Phenotypic Variations of Exsiccate-specimen of Malus baccata (L.) Borkh. MbNramp1 Gene Cloning,Sequence Analysis and Expression Analysis in Malus baccata(L.)Borkh. Growth responses of four northern broadleaved tree species to soil Cd stress Effects of Low-temperature on Enzymes Activities of Nitrogen Metabollism and Free Amino Acids Contents in Root of Malus baccata Borkh. and Malus hupehensis Rehd. Seedlings Effects of Low-temperature on Enzymes Activities of Nitrogen Metabollism and Free Amino Acids Contents in Root of Malus baccata Borkh. and Malus hupehensis Rehd. Seedlings Effects of Cool and Cold Conditions on Nitrogen Uptake Kinetics in Malus baccata Borkh. Seedlings MbNramp1 Gene Cloning,Sequence Analysis and Expression Analysis in Malus baccata(L.)Borkh. Effects of Cool and Cold Conditions on Nitrogen Uptake Kinetics in Malus baccata Borkh. Seedlings Studies on Geographical Regions and Analysis on Genesis Through Natural Population of ‘Malus baccata (L.) Borkh’ in North-east of China RESEARCH OF Agrobacterium tumefaciens MEDIATED GENETIC TRANSFORMATION OF Malus baccata BORKH