Supplemental Selenium and Boron Mitigate Salt-Induced Oxidative Damages in Glycine max L.

Abstract

The present investigation was executed with an aim to evaluate the role of exogenous selenium (Se) and boron (B) in mitigating different levels of salt stress by enhancing the reactive oxygen species (ROS) scavenging, antioxidant defense and glyoxalase systems in soybean. Plants were treated with 0, 150, 300 and 450 mM NaCl at 20 days after sowing (DAS). Foliar application of Se (50 µM Na2SeO4) and B (1 mM H3BO3) was accomplished individually and in combined (Se+B) at three-day intervals, at 16, 20, 24 and 28 DAS under non-saline and saline conditions. Salt stress adversely affected the growth parameters. In salt-treated plants, proline content and oxidative stress indicators such as malondialdehyde (MDA) content and hydrogen peroxide (H2O2) content were increased with the increment of salt concentration but the relative water content decreased. Due to salt stress catalase (CAT), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glyoxalase I (Gly I) and glyoxalase II (Gly II) activity decreased. However, the activity of ascorbate peroxidase (APX), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST) and peroxidase (POD) increased under salt stress. On the contrary, supplementation of Se, B and Se+B enhanced the activities of APX, MDHAR, DHAR, GR, CAT, GPX, GST, POD, Gly I and Gly II which consequently diminished the H2O2 content and MDA content under salt stress, and also improved the growth parameters. The results reflected that exogenous Se, B and Se+B enhanced the enzymatic activity of the antioxidant defense system as well as the glyoxalase systems under different levels of salt stress, ultimately alleviated the salt-induced oxidative stress, among them Se+B was more effective than a single treatment.

Nitrogen application alleviates salt stress by enhancing osmotic balance, ROS scavenging, and photosynthesis of rapeseed seedlings (Brassica napus)

“…To adapt to the high-salinity soil environment, crops often adjust their own osmotic balance, ion distribution, reactive oxygen species (ROS), photosynthesis, and other physiological processes, 4 to reduce the toxicity of salt to their growth and development. Some studies have shown that crops respond to salt stress by reducing the osmotic potential of cells and enhancing the water absorption capacity of roots by regulating inorganic ions 5 or synthesizing and accumulating organic substances 6 in cytoplasm, to alleviate the osmotic stress caused by salt. Besides, under salt stress, crops increase the activity of antioxidant enzymes 7 and the content of small molecular antioxidants (ascorbic acid, 8 glutathione, 9 tocopherol, 10 etc.…”

Salt Stress Responses and Tolerance in Soybean

“…In our experiment, we found that soybean plants exposed to 300 and 450 mM NaCl stress showed 35 and 55%, respectively reduction in plant height. Moreover, shoot FW and DW were declined by 43 and 41%, respectively at 150 mM NaCl stress [45].…”

“…Two soybean genotypes viz. Shohag and AGS 313 were tested against salinity (50 and 100 mM NaCl) for Plant Stress Physiology -Perspectives in Agriculture different durations (15,30,45,60, and 80 d) and it was observed that salt stress caused a reduction in RWC, water retention capacity, leaf water potential, and exudation rate in a concentration and duration-dependent manner [70]. The decline in exudation rate indicated the lower flow of water into plants which is associated with lower water potential and eventually RWC.…”

“…This elevated Pro indicated B-mediated osmoregulation to enhance osmotic status (Leaf RWC) under salinity in soybean. Thereafter, Rahman et al [45] studied the response of soybean plants under varying degrees of saline condition with supplementation of B alone or in combination with selenium (Se). Although separate supplementation of B and Se caused better growth and water content in salt-stressed soybean, their combined foliar application was better to alleviate stress toxicity under different levels of severity.…”

“…Although separate supplementation of B and Se caused better growth and water content in salt-stressed soybean, their combined foliar application was better to alleviate stress toxicity under different levels of severity. For instance, the combined application of Se and B improved leaf RWC, leaf area, shoot height, and Salt Stress Responses and Tolerance in Soybean DOI: http://dx.doi.org/10.5772/intechopen.102835 FW [45]. Further comprehensive studies are required to find out how and which nutrient will give more salt tolerance mechanisms together besides their nutritional value.…”