Growth and Physiological Responses of Taxodium mucronatum×Cryptomeria fortunei Under Different Salt Stress Conditions

Taking strong and consistent 2-year-old Taxodium mucronatum×Cryptomeria fortunei as material. By setting different concentrations of salt stress treatment, hydroponic method was used to analyze the seedling rate, shoot increment, chlorophyll content, malondialdehyde content, relative conductivity and superoxide dismutase. The salt tolerance and physiological changes under different degrees of salt stress were studied. Results show that there is no significant difference between CK and the 3‰ NaCl stress on the growth and physiology changes under 40 days treatment. At the 50^th day of the experiment, the growth of T. mucronatum×C. fortunei treated with 3‰ NaCl is slightly decreased. However, under the 6‰ NaCl stress, the growth of T. mucronatum×C. fortunei is significantly inhibited, and the seedling survival rate is significantly lower than that of CK and 3‰ NaCl stress. And chlorophyll content in leaves decreases significantly, MDA content and relative conductivity are significantly higher than those of CK, and the integrity of the cell membrane is destroyed to a certain extent. Thus, T. mucronatum×C. fortunei can resist low salt concentration 3‰ NaCl stress in a short period of time, but it can not eliminate the growth inhibition caused by 6‰ salt stress.