A STUDY ON INFRASPECIFIC TYPES OF CHEMICAL CHARACTER OF CINNAMOMUM SEPTENTRIONALE New Resource Plants of Trans-Methyl Iso-eugenoI from Endemic Species to China Study on Photosynthesis and Water Physiology of Cinnamomum septentrionale Effects of leaf litter of Cinnamomum septentrionale on growth and resistance physiology of Brassica rapa in the decomposition process of litter