Effects of Different NaCl Concentration on Growth, Photosynthesis and Ion Accumulation of Brazil Banana Seedling

摘要

After 10 days treatment with different concentration of NaCl by solution culture, changes of growth, photosynthesis and ion accumulation of Brazil banana seedlings were evaluated. The results showed that low concentration ( 5~20 mmol/L) NaCl treatments were propitious to promote growth of Brazil banana seedling by 120% at most. While those treatments with higher than 20 mmol/L NaCl showed inhibition of growth. Gs, Tr, Pn declined, along with increased Ci, indicated that decrease of Brazil banana leaves photosynthesis under salinity stress was mainly caused by the non-stomatal factor. The minimum increase of Na+ contents was found in leaves under NaCl treatment, showing a salt exclusion mechanism which ensured a higher K+/Na+ and Ca2-/Na+ ratio in leaves, reduced damage to leaf lamina. Taken together the above results, it is suggested that Brazil banana was thought to be a salt-sensitive plant, and its threshold salinity value was 20-30 mmol/L NaCl.