Cloning of Citrate Synthase Gene in Rapeseed(Brassica napus L.) and Its Expression under Stresses Cloning of tobacco citrate synthase cDNA and construction of its light inducible plant expression vector Organic acid metabolism in nectarine fruit development under protected cultivation Changes of Organic Acid Synthetase Activity during Fruit Development of Navel Orange (Citrus sinesis Osbeck) Changes of Organic Acid Synthetase Activity during Fruit Development of Navel Orange (Citrus sinesis Osbeck)