Effect of shoot pruning and root removel on the subsequent growth in one-year-old mulberry tree.

Abstract

This experiment was carried out in order to make clear the relation between the growth state of mulberry tree at the pruning and subsequent growth. The one-year-old potted mulberry trees planted at certain intervals from May 15 to July 15 in 1963 were used as materials. They were divided into following two groups, the first group with new shoot which had grown after planting being pruned and the second one with new roots, in addition, being removed at the time of pruning. In both cases the increment of dry matter and distribution ratio of dry matter produced were expressed as the ratio of the increase in weight of each part to that of the total dry matter during a unit period. The results may be summarized as follows:
1) After pruning, the dry matter increment of new shoots in both cases differed depending on the growth state of plants at the pruning time, i. e., the increment of July 15 planting was the largest and that of June 25 planting was the smallest in all cases.
2) At first, the weight of root and stock were decreased for several weeks after the pruning. And the time of recovery to the weight of initial level were differed depending onthe growth state of plants at the pruning time.
3) In the case of root removal at the pruning time, new roots developed within 1-2 weeks from the root stocks. When the pruning and root removal coincided with the time of the least weight of stocks after planting, the regrowth of new root was least of all.
4) Generally the dry matter increment in plants with root removal were smaller than in plants with no root removal, and this tendency was most remarkable in the case of May 15 and June 5 planting.