Characterization Of The Flowering And Fruit Set Of Sweet Cherry In Greenhouse

Growing sweet cherry in greenhouse has good prospects.Three experiments about the effects of temperature adjustments in dormant period on the date of bloom and maturity of sweet cherry in greenhouse,the law of flower and fruit drop of sweet cherry,the microscopic observation of the developing process of gynoecial and androecial gametophyte were conducted.The main results were as followed:1.Through 35d(Nov,18～Dec,23,2004) temperature adjustments the chilling unit(CU)in treated greenhouse accumulated up to 681.2,were 42.0%higher than the control;Experiments in three consecutive years(2002～2004)showed that the date of budburst,bloom and maturity of sweet cherry in the treated greenhouse was 2～4d,5～9d and 6～8d earlier than the control respectively.Both results above proved the accelerating effects of temperature adjustment in breaking the dormancy of sweet cherry in greenhouse.2.No matter grown in the greenhouse or open field,there were one peak of flower dropping and two peaks of fruit dropping occurred to the sweet cherry.The peak of flower dropping,the 1^st and 2^nd fruit dropping was around 8d,16d and 24d after the bloom respectively.However comparing to the open field the flowers of sweet cherry in greenhouse dropped more seriously.3.The microscopic observation on the developing process of reproductive organ showed that:The occurrence of androecial tetrad of sweet cherry grown in open field was at 21d before anthesis(budburst stage),but for the greenhouse the date was 14d before anthesis(white bud stage);The appearance of ovule primordia of sweet cherry was at 35d before anthesis, and the development of ovule and embryo sac was completed before anthesis no matter grown in greenhouse or open field.However in contrast to open field there were more serious abnormality and abortion in the pollen,ovule and embryo sac in the sweet cherry in greenhouse.The higher temperature comparing to the open field was the possible cause for the abnormality and abortion in the reproductive organ of sweet cherry in greenhouse.The abnormality and abortion in the reproductive organ was the direct cause that lead to the serious flower dropping of sweet cherry in greenhouse.Experiments above may have significance in improving the cultivation technology of sweet cherry in greenhouse.