Plant growth under water/salt stress: ROS production; antioxidants and significance of added potassium under such conditions

Abstract

Plants are confronted with a variety of environmenmtal stresses resulting in enhanced production of ROS. Plants require a threshold level of ROS for vital functions and any change in their concentration alters the entire physiology of plant. Delicate balance of ROS is maintained by an efficient functioning of intriguing indigenous defence system called antioxidant system comprising enzymatic and non enzymatic components. Down regulation of antioxidant system leads to ROS induced oxidative stress causing damage to important cellular structures and hence anomalies in metabolism. Proper mineral nutrition, in addition to other agricultural practices, forms an important part for growth and hence the yield. Potassium (K) is a key macro-element regulating growth and development through alterations in physiological and biochemical attributes. K has been reported to result into accumulation of osmolytes and augmentation of antioxidant components in the plants exposed to water and salt stress. In the present review an effort has been made to revisit the old findings and the current advances in research regarding the role of optimal, suboptimal and deficient K soil status on growth under normal and stressful conditions. Effect of K deficiency and sufficiency is discussed and the information about the K mediated antioxidant regulation and plant response is highlighted.

Beneficial role of acetylcholine in chlorophyll metabolism and photosynthetic gas exchange in Nicotiana benthamiana seedlings under salinity stress

“…Greater maintenance of the tissue Na + /K + ratio reflects improved salt tolerance (Ahanger et al . ; Al‐Ghumaiz et al . ).…”

“…To prevent salinity‐mediated growth restrictions, plants up‐regulate tolerance mechanisms, including the antioxidant system and osmolyte accumulation, and efficiently compartmentalize toxic ions (Ahanger et al . ). Acetylcholine (ACh) is an intermediate in the synthesis of the key compatible osmolyte, glycine‐betaine.…”

Potential of exogenously sourced kinetin in protecting Solanum lycopersicum from NaCl-induced oxidative stress through up-regulation of the antioxidant system, ascorbate-glutathione cycle and glyoxalase system

“…Enhanced RWC due to exogenous application of cytokinins in copper and zinc treated Lupinus termis [83] and Pb-stressed safflower [62] plants has been reported, which may be attributed to increased hydraulic conductivity which is however significantly affected by stresses [84]. Proline and glycine betaine maintain water balance of plants thereby minimizing the deleterious effects of stresses on metabolism [6] particularly by protecting protein turnover, enzyme activities and the expression of stress-protective proteins [3,5,69,85]. KN mediated increased proline and glycine betaine synthesis under normal and NaCl-stressed conditions is an indicative of its protective role for metabolically important pathways by bringing osmoregulation, though the role of exogenously applied cytokinin in regulating osmotic balance is yet inconclusive (S1 Table).…”

RNA-Seq analysis of Clerodendrum inerme (L.) roots in response to salt stress

“…Salt stress induces the accumulation of toxic compounds in cells, such as the superoxide radical and H 2 O 2 , both of which are reactive oxygen species (ROS). SOD converts the superoxide radical into H 2 O 2 and H 2 O 2 is further scavenged by POD, CAT or other enzymes [55][56][57]. The Na + /K + balance in intracellular is also an important factor for plant salt tolerance.…”