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Pollination and fertilization were studied in two 'seedless grapevine cvs, White Seedless and Askary using 15 year - old vines in Shahriar area. Vines were sprayed in whole by Boron at 0, 1500,3000 mgL-1 10 days before flower opening. Flower san1ples were collected 24 and 48 hours after flower opening. Samples were fixed in Carnoy's fluid and prepared for microscopic observation by ultra violet light. Boron showed its significant effect on pollen germination
on stigma, pollen tube growth in style and lower part of ovary. The number of
penetrated ovules by pollen tube were also increased by boron application. The effect of boron application at 3000 mgL-1 was much more effective than its lower concentration i. e. 1500 mgL-I. Boron could increase fruit _ set percentage in both cvs. However, it was significant just in White Seedless but not in Askary. Total soluble solid, acidity and berry size were affected by Boron, though not at a significant level. Key