Studies on the sexual organ development and fruiting characteristics of different varieties of apricot Armeniaca vulgaris Diurnal Variation of Photosynthesis and Relationship with the Eco-physiologcal Factors in the West of Tianshan Mountains CRYOPRESERVATION OFAPRICOT CALLI THE DEVELOPMENTAL AND ANATOMICAL STUDIES ON THE FLORAL NECTARY IN ARMENIACA VULGARIS LAM