PRELIMINARY STUDY OF CO2 FLUX OF A LARCH FOREST BY EDDYCOVARIANCE AND ECOPHYSI OLOGICAL METHODS Soil Amelioration of Saline-alkali Lands Influences on the Pigments and C4-Photosynthesis Related Enzymes in Leaf, Bark and Branch Chlorenchyma of Yinzhong Poplar Macronutrients and their allocations in non-photosynthetic organs in the Picea balfouriana in western Sichuan Photosynthetic characteristics of the non-photosynthetic organs of Mikania micrantha and its ecological significance