Akbar Norastehnia, Gohar Yousefzadeh,
Volume 3, Issue 4 (12-2016)
Abstract
Application of some chemical components including plant hormones such as methyl jasmonate causes resi-stance to increase in environmental stresses. In this study, the effect of metyl jasmonate in different concentrations (10, 20 and 30 uM) on the elevation of the plant resistance was investigated in drouht stress. Tobacco seedlings were studied under drought stress caused by polyethylene glycol (20%) during periods of 3, 6 and 9 days. The results revealed that the imposed stress significantly increased soluble sugar content, MDA and non-enzymatic defense factors such as ant-hocyanin and proline. In contrast, it is reduced the amount of photosynthetic pigments, carotenoids and flavonoids. On the other hand, the use of methyl jasmonate decreased malondialdehyde as a marker of lipid peroxidation and values of some detent factors such as proline, beta-carotene and MDA. Meanwhile, it increased the amount of soluble sugars and photosynthetic pigments, anthocyanins, flavonoids and flavonols. As a result of the simultaneous reduction of lipid pe-roxidation and some antioxidants, it seems that using exogenous methyl jasmonate can help the plant withstand against drought stress conditions.
Mohsen Alizadeh, Nezam Armand, Maryam Rahimi, Shokoufeh Haji Hashemi,
Volume 9, Issue 1 (3-2022)
Abstract
Seaweed extract can improve the physicochemical properties of the soil and has a favorable effect on the plant growth and development due to having high nutrient content, high water holding capacity, plant growth regulators and beneficial microorganisms. The aim of this experiment was to investigate the effect of Ascophyllum nodosum extract, a brown alga, on the morphophysiological characteristics of bean plant (Phaseolus vulgaris) under water stress. The experiment was performed in a Completely Randomized Factorial Design with three replications. Experimental treatments included 4 concentrations of foliar application of seaweed extract (0, 0.2, 0.4 and 0.6%) and 3 levels of water stress including no stress, mild stress and severe stress (irrigation at 75, 50 and 25% of field capacity, respectively). The results showed that the interaction effects of stress and algal extract on the evaluated traits were not significant. However, the seaweed extract significantly increased the leaf area, number of the leaves, leaf length, surface and length of the roots, root dry weight, the content of chlorophyll a and b and the total chlorophyll content. Application of algal extract at levels of 0.2 and 0.4% caused a significant increase in the evaluated parameters as compared with the control plants. The evaluation of water scarcity stress effects showed a significant reduction in the all studied characteristics in accordance with increasing water stress level from 75% to 25% of field capacity. The results of this study showed that foliar application of seaweed extract significantly increased some morphological and photosynthetic properties, while water stress significantly reduced the investigated parameters.
