Introduction of Phosphoenolpyruvate Carboxylase Gene from Echinochloa crusgalli into Wheat Mediated by Agrobacterium tumefaciens Characteristics of Drought Tolerance in ppc Overexpressed Rice Seedlings 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) Cloning and expression analysis on phosphoenolpyruvate carboxylase gene in Dendrobium officinale Alleviation of Drought Stress Inhibition on Photosynthesis by Over Expression of PEPC Gene in Rice CO2 Exchange and Chlorophyll Fluorescence of Phosphoenolpyruvate Carboxylase Transgenic Rice Pollen Lines Photosynthetic Pathway of Three Rattan Species in South China