Showing papers by "Sowbiya Muneer published in 2019"

Silicon and Salinity: Crosstalk in Crop-Mediated Stress Tolerance Mechanisms.

Abstract: Salinity stress hinders the growth potential and productivity of crop plants by influencing photosynthesis, disturbing the osmotic and ionic concentrations, producing excessive oxidants and radicals, regulating endogenous phytohormonal functions, counteracting essential metabolic pathways, and manipulating the patterns of gene expression. In response, plants adopt counter mechanistic cascades of physio-biochemical and molecular signaling to overcome salinity stress; however, continued exposure can overwhelm the defense system, resulting in cell death and the collapse of essential apparatuses. Improving plant vigor and defense responses can thus increase plant stress tolerance and productivity. Alternatively, the quasi-essential element silicon (Si) – the second-most abundant element in the Earth’s crust – is utilized by plants and applied exogenously to combat salinity stress and improve plant growth by enhancing physiological, metabolomic, and molecular responses. In the present review, we elucidate the potential role of Si in ameliorating salinity stress in crops and the possible mechanisms underlying Si-associated stress tolerance in plants. This review also underlines the need for future research to evaluate the role of Si in salinity stress in plants and the identification of gaps in the understanding of this process as a whole at a broader field level.

Dynamic role of iron supply in amelioration of cadmium stress by modulating antioxidative pathways and peroxidase enzymes in mungbean.

Abstract: Iron deficiency and cadmium (Cd) stress causes a rapid change in plant physiology. The aim of this work was to characterize the effects of Fe supplementation on redox reactions in leguminous plants under Cd toxicity. The experiments were performed in hydroponic nutrient media, using mungbean grown under 300 µM cadmium chloride with or without Fe for 10 days. The Fe concentration in plants grown under Fe deficiency was reduced by the presence of Cd; however, it recovered to control levels after Fe was supplied. Similarly, a very high Cd concentration was observed in plants grown under Fe deficiency in the presence of Cd toxicity but when Fe was supplied the Cd concentration decreased. After 5 days of Fe deficiency, the activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione reductase and ascorbate peroxidase) were significantly higher than in plants supplied with Fe in the absence or presence of Cd. However, after 10 days of Fe deficiency, these enzyme activities were severely decreased in the presence of Cd toxicity but increased when Fe was present. The activities of other peroxidase enzymes such as guaiacol peroxidase, syringaldazine peroxidase, polyphenol oxidase and benzidine peroxidase decreased after 10 days under Cd toxicity and were further reduced in the absence of Fe. Furthermore, the level of reduced glutathione and oxidized glutathione increased for the first 5 days under Cd toxicity under Fe deficiency but was reduced after Fe was supplied to Cd-treated plants. The data indicate that supply of Fe contributes to the alleviation of Cd toxicity in redox reaction pathways in mungbean plants.