Shoot apex comparative morphology of Pinus yunnanensis and its closely related species under different habitats Late Embryogeny of Pinus bungeana ULTRASTRUCTURAL STUDY OF SHOOT APEX IN PAEONIA SUFFRUTICOSA ANDR. FROM VEGETATIVE GROWTH TO REPRODUCTIVE GROWTH An Ultrastructural Evalution of Cytohistological Zonation in the Shoot Apical Meristem of Torreya grandis Comprehensive Pattern of Primordium Initiation in Shoot Apex of Wheat Nicotine Concentration in Leaves of Flue-cured Tobacco Plants as Affected by Removal of the Shoot Apex and Lateral Buds A Study of Shoot Apex Grafting is in Vitro for Virus Elimination Citrus Shoot Apex Demand Determines Assimilate and Nutrients Partitioning and Nutrient-uptake Rate in Tobacco Plants Structural and Histochemical Studies of Vegetative Apex in Torreya grandis REGENERATION SYSTEM AND INFLUENCING FACTORS FOR GENETIC TRANSFORMATION OF SORGHUM SHOOT APEX