杏花芽分化期芽和叶片核酸含量的变化

Dynamic Changes of Nucleic Acid Contents of Buds and Leaves During Flower Bud Differentiation in Apricot Trees

用摘叶法确定兰州大接杏从 6月初至 7月 10日左右为花芽生理分化期 ,7月中旬开始进入形态分化。整个分化期芽中DNA含量变化呈双峰曲线 ,第 1个高峰在生理分化后期 ,第 2个高峰出现在大部分雌蕊、雄蕊进入分化时 ;RNA/DNA比值也呈双峰曲线 ,两个高峰出现的时间恰在DNA两次高峰出现之前 ;RNA和总核酸含量变化趋势相同 ,生理分化期持续上升 ,果实成熟前短时下降 ,进入形态分化期后快速增加 ,并保持高水平。叶片中DNA含量在生理分化期增加并在后期出现高峰 ,RNA/DNA比值一直下降 ;形态分化期总核酸、DNA、RNA含量和RNA/DNA比值的变化与芽内同期变化趋势相似。

The experimental results showed that the stage of physiological differentiation of flower bud in apricot trees was from early June to about 10,July and the morphological differentiation begun after the middle ten days of July.The changes of DNA contents in buds took on double peak curve and the first peak occurred at the later period of physiological differentiation and the second at the period when most of stamen and pistil had started differentiation.The ratio of RNA/DNA took on double peak curve as well which occurred just before two DNA peaks appearing.The changes of total nucleic acid contents were similar to the RNA contents which increased gradually during physiological differentiation,declined shortly before fruit ripening and increased sharply at the stage of morphological diffe rentiation. In leaves,DNA contents increased gradually during the period of physiological differentiation and showed a peak at the later.The ratio of RNA/DNA decreased continously at the same period.The changes of total nucleic acid,DNA,RNA contents and the ratio of RNA/DNA in leaves at the stage of morphological differentiation were similar to those in buds at the same period.