Growth responses of four northern broadleaved tree species to soil Cd stress Measuremen t of the Transpiration Rate of Developing Pear Fruit Pericarp Structure and Storage Quality of Pyrus ussuriensis Fruits Anatomical Study of Fruit Setting and Male and Female Gametophytes in Pyrus ussuriensis Year-round accumulation of dry matter and NPK of ‘Nanguo’ pear trees Pericarp Structure and Storage Quality of Pyrus ussuriensis Fruits Measuremen t of the Transpiration Rate of Developing Pear Fruit Analysis of Volatile Compounds of Pyrus ussuriensis‘Xiaoxiangshui’During Ripening Genetic Structure Analyses Based on Fluorescent-AFLP Markers of Wild Populations of Pyrus ussuriensis Maxim in Heilongjiang Provinc