Abstract:

Agriophyllum squarrosum is an annual desert plant adapted to mobile sand dunes in arid and semi-arid regions of Central Asia. In this study the A. squarrosum seedlings of three months were subjected to salt stress by soaked in 0-400 mmol·L^-1 NaCl solutions (in 1/2 MS medium) for 7 days separately. We examined their water contents and main mineral ion contents in their roots,stems and leaves during salt stress. The experiment results indicated that the water content of A. squarrosum seedlings reduced gradually as NaCl concentration increased, but the Na⁺ and Cl^- content kept roes observably, the K⁺ content increased in the beginning and the Ca²⁺ content cut down in root, stem and leaf.In addition,the salt ion-selective absorption coefficient S_K,Na of stem and leave increased at the beginning and then decreased, the S_K,Na of root and stem is just showed on the opposite result, and both of them reaching a critical value at 200 mmol·L^-1. Which indicated that A. squarrosum could effectively inhibit the absorption and accumulation of Na⁺ in stem and leaf at 0-200 mmol·L^-1, and Na⁺ accumulated in the stem mainly through compartmentalization function when the NaCl concentration was greater than 300 mmol·L^-1. Thus stem is the major tissue of A. squarrosum response to high salt stress because of its ability to preventing Na⁺ carrying from root to leaf.

Key words: Agriophyllum squarrosum, salt stress, mineral ion, compartmentalization