苹果幼树秋季^14C同化物贮藏及再利用

本试验研究了苹果幼树不同形态~(14)C同化物的贮备特点、季节变化及再利用特性。结果表明,1.苹果碳素同化物贮藏形式有淀粉、糖、氨基酸和有机酸。淀粉秋季先在根中积累,贮备前期(9月)达到高峰,枝干木质部于休眠前(12月)、韧皮部于萌芽前分别达到高峰;糖和有机酸落叶前枝干中较多、休眠期以根系贮藏为主;氨基酸仲秋(9月)开始在根中积累、而不再上运;落叶回流氮化物主要贮藏在枝干中。2.萌芽展叶主要利用枝干贮藏营养,早春新根生长为根系贮藏营养第一个分配中心,枝叶旺盛生长为其第二分配中心。3.根系贮藏碳素营养春季极少以糖形式直接供应地上部,首先在根中转化成氨基酸,经木质部上运并在其中脱氨形成有机酸,大部分用于能量消耗,一部分再生成糖供新器官结构建造。

STUDIES ON THE CHARACTERS OF STORAGE METABOLISM AND REUSE OF ~(14)C-ASSIMILATES SYNTHESIZED IN AUTUMN IN YOUNG APPLE TREES

The accumulation seasonal variation and utilization of ~(14)C-reserves in pot-cultured young'Liao Fu'apple trees were studied during 1986 -1987. Tt was found that, in autumn, the storage process of various forms of ~(14)C-assimilates are different. Starch first accumulatied in roots, reached the maximum content in the middle-autumn and decreased rapidly after that. In the shoots and trunk, starch mainly accumulatied in xylem in late autumn, but transfered from it to the pholem by following early spring, so the maximum content of starch in the xylem was during dormant in the pholem before sprouting. Soluble sugar and organic acids mainly accumulatied in shoots and trunk before defoliation in autumn and mainly in roots during dormant. Amino acids formed inroots began accumulation in the middle-autumn in itselves, arid that returned from the leaves mainly storaged in shoots and trunk. fn spring, the sprouting of the trees mainly used the top storage nutrients, but the new roots and shoots vigorous growth mainly the root storage nutrients. The carbon reserves in roots didn't straigtly transport up to the top organs with the froms of soluble sugar and starch, but transformed that into amino acids, then translocated to the top through the xytem. These amino acids transformed into organic acids in the xylem of the old top parts, which were mainly used up in respiration but a little part formed new organs.