修剪与摘叶对苹果幼树吸收贮藏和再利用~(15)N的影响

1984年9月对苹果幼树根际或根外标记~(15)N-硫酸銨,1985年1月进行重修剪或轻修剪。翌年春梢旺长期间,两种标记~(15)N植株中重剪均比轻剪能更多地將贮藏~(15)N调运到地上部旺长中心;春梢停长后,仅根际标记~(15)N植株重剪大于轻剪。1984年9月19日摘除苹果幼树中、长梢的上半部或下半部叶片,次日标记~(15)N-硫銨酸銨。若根外标记,剩余的上半部叶片吸收~(15)N能力大于下半部叶片;若根际标记,摘下部叶处理对根系吸收~(15)N的抑制作用大于摘上部叶处理。翌春两种标~(15)N植株各摘叶处理贮藏~(15)N的再利用模式无显著差異。

EFFECTS OF PRUNING AND REMOVAL OF LEAVES ON ~(15)N ABSORPTION, STORAGE AND REUTILIZATION IN YOUNG APPLE TREES

1. Young apple trees (cv. Red Fuji-2 grafted on M. prunifolia Borkh.)were treated with soil or foliage application of ~(15)N-labelled ammoniumsulphate in September, 1984. Those trees were either pruned heavily orlightly in Janary, 1985. During the period of rapid shoot growth inspring, the capacity of transporting ~(15)N reserves to the new rapid growthof above ground parts by heavy pruning was greater than that by lightpruning in the trees with either soil or foliage application of ~(15)N. Afterthe growth of spring shoot ceased, the capacity of mobilizing ~(15)N reservesin heavy-pruned trees was still greater than that in light-pruned trees(noone but in the treatment of soil fertilization.) 2. The removal of the leaves on upper or lower parts of middle andlong vegetative growth shoots in young apple trees (cv. Rose Redgrafted on M. prunifolia Borkh.) was made on September 19, 1984. ~(15)N-ammonium sulphate was applied either to the remained leaves or to theroots on the following day. It was demonstrated that the amount of ~(15)Nabsorbed by the remained leaves on upper parts was more than that onlower parts. On the contrary, if ~(15)N was applied to the roots, thecapacity ~(15)N-root uptake would (?) much greater in the treat-ment of removing leaves on upper parts than that on lower parts. Thepattern of reutilization of ~(15)N reserves was not affected by the treatmentof removing leaves.