EFFECTS OF SALINE-ALKALI STRESS ON GROWTH AND PHYSIOLOGY OF AMORPHA FRUTICOSA L. SEEDLINGS

This study determined the effects of salt stress (NaCl) and alkali stress (Na2CO3) on the growth and physiology of Amorpha fruticosa seedlings. The results showed that salt and alkali stress inhibited the growth of root, stem and leaf, but the appropriate concentration of salt and alkali stress could stimulate root elongation. Salt stress and alkali stress resulted in the decrease of photosynthetic capacity of seedlings. The degree of Na+ absorption by the roots is relatively low, and a large amount of Na+ absorbed into the body is separated in the stem and total petiole. The concentration K+, Ca2+ and Mg2+ in diverse plant organs significantly changed under both stresses while concentration of K+, Ca(2+ )and Mg2+ in leaflets did not change significantly. In addition, accumulation of Cl- under salt stress was not obvious. Soluble sugar accumulation in roots and lobules remarkably increased under both stresses. The distribution of soluble sugar in each vegetative organ was changed. The absorption of degree of harmful ions was relatively low, and more harmful ions were accumulated in the stem and total petiole. This was the response strategy of the seedlings to adapt to salt and alkali stress and it provides a theoretical basis for planting Amorpha fruticosa in areas with relatively low salinization degree.