Effects of Salt Stress on Growth and Photosynthetic Characteristics of Carya Illinoemis

The potted one-year old seedlings of Carya illinoensis have been used to study the effect of salt stress on growth and photosynthetic characteristics.And the growth,survival rate and photosynthesis are determined by the treatment of different NaCl concentration with 0,0.1%,0.2%,0.3%,0.4%,0.5%,0.6%,0.7% and 0.8%,respectively.The results show that there is no significant effect of 0.1% NaCl concentration on the growth and photosynthesis of Carya illinoensis seedlings.While the growth and photosynthesis are significantly decreased when the NaCl concentration was over 0.2%,and the higher the NaCl concentration is,the lower the growth and photosynthesis show.The growth of pecan seedlings almost ceased and the photosynthesis became quite weak under the treatment of NaCl concentration over 0.7%.And the survival rate dropped to 22.2%,even lower.In addition,the stomatal limitation might be the main factor restricted the photosynthesis under the treatment of lower NaCl concentration(≤0.4%),while the higher NaCl concentration(0.4%) affected the photosynthesis usually by non-stomatal limitation factor.