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Showing 3 results for Osmotic Adjustment

I. Yousefi Javan , F. Gharari ,
Volume 9, Issue 4 (12-2018)
Abstract

Aims: Osmotic stress such as drought, salinity, and cold is one of the most important stresses. The aim of this study was to isolate and evaluate the genes of AREB and MPK2 in order to study the resistance to drought of tomato plants.
Materials and Methods: In this experimental study, seeds of two varieties of Tomato (Red Cloud) and (Peto Pride; resistant and susceptible to drought stress, respectively) were grown in drought treatment levels of -2 and -4. This study used 3 replications by a model based on a completely randomized block design. Sampling was done for Thiobarbituric acid reactive material (TBARM) for each treatment in 3 replications. Randomized and repeated sampling were done for molecular studies and the genes expression. AREB1 and MPK2 genes were studied, using bioinformatics resources and with the help of specific primers, making cDNA, PCR, and Electrophoresis. The analysis of variance test and SPSS 15 software were used
Findings: With increasing drought stress, most of morphological traits had a considerable decline, but cellular oxidative index increased with the increase of stress, so that TBARM increased. The expression of AREB1 was higher than that of MPK2 gene expression. The rate of similarity between LeAREB and kinase 2 protein sequences in resistant tomatoes was 31%.
Conclusion: With increasing drought stress, most morphological traits have a significant decline, but TBARM shows a significant increase with increasing stress. The AREB1 resistant drought gene is induced by the effects of drought stresses, while the expression of the MPK2 gene does not show a significant difference.


Volume 17, Issue 5 (9-2015)
Abstract

Vicia sativa L., an annual winter growing leguminous plant, is a valuable source of protein and minerals for cattle. Drought is one of the key stress factors that influence plant growth and development. In order to investigate common vetch physiological and molecular responses under Normal irrigation (N) and two levels of drought stress [S1= 30% and S2= 10% Field Capacity (FC)], a greenhouse experiment was carried out on two genotypes, namely, Mahalimaraghe and 41,and some physiological traits [e.g. Relative Water Content (RWC), Electro Leakage (EL), total protein, chlorophyll (a, b), and carotenoid content] were measured and expression patterns of three genes (sod, aq1 and bzip) were evaluated by real-time quantitative RT-PCR analysis. Results showed that expression pattern of all three genes and physiological responses had significantly changed in response to the stress. The highest increase in the expression of each of the three genes was observed in Mahalimaraghegenotype in S1 condition compared to N. In contrast, under S2 condition compared to N, the highest increase in expression of the three genes was observed in genotype 41. In comparison of S2 with S1, the highest changes in expression of all the three genes was observed in Mahalimaraghe genotype. All together, the obtained results may facilitate the understanding of molecular mechanism of V. sativa in response to drought stress, and also provide the basis of effective genetic engineering strategies for improving stress tolerance of V. sativa.

Volume 18, Issue 2 (3-2016)
Abstract

In order to determine the best growing media for Gerbera jamesonii under alkaline conditions, a factorial experiment was conducted with two factors, namely: (i) Growing medium, and (ii) Concentrations of bicarbonate (NaHCO3) in nutrient solution. Results showed that increasing the concentration of NaHCO3 from 0 to 40 mM in nutrient solution significantly decreased plant growth, maximal quantum yield of PSII photochemistry (Fv/Fm), photosynthesis Performance Index (PI), Glutamine Synthetase (GS) activity, Leaf Relative Water Content (LRWC), Chlorophylls (Chl a, b and total Chl) and carotenoids. Under alkalinity stress, reduction in vegetative growth, Fv/Fm, PI, LRWC, GS activity and photosynthesis pigments content was the lowest in Coconut Fiber (CF) substrate compared to the other substrates. Furthermore, plants grown in CF substrate had higher soluble sugars and proline content than those in other substrates. On the other hand, plants grown on Perlite (P) substrate had the highest reduction in growth and physiological characteristic in alkaline conditions. The alleviation of alkalinity-induced growth inhibition of plants by CF substrate may be related to improvement of photosynthesis, enhancement of GS enzyme activity and osmotic regulation. It is concluded that the use of CF substrate could provide a useful tool to improve alkalinity tolerance of gerbera plants under NaHCO3 stress.

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