Effect of Na2CO3 Stress on Growth and Physiological Properties of Diospyros japonica Seedlings

In May 2019, 2-year Diospyros japonica seedlings were selected from Hunan Forest Botanical Garden for ball transplanting in pot. Slow rooting was carried out for 2 weeks. Experiment was implemented on Na2CO3 stress on these seedlings with 1 g/L, 2 g/L, 4 g/L, 6 g/L and 8 g/L, and water as control. On the 8th, 16th, 24th and 32nd day, the growth and physiological properties of seedlings were determined to study its salt tolerance. The results showed that height and ground diameter growth of treated seedlings increased first and then decreased with the increase of Na2CO3 concentration, the relative water content in leaves decreased obviously. With duration of stress and the increase of Na2CO3 concentration, MDA content of treated seedlings increased; the activities of peroxidase and superoxide dismutase both increased to reduce oxidative damage. Treated seedlings could accumulate a large amount of osmoregulation substances (soluble protein and soluble sugar) to keep its osmotic potential. The conclusion revealed that D. japonica seedlings treated by 1-4 g/L Na2CO3 had resistance, but that by 6g/Land 8g/L got damaged.