Effects of Salt Stress on Photosynthetic Pigments and Activity of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase in Kalidium foliatum

The effects of NaCl and Na2SO4 on photosynthetic pigments, malondialdehyde (MDA), Rubisco activity and superoxide dismutase (SOD) activity were investigated in Kalidium foliatum (Pall.) Moq., which is distributed in the saline soil of Hetao irrigation area in Inner Mongolia China. The K. foliatum plants were treated with NaCl (0, 100, 250, 400 and 500 mM), Na2SO4 (0, 100, 250, 400 and 500 mM) and NaCl + Na2SO4 (1: 1, v/v) (0, 100, 250, 400 and 500 mM of Na+ concentration, 0, 50, 125, 200 and 250 mM of Cl- and SO (4) (2-) concentration) for 10 days. Content of chlorophylls and carotenoids were significantly higher than control at increasing NaCl and Na2SO4 concentration, in contrast, were significantly reduced by higher concentration of NaCl + Na2SO4. Rubisco activity reduced steadily at 100 and 250 mM NaCl, while increased at 400 and 500 mM NaCl. Rubisco activity was significantly higher than control at 100 mM Na2SO4, and was no more change under NaCl + Na2SO4 treatment. The SOD activity increased with increasing NaCl and Na2SO4, and increased at moderate NaCl + Na2SO4 treatment. MDA content was lower than control at 250 mM salt concentration. On the basis of the data obtained, K. foliatum showed resistance to salt such as Na+, Cl(-)and SO (4) (2-) , Rubisco activity in K. foliatum might be more sensitive to salt.