Effects of NaHCO3 Acclimation on Rye (Secale Cereale) Growth Under Sodic-Alkaline Stress.

Liyun Liu,Hirofumi Saneoka

doi:10.3390/plants8090314

Abstract

Sodic-alkalinity is a serious limiting factor in agricultural productivity. This study was conducted to examine the contribution of acclimation to the adaptation of rye (Secale cereale) to sodic-alkalinity. Effects of acclimation were determined in two sets of experiments: One experiment for mineral accumulation, antioxidative capacity, and other physiological parameters; and a vivo experiment for root Evan’s Blue and Na+ influx from medium to root. Being exposed to sodic-alkalinity, acclimation did not affect plant dry weight. However, acclimation significantly reduced Na+ concentration and maintained a lower Na+/K+ ratio in all the tissues, increased the Ca2+ and Mg2+ concentrations in the root tissues, and increased the water uptake ability in comparison to the non-acclimated plants. Acclimation increased the antioxidant capacity represented by the increased activities of the enzymes SOD, GR, CAT, and GPOX in the leaf tissues of acclimated plants in comparison to the non-acclimated plants. Moreover, acclimation increased the root cell viability inhibited the Na+ influx to the root tissues in comparison to the non-acclimated plants. Together, these results suggest that rye can acclimate to sodic-alkalinity by increasing root cell viability, and therefore limited Na+ influx to root tissues and increased water uptake and antioxidant capacities without any change in the plant growth.

Highlights

The progressive increase of world population requires the agricultural productivity to keep up with the food demand
Acclimation increased the antioxidant capacity represented by the increased activities of the enzymes Superoxide dismutase (SOD), glutathione reductase (GR), CAT, and guaiacol peroxidase (GPOX) in the leaf tissues of acclimated plants in comparison to the non-acclimated plants
These results suggest that rye can acclimate to sodic-alkalinity by increasing root cell viability, and limited Na+ influx to root tissues and increased water uptake and antioxidant capacities without any change in the plant growth

Summary

Introduction

The progressive increase of world population requires the agricultural productivity to keep up with the food demand. It is necessary to study the possibility of enhancing the crop productivity by improving the crop ability to cope with various environmental stresses. Acclimation is the phenomenon of plants improving their physiological ability to adapt to various environmental changes. Some plant species such as soybean, maize, pea, and mungbean, increased the ability to tolerate salinity after being exposed to low levels of stress for a period of time [1,2,3,4,5]. The better performances of acclimated plants are consequences of reduced accumulations of Na+ in soybean leaf tissues and in maize root tissues [1,5], better regulation of xylem ion loading (decrease of xylem Na+ /K+ ) in pea [4], and enhancement of the antioxidant defense system and osmolyte accumulation in mungbean [3]. Salinity is considered a soil with excessive NaCl or a mixture of NaCl and

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