COMPARISON OF THE NET PHOTOSYNTHESIS RATE OF FOUR POPLAR CLONES AT DIFFERENT TEMPERATURE AND HUMIDITY REGIMES Genetical Engineered Male Sterile Tobacco Plants and Their Sensitivity to Temperature Cytochemieal Observation on Garlic Clove before and after Temperature-Modulated Break of Dormancy Development of Sexual Organs in Taihangia rupestris--Different Temperature Requirments for Both Sexual Organ Development in a Bisexual Flower