A pot experiment was performed as factorial based on randomized complete block design with three replications, to assess the effects of 1 mM spermidine (SPD) and 1 mM putrescine (PUT) on Indian mustard (Brassica Juncea L.) under different levels of watering (100, 75, 50 and 25% of field capacity). Chlorophyll a and b contents decreased, but the ratio of Chl a/b and carotenoid content increased with decreasing water supply. Foliar sprays of polyamines improved chlorophylls a and b and carotenoid contents, while the ratio of Chl a/b was reduced by these growth regulators. Relative water content, glycine betaine, proteins and soluble sugars contents were increased, but proline content was decreased by exogenous polyamines under limited water supply. Antioxidant enzyme (POX, CAT, SOD and APX) activities were enhanced by drought stress and polyamine treatments. This resulted in lower electrolyte leakage and lipid peroxidation (less MDA) under stressful conditions. The present results indicate that exogenous polyamines such as putrescine and spermidine can alleviate some of the deleterious impacts of water limitation on Indian mustard.
314Elham mostafaEi et al.
Acta Biologica Hungarica 69, 2018ing [31]. When environmental condition is favorable for plants, ROS is constantly generated at low levels scavenged then by various antioxidant mechanisms [14]. However, higher production of ROS under environmental stresses can damage the cells by peroxidation of lipids, oxidation of proteins and enzyme inhibition [41]. To avoid potential damage caused by ROS to cellular components, as well as to maintain growth, metabolism, development, and overall productivity, the balance between production and elimination of ROS at the intracellular level must be rigorously regulated. This detoxification of ROS could be achieved by enzymatic and non-enzymatic antioxidants [26,27].Brassica oilseeds are the major world source of vegetable oil. These crops represent a substantial contribution to the production of food, and almost their all parts are used in human livelihood. Its oil has special fatty acid profile and rich source of natural anti-oxidants and other cytotoxic phytochemicals. However, over the past couple of decades Brassica oilseeds has become a more dependable source of erucic acid [44]. Brassica developes will in high rainfall areas, whereas it grows, little in low rainfall areas [37]. Reduction of the yield of Brassica due to drought stress has been reported by a number of authors [24,33]. However, the influence of various exogenous growth regulators in alleviation of drought stress is still less known.Polyamines are unsaturated hydrocarbons, with two or more primary amino groups. The diamine putrescine and triamine spermidine are ubiquitous in nature [40] and involved in a variety of processes, such as transcription, RNA and protein synthesis and enzyme activation [45]. A number of physiological regulatory process involved in the control of cell division, embryogenesis, root formation, fruit ripening, perception of biotic and a...
