effects of drought is very important. To evaluate the effects of foliar application of glycine betaine (GB) and gibberellic acid (GA) on qualitative and quantitative characteristics under drought stress conditions, a factorial split plot experiment based on randomized complete block design with three replications was conducted during the 2018 crop year. Experimental factors included irrigation regimes (50, 70 and 90 mm evaporation from Class A evaporation pan) in main plots and glycine betaine (no foliar application, 50 and 100 mM) and gibberellic acid (no foliar application, 60 and 120 ppm) were in factorial form in sub plots. Data were collected on proline, malondialdehyde, catalase, superoxide dismutase, guiacol peroxidase, ascorbate peroxidase, glycine betaine, gebberellic acid, protein content and protein yield. The results of ANOVA indicated that the effects of irrigation regime, glycine betaine and gibberellic acid were significant for all the studied characteristics. The results of comparison of means showed that by increasing drought stress the gebberellic acid value, protein content and protein yield decreased but the proline, malondialdehyde, catalase, superoxide dismutase, guiacol peroxidase, ascorbate peroxidase and glycine betaine significantly increased. The exogenous application of glycine betaine and gebberellic acid at all levels of drought stress decreased malondialdehyde, catalase, superoxide dismutase, guiacol peroxidase, ascorbate peroxidase and increased the proline, glycine betaine, gebberellic acid, protein content and protein yield. Generally, the results of this study showed that the exogenous application of glycine betaine and gibberellic acid improved the growth of cowpea by reducing the adverse effects of drought stress. Therefore, exogenous application of glycine betaine and gibberellic acid can be used as a useful method for improving drought tolerance in cowpea. Also, the results showed that concentrations of 100 mM glycine betaine and 120 ppm gibberellic acid were more effective than other levels and induces more water stress tolerance in cowpea.

One of the characteristics of ornamental leaf plants is produce enough leaves and side branches to create a dense appearance. In some cases it is necessary to treatment non-causing varieties branch with some of the growth hormones to produce enough leaves and side shoots to achieve this goal. The most common treatment-causing agents are topping the branch and gibberellic acid that produce foliage in plant. This research was conducted in order to influence the topping and application of gibberellic acid on vegetative and reproductive growth of seasonal flowers African marigold. Topping stimulate lateral buds and produced more lateral branches. In this study topping as a first factor in three levels (0, 45 and 90 days before transplanting) and Gibberellic acid as the second factor in four levels (100, 200 and 300 mg / lit) were used in pot and in the open air under a factorial experiment with a completely randomized design (CRD) in 4 replicates in 4 pots. The seeds were planted in late summer. After six leaflets in (7 cm) seedlings were transferred to pots. Flowers in vases were deployed after (15 to 20 days after transplanting) were treated with gibberellic acid and topping. Spraying was carried out in three stages at intervals of 10 days. Distilled water was used to control plants. The results showed that the use of gibberellic acid combined with a topping treatment at 120 days after spraying increases the amount of chlorophyll index, plant height, length and lateral root volume. The number of open flower, bud and stem diameter had highest performance in the 120 days after spraying the treatment of100 mg/lit of gibberellic acid, respectively. Therefore topping combined with gibberellic acid at a concentration of 200 ppm gibberellic acid increases morphological growth, flowering and chlorophyll and carotenoid synthesis to accelerate significantly the African parsley.

Considering low vigor of Stevia (Stevia rebaudiana Bertoni) seeds and difficulty of its germination, the purpose of this experiment was to evaluating the effect of different priming types on germination and seedling growth of Stevia in the presence of gibberellic acid. A factorial experiment was carried out based on a completely randomized design with three replications. Treatments consisted of different concentrations of gibberellic acid (G1=0, G2 =25 and G3=50 mg L-1) and seed priming as hydro, hormone (gibberellic acid, 0.2 mg L-1) and Osmo (3% potassium nitrate) for 18 hours. The essential oil constituents were measured by gas chromatography (GC). The activity of hydrolytic and antioxidant enzymes in seedlings also were measured. The highest germination percentage (67.26 %) observed in the hormone priming and the concentration of 50 mg L-1 of gibberellic acid. Osmopriming had the highest germination rate. The highest levels of SOD activity and MDA content observed in osmopriming and catalase and peroxidase achieved in hydro priming without application of gibberellic acid. The highest level of alpha-amylase enzyme activity was related to hormone priming with 50 mg L-1 gibberellic acid. The highest levels of alphacadinol, methyl salicylate and Safranal and also carbohydrates and protein observed in hormone priming and 50 mg L-1 gibberellic acid. In conclusion, to achieve the highest essential oil contents in Stevia using hormone priming and application of 50 mg L-1 gibberellic acid was suitable.

Cynodon dactylon is the herbaceous, perennial, thermophilic and creeping plant of the grass family which, as an autochthon plant resistant to drought, has a major importance from the medical, economic and environmental aspects. The present study was performed to evaluate the effect of pretreatment on germination and plant growth characteristics of C. dactylon, in a completely randomized design (4 replicates). The treatments consisted of potassium nitrate (0.1, 0.2 and 0.3 %), for 10 hours, salicylic acid (100, 200 and 300 mg/l) for 12 hours and gibberellic acid (GA3) (125, 250 and 500 mg/l) for 12 hours and distilled water was used as control. The results of analysis of variance showed that the applied stimulus have a significant influence on the percentage and germination rate, vigor index of the seed, root length, stipe length and seedling length within probability level of 1. In general, among the applied treatments, pre-soaking with salicylic acid concentrations (100, 200 and 300 mg/l) had the most positive impact on the characteristics of seed germination of C.dactylon.

In order to investigate different treatment effects on germination in Gundelia tournefortii, three factorial experiments were carried out in the completely randomized design with three replications. The first factor was stratification at 4oC in three levels including 0, 3 and 6 weeks, the second factor was mechanical scarification in two levels including seeds with/without scarification and the third factor was chemical treatments of seed dormancy breaking in three levels including distilled water and gibberellic acid at concentrations of 1000 and 1500 mg/l and Thiourea 0.1%. The results showed that the effects of stratification, scarification and chemical treatments of dormancy breaking and their interactions were significant on all studied parameters (p

Thyme is one of the best known genera within Labiatae family, because of its more than 250 species and its antimicrobial and antispasmodic uses. At the present time, demand for thyme products are increasing and hence research demand is increasing. Environmental factors such as drought can affect plant growth and production. Phytohormones take a crucial role in this stress. Indicated T. serpyllum as the most tolerant and T. vulgaris as the most susceptible genotypes to water deficit stress been used. At the end of stress period, shoot dry weight , water content, water potential and soil moisture were measured. Based upon these traits, tolerant plants known as water saver plants, while, sensitive plants behaved as water spender plants. This experiment was conducted at the University of Birmingham, School of Biosciences in 2013. During the stress, leaf samples were harvested and analyzed through mass spectrometry based metabolomics approach. The results of tolerant plants indicated significant increase in drought-stressed plant rather than control plants as follows: 173% increase in salysilic acid, 133% increase in neoxantin (abscisic acid substrate), 166% of auxin and 180% of gibberellic acid. Nevertheless, sensitive plants showed significant increase in jasmonic acid 132%, salysilic acid 242% and decrease in neoxanthin 62% and gibberellic acid 36%. Auxin had non-significant difference between stressed and control plants of sensitive populations. Increasing of neoxanthin in tolerant plants occurred with water content maintenance and decreased shoot dry weight. This experiment confirmed the key role of abscisic acid and salysilic acid in drought stress tolerance mechanism. Even though, it seems overall response of plant to drought stress is the result of all the phytohormones interaction. Increasing ABA precursor caused growth inhibition in drought tolerant plants, which eventually provided less water usage. Since, sensitive plants didn’t exhibit neoxantin elevation, which seems it is due to being lower than water potential threshold.

This research for evaluated the effect of Gibberelic acid, Salicylic acid Benzyl adenine in pre and postharvest stage on some physicochemical and enzymes traits and vase life of Gerbera jamesonii is one of the most popular cut flowers that its production has increased in global markets and Iran for enhance the quality, shelf life and minimize postharvest losses in cut flower, done. For this purpose, an experiment based on completely randomized design with 8 treatments and 3 replications on cut flower gerbera 'Sorbet' were performed. In the first experiment, pulse treatment (24 hours), BA, GA3 and SA in 2 levels (50, 100ppm) and preservative solution of silver nano particles 3 ppm with 3% sucrose was used. Sliver nano particles3 ppm with 3% sucrose and distillated water were used as control. In the second experiment, spraying before harvest, BA, GA3 and SA in 2 levels (25, 50 ppm) was performed and then cut flowers transferred to preservative solution of silver nano particles 3 ppm with 3% sucrose. Sliver nano particles 3 ppm with 3% sucrose and distillated water were used as control. During experiment traits including vase life, relative fresh weight, and cell membrane stability index, anthocyanins of petals, phenylalanine ammonia lyase and super oxide dismutase enzymes activity was investigated. The results showed that in both experiments there were significant differences between the treatment and control, among of concentrations of BA, GA3 and SA, in the first experiment, SA 100 ppm and in the second experiment, salicylic acid 50 ppm and then preservative solution containing silver nano particles with sucrose, have the most favorable effect on quantitative and qualitative, enzymatic traits and vase life compared to other treatment. Correlations between traits in both experiments also indicate a significant positive correlation at 1% among vase life of gerbera cut flowers with all traits.

Drought stress stimulates reactive oxygen species production in plant chloroplast and reactive oxygen species cause peroxidation of lipid membrane and destruction of cell membrane. Moldavian dragonhead Dracocephalum moldavica L. is one of the aromatic and medicinal plants which use as healing of wound. In this research gibberlin use in order to control oxidative stress to tolerate water shortage and fluctuation in leaf pigments and total phenol were investigated. Therefore, an experiment was conducted in factorial design based on completely randomized design with four replications. Irrigation factor were in three level Fc (without stress), 2/3FC (moderate stress) and 1/3FC (severe stress) and gibberellic acid were in two level including and 100 mM. The results of experiment showed that by increasing of stress severity chlorophyll a, b and a+b content decreased. However, flavonoid, anthocynin and phenol content increased. Because of dehydration effect, β-carotene and xanthophyll content increased only in moderate stess. Gibberellic acid increased cholorophyll content, Hill reaction rate and phenol content. But There was no considerable change in Flavonoid and anthocyanin amount. According to result, exogenous gibberellic acid increased drought response of Moldavian dragonhead with various mechanism and trigger to increase phtosythesis rate in plant.