THE EFFECT OF LIGHT INTENSITY AND PINCHING OFF INFLORESCENCES ON PHOTOSYNTHETIC RATE AND DISTRIBUTION OF ASSIMILATES OF AMERICAN GINSENG REGULATING EFFECT OF DENSITY AND TOP-DRESSING TIME OF NITROGEN FERTILIZER ON ~(14 ) C-ASSIMILATION AND DISTRIBUTION OF ASSIMILATE OF LARGE-SPIKE CULTIVAR OF WHEAT Cytochemieal Observation on Garlic Clove before and after Temperature-Modulated Break of Dormancy