Comparison of the Effects of Saline and Alkaline Stress on Growth, Photosynthesis and Water-Soluble Carbohydrate of Oat Seedling (Avena sativa L)

Abstract

High-quality arable land is necessary for human socio-economic development, but up to 60% (0.9 x 109 ha) of the world’s arable land is considered too saline and/or too alkaline for agricultural use, it severely affect agricultural productivity (Richards 1990; Allakhverdiev et al., 2000; Lauchli and Luttge 2002). The main ions in salt soil are Na+, K+, Cl– and NO3– in the salt soil, the saline stress usually had been defined two distinct kinds of stresses: saline stress and alkaline stress (Shi and Yin 1993). Saline stress generally involves osmotic stress and ion injury, but alkaline stress not only included osmotic stress and ion injury, but also has high pH effect (Yang et al., 2009a). The high pH environment surrounding the roots can directly cause mineral elements availability significantly decreased and Ca2+, Mg2+ and H PO3to precipitate, which possible inhibit ion uptake and disrupt the ion homeostasis of plant cells (Shi and Wang, 2005; Xue and Liu, 2008). Oat is one of the major economic and ecological food crops in the world, and it is a kind of low sugar, high protein, fat and energy foods, it’s exposed to multiple environment stresses, including drought, salinity etc (Shtangeeva and Ayrault, 2007). But salinity and alkalinity are significant constraints on the productivity of oat, a major staple cereal crop with global socioeconomic importance (Gale, 2005). The tolerance of oat has been widely studied; its physiological characteristics enable it to tolerate saline stress, however there were only a few researches on alkaline stress. In this study, the aim was to analyze and compare the growth, photosynthesis and water soluble carbohydrate in oat seedlings under saline and alkaline stresses, to determine and elucidate how high pH levels cause damage to oat seedlings tissues and how oat adapt to overcome alkaline stress. The goal can be achieved either by improving the soil or planting crops that are tolerant to both saline and alkaline stress.