Effects of NaCl Stress on the Growth and Physiological Changes in Oat (Avena sativa) Seedlings

Abstract

The oat (Avena sativa) is a kind of cereal grain, which has high saline-alkali tolerance. This experiment was carried out to investigate and compare the growth and physiological changes of oat seedling. Oat was grown under five concentrations of NaCl stress (48, 72, 96, 120 and 144 mmolL^-1). The results showed that NaCl stress had no effect on the survival rate and organic acids. With the increasing of the NaCl concentration, tiller number, the chlorophyll, K⁺, Ca²⁺, NO^3-, H²PO^4- contents, shoot length, the shoot biomass, and shoot water content were decreased significantly. However, the Cl^-, Na⁺, Na⁺/K⁺, SO₄^2- and proline contents were extremely increased. K⁺, Ca²⁺, dry weight, and water content of shoots changed greater than that of roots. While Na⁺ and Na⁺/K⁺ of shoots changed less than that of roots. When NaCl concentration was less than 96 mmolL^-1, the length, dry weight, and water content of roots had no significant changes. Based on this investigation, it can be concluded that oat seedlings accumulated more proline, Cl^- and SO₄^2- to maintaining osmotic and ion balance. In addition, NaCl stress had no significant effect on the growth of roots, and the roots can play the interceptive and protective role with a stronger salt tolerance. The roots can change the distribution of Na⁺, then it decreased the harm on the shoots and increased the tolerance of oat seedling.