北方主要落叶果树对在土壤中施用不同量的PP333的反应

对苹果、桃、樱桃和葡萄进行了盆栽土施不同剂量PP333的试验。结果表,由于PP333在植物体内移动缓慢,PP333的抑制效果不能立即表现出来。PP333在植物体内的移动速度在苹果中较慢,在桃和樱桃中较快,葡萄介乎二者之间。 PP333对加长生长的抑制作用主要表现为节间的缩短和较早地停止生长,以及由此产生的节位数的减少。此外还表现在茎粗,单叶面积,叶片总面积,茎及叶的鲜,干重的降低以及副梢数目的减少和长度的降低上。PP333对根系也有抑制作用,但比地上部小,从而改变了根/冠比。土施PP333 1.0ppm以上的剂量有强烈的抑制作用,PP333抑制生长的强度与使用的浓度呈指数曲线相关关系。PP333促使新老叶片加厚。

RESPONSES OF SOME MAIN DECIDUOUS FRUIT TREE SPECIES TO THE SOIL APPLIED PP333 IN DIFFERENT DOSES

Experiments were conducted on potted apple, peach,cherry and grapevine nursery trees with different dose of paclobutrazol by soil application. Results showed that due to the low rate of movement there was always adelay between the time of application and the exhibition of growth effects. The velocity was lower in apple, higher in stone fruits, intermediate in grapevine.The inhibitory effect of paclobutrazol on growth of fruit trees expressed substantially on the shortening of the internode of the stem and the earlierter mination of growth and thus the less number of the internode. Further, it reduced the stem diameter, mean single leaf area, total leaf area, the dry and fresh weight of stem and leaf, and induced less number and shorter second flushes. Paclobutrazol also depressed root growth but it was negligible when compared with above ground parts. So that the root/stem ratio was greatly increased in favorable to reproduction. Paclobutrazol thickened not only the newly expanding leaves appeard after application, but also the leaves expanded before paelobutrazol being applied.Dose of paclobutrazol above 1 mg~(1~(-1)) strongly inhibited growth of fruit treess.The pattern of response to dose applied was best fit by an exponential curve.