Abstract:

One-year-old seedlings of ten provenances (KM, SY, LY, LQ, CX, NJ, GY, NC, GL and HS) of Camptotheca acuminata were used to study their responses to NaCl stress. The growth and physiological and biochemical parameters were measured under treatments 3 saline concentrations including 0%, 0.2% and 0.6% NaCl ((NaCl/dried soil weight)×100%). The results indicated that 1) seedling height, base diameter and biomass tended to decrease and a ratio of roots to crown tended to increase with the development of salt stress, and the decrease in growth of LQ and CX provenances were the most; 2) under the NaCl stress, SOD activity, contents of MDA, soluble sugar, soluble protein and Na⁺ and Na⁺/K⁺ value increased but RWC declined,and contents of K⁺ and POD activity increased initially, and then decreased; 3) based on the total biomass of the provenances under the stress of 0.6% NaCl concentratior, the salt-tolerating capacity of the ten provenances was in the following order: LY>NC>GL>HS>SY>GY>KM>NJ>LQ>CX; and 4) stepwise regression analysis showed that contents of soluble sugar and MDA and ratio of Na⁺/K⁺ in leaves had a most significant influence on the total biomass, which could be used as a reference parameter for evaluating of saline tolerance of Camptotheca acuminata.

Key words: Camptotheca acuminata, provenance, saline stress, saline tolerance, physiology and biochemistry