Showing 8 results for Growth Regulators
Volume 6, Issue 1 (3-2017)
Abstract
The aim of this study was to evaluate the efficacy of some insecticides with novel modes of action on Liriomyza sativae Blanchard and their sublethal effects on pupal mortality, pupal weight and sex ratio in adult insects. The effects of hexaflumuron, chromafenozide, chlorfluazuron, cyromazine, lufenuron + fenoxycarb and azadirachtin and chlorantraniliprole were evaluated on 1st instar larvae of L. sativae using a leaf dip method. Dose - response lines were constructed for insecticides which caused higher mortality of the larvae at field recommended doses. LC50 values for chlorantraniliprole, cyromazine, azadirachtin and hexaflumuron were 0.24, 0.49, 8.51 and 67.6 mg ai/l, respectively. A significant reduction in pupal weight and adult emergence was observed in all of the treatments except chromafenozide; but the adult sex ratio did not change significantly compared with control. Most of the insecticides used in this study are fairly new compounds with unique modes of action and had considerable lethal and sublethal effects on L. sativae. If these results also hold true in the field and commercial greenhouse conditions, these compounds could be suitable candidates in management of vegetable leafminer.
F. Rezanejad, A.s. Hosseini,
Volume 10, Issue 3 (9-2019)
Abstract
Physalis alkekengi L. is planted in gardens and green spaces because of the beautiful and colorful sepals surrounding the fruit. The species is widely used in traditional medicine and treating a range of diseases. Micropropagation of P. alkekengi was evaluated using the node and internode explants. After sterilization and seed germination, sterile seedlings were transformed to basal MS medium to create sterilized seedlings as a source of explants. Regeneration of nodes and internodes explants was studied at various concentrations of growth regulators of 2, 4-D and BAP as well as in medium lacking growth regulators or control (11 various media). The experiment was conducted in a completely randomized design with three replicates. The internodal explants produced shoot on media 2 (0.2mgl-12, 4-D), 3 (0.2mgl-12, 4-D+0/2mgl-1 BAP ), and 4 (0.5mgl-12, 4-D+0.2mgl-1 BAP ) and then were rooted on these media. The nodal explants in control and different hormonal treatments generated shoots; interestingly, shoots generated in control medium successfully established roots on the same medium after 7 days (70%). The other regenerated shoots in different media (10) were rooted on ½ MS medium containing 1mgl-1IBA. The rooted plants were transplanted into pots containing sand as well as perlite to be well acclimated before transfer to the greenhouse. They grew well later in the greenhouse at a 100% success This study shows high in vitro regeneration capability of this species as an important medicinal and ornamental plant. Therefore, it is suggested to use this species in molecular and genetic studies, somaclonal variation, and the production of herbal medicine.
Volume 15, Issue 5 (9-2013)
Abstract
Individual grain weight of wheat kernels differs with their positions on a spike. Cultivation practices (such as fertilizer nitrogen and plant growth regulators application) can be used to improve weight of basal and distal kernels. For this purpose, two experiments based on randomized complete block design were carried out with three replications. The aim of this research was to study the mechanisms related to sink strength as well as the regulatory factors affecting sink activity. One cultivar of a facultative wheat, cv Yangmai15, was used. Treatments of the experiments included application of nitrogen (two levels) and plant growth regulators [abscisic acid (ABA) and Fluridone (inhibitor ofABA synthesis)] in basal and distal kernels, respectively. Results showed that nitrogen application increased grain yield and its components. Grain filling in basal kernels started earlier and its rate was higher than that of the distal kernels. Nitrogen fertilizer increased the individual kernel weight both in basal and distal kernels, and the rate of increment was higher than the control, even in distal kernels. The application ofABA resulted in increase in grain weight, whereas a considerable decrease in grain weight was observed in response to Fluridone compared to the control. Nitrogen application together withABA application enhanced the activity of SuSase, AGPase, SSS, and SBE in basal and distal kernels and the increment in the activity was higher in distal kernels. It is concluded that simultaneous application of nitrogen andABA enhanced grain weight by regulating the activity of key enzymes involved in starch synthesis.
Volume 17, Issue 6 (11-2015)
Abstract
The present work developed an efficient plant regeneration and propagation system via direct organogenesis for Morinda officinalis How., a valuable endangered medicinal plant. The effects of explant types on shoot induction, plant growth regulators on shoot proliferationand elongation and the subsequent rooting ability of shoots were examined. Among the various types of explant, direct shoot proliferationwas successfully achieved from shoot tips and nodal stem segments with around 95% of the explants producing approximately 5 shoots per explant after 8 weeks of culture on optimal medium. On the other hand, leaf and internodal explants did not produce any shoots. The most effective cytokinin on shoot proliferation was 6-benzyladenine. When the concentration of 6-benzyladenine was at 1.0-2.0 mg L-1, a high mean shoot number (about 5 shoots per explant) was achieved. Shoot elongation was obtained satisfactorily by transferring the shoots to Murashige and Skoog basal media containing 2.0-3.0 mg L-1 gibberellic acid-3 within 2 weeks. Rooting was 100% on half-strength Murashige and Skoog medium containing 0.2 mg L-1 indole-3-butyric acid after 3 weeks of culture. The plantlets were acclimatized in the greenhouse and subsequently transferred to the field with 90% survival rate.
Volume 19, Issue 6 (11-2017)
Abstract
Saffron (Crocus sativus L.) is a sterile species and biotechnological method is suggested to improve different characteristic in this valuable plant. In this study, an efficient protocol was provided for callus induction and regeneration of saffron using thin cell layer explants. Longitudinally and transversally, thin cell layer explants with approximately 1 mm thickness of apical buds were cultured on MS medium supplemented with different concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D), 6-BenzylAminoPurine (BAP) and 1-NaphthaleneAcetic Acid (NAA). The highest amount of callus induction (100%) was obtained from transverse thin cell layer explants of apical bud in MS medium containing 2 mg L-1 BAP and 2 mg L-1 NAA during 3 months incubation under dark condition at 20°C. The maximum percent of shoot regeneration (75%) was observed on the MS medium containing 0.5 mg L-1 BAP. The results of this investigation revealed that the thin cell layers from buds are suitable explants for regeneration.
Volume 20, Issue 1 (1-2018)
Abstract
Possibility of improving physiological traits and minituber yield of potato cultivars (cvs. Agria and Fontane) was investigated by application of plant growth regulators (BAP, ABA and BAP+ABA) at tuber initiation stage. Regardless of the cultivars, Net photosynthesis rate (Np), actual quantum yield (Φ), stomatal conductance (gs) and Transpiration rate (Tr) of BAP-treated leaves were superior to those of the control. For Agria, the greatest Chlorophyll content (Chl) was observed in BAP-treated plants, while the highest Chl for Fontane was observed in ABA-treated plants. Increasing Np and Chl content were associated with higher Soluble Carbohydrate content (SC). BAP+ABA application increased SC of leaflets in both cultivars compared with the control. Tuber Yield per Plant (Y/P), Mean Tuber Weight (MTW), and Tuber Number (TN) were stimulated by foliar treatment of plants with PGRs compared with the untreated ones, but there were significant interactions between cultivar and hormone type. Positive correlation between SC and Y/P (r= 0.97*) and MTW (r= 0.97*) were observed in Agria. Leaf area as well as dry and fresh weight of aerial parts of the BAP+ABA-treated plants were more than the untreated plants and other PGR treatments. These results indicate that either of BAP, ABA, or their combination could be effectively used to improve physiological traits and tuber yield of these cultivars, although, Agria responded more prominently to PGRs than Fontane.
Volume 21, Issue 3 (5-2019)
Abstract
Using immature embryos that undergo somatic embryogenesis, we studied the effects of different hormonal compounds and media on controlling secondary somatic embryogenesis (SSE) in Persian oak (Quercus brantii L.). To this end, we focused on the immature embryos that were subjected to several treatments including chilling (at 4 ℃) period and SH, MS, 2,4-D, IBA, BAP, and glutamine concentrations in 5 separate sequential experiments. The results showed that, by extending chilling period to 8-weeks, SSE induction was reduced (68.75%). In different MS concentrations or MS containing PGRs, the lowest globular embryo (66%) and the secondary embryo induction (87.5%) were observed in embryos treated with MS+IBA+BA. Adding 0.75 mg L-1 glutamine to MS resulted in a decrease in the secondary somatic embryogenesis (56.25%). Among MS and SH media, 1/2 SH almost entirely controlled this phenomenon (6.25%). The highest maturation progression was obtained in the SH+glutamine treatment, which had the highest conversion to plantlet percentage (100%) and vigor index of plantlets (51.93) compared to the use of SH alone. We found that nutrient and PGR concentration were critical in embryo maturation and conversion percentage and stop the embryo induction cycle that plays a major role in secondary embryogenesis.
Volume 25, Issue 1 (1-2023)
Abstract
Elevated temperature negatively affects the production of bell pepper (Capsicum annuum L.) especially under North Indian plains where the temperature is above 40°C during summers. In the present study, the effect of exogenous application of Plant Growth Regulators (PGRs) viz. Salicylic Acid (SA) and 24-Epibrassinolide (EBR) on biochemical parameters and antioxidant system of bell pepper cv. Royal Wonder was evaluated. PGRs were applied exogenously 30, 60 and 90 Days After Transplantation (DAT). All the concentrations of PGRs i.e SA (0.10, 0.20, and 0.50 mM) and EBR (0.05, 0.10, and 0.20 µM) were effective in ameliorating the heat shock-induced effects, which enhanced thermotolerance in terms of increased proline content, soluble proteins, total phenols, total soluble sugars and starch content, improved antioxidant system (CAT, APX, POX, SOD and GR) with reduced lipid peroxidation and cellulase enzyme activity at high temperature, and, ultimately, improving total fruit yield. Application of 0.20 mM SA improved thermotolerance most efficiently at all growth stages, specifically when spray was done at 30 and 60 DAT. It resulted in a significant enhancement in biochemical parameters and antioxidant enzyme system as compared to the untreated control.