Ca~(2+) Regulation Function of Brassica Chinensis L. under Simulated Acid Rain Stress

By greenhouse cultivation,the responses of 6 kinds of different forms of calcium amount in the body as well as physiological and nutritional quality indexes to different calcium concentrations were studied under the stress of simulated acid rain on brassica chinensis L. The results showed that appropriate concentration of Ca2 +can increase the absorption of the different forms of calcium but high concentration decreased them,which signifies excessive calcium's concentration causes inhibition of absorption. The concentration of pectic acid calcium and tricalcium phosphate promote along with the increasing of concentration of total calcium,after reaching the peak,it begin to decrease,and the trend increasing is more significant under stronger acid rain stress. And total calcium concentration and its residue state increase,yet Inorganic calcium and water soluble calcium decrease. The content of soluble sugar and chlorophyll increased along with the growth of Ca2 +concentration,which indicates that Ca2 +has the positive effect of the resistance to acid rain in some extent. After the regulation of higher Ca2 +,the differences of soluble sugar and chlorophyll between under the stress of stronger acid rain and weaker were smaller,compared with the situation of lower Ca2 +,which suggested that appropriately increase the exogenous Ca2 +concentration will help to relieve the damage caused by stronger acid rain. Pectic acid calcium is able to enhance stiffness of cytoderm and maintain the stability of Cell membrane,which is one of fundamentals of protection against acid rain.