Some factors affecting the rooting of softwood cuttings of Japanese persimmon

The factors influencing rooting of softwood cuttings of two cultivars,'Jiro ' and 'Nishimurawase', of Japanese persimmon (Diospyros kaki Thunb.) were s tudied. The cuttings from the root suckers of micropropagated trees rooted best, followed by those from the shoots of micropropagated trees and grafte d trees in that order. Except for the cuttings from grafted trees, the shor ter the cuttings, the higher the rooting percentage. When planted in late J une, the single bud, leafy cuttings (leaf-bud cuttings) taken from the root suckers and treated with indole - 3 - butyric acid (IBA), 70% or more root ed well. When planted in late July or late August, however, less than 40% o f the leaf - bud cuttings rooted. Comparable cuttings without IBA treatment scarcely rooted when planted in late June, and did not root at all when pl anted in late July or late August. There was no significant difference in t he rooting capacity between the two cultivars. Almost all leaf-bud cuttings from the root suckers survived during the experimental period (60 days), a lthough those from the shoots of grafted trees died gradually; none of the 25-cm cuttings from the root suckers survived 25 days after planting. The v ascular cambium at the base of leaf-bud cuttings from the root suckers bega n to divide actively soon after planting. Callus formed in the phloem and c ortex of the cut surface and developed extensively. However, active cell di vision was not observed at the bases of leaf-bud cuttings from the shoots o f grafted trees nor 25-cm cuttings from the root suckers. Initial cells of the adventitious root produced in the vascular cambium of the leaf-bud cutt ings from the root suckers were first observed 20 days after planting; they developed to roots and emerged 30 days after planting.