Influence of Soil Salinity on Growth and Physiological Indexes of Phoenix canariensis Seedlings

Abstract:

The growth and physiology characteristics of Phoenix canariensis seedlings were studied cultured on different soil salinity ranged from 1.2 to 14.5. The results showed that the number of new leaves decreased and death leaves increased with soil salinity increment. The chlorophyll content increased under high soil salinity, while chlorophyll a/b increased under low salinity and declined under high salinity more than 5.1. MDA content maintained about 4.30 μmol g^-1 under salinity from 1.2 to 5.1, then increased with soil salinity. The SOD activity increased under low salinity, while decreased rapidly when salinity higher than 10.8. Under salt stress, Na⁺ and Cl^-contents in leaves increased, while K⁺, Ca²⁺ and Mg²⁺ contents and ratio of K⁺/Na⁺ declined. The main reasons of growth decline under salt stress were effective photosynthetic area decrease and destroy of ions balance. These indicated that Phoenix canariensis displayed high resistance to salt stress was suitable to plant widely in coastal districts, which could grow normally under soil salinity lower than 5.1 and only shown damage symptoms above salinity of 10.8.