油松白桦混交林中生化他感作用的生物测定

The Bioassay of Allelopathy in the Mixed Stands of Chinese Pine and Asian White Birch

该文对油松（ＰｉｎｕｓｔａｂｕｌａｅｆｏｒｍｉｓＣａｒｒ．）、白桦（Ｂｅｔｕｌａｐｌａｔｙｐｈｙｌｌａ）混交林中的生化他感作用进行了生物测定。结果表明，油松白桦纯林及混交林中枯落叶、半分解枯落叶和表层土壤的水浸液、白桦鲜叶和鲜根的淋洗液及白桦根系的春季伤流液对植物幼苗生长均有一定的影响。所有样品均表现出在高浓度下显著抑制植物生长，随着浓度降低，抑制作用减弱、消失，甚至转变为促进作用的规律；其中各林分枯落叶水浸液及白桦鲜叶淋洗液在高浓度时抑制作用最强，但混交林枯落叶抑制作用有所降低，且在低浓度下表现出明显的促进作用。说明在营造松桦混交林时，白桦比例适当减小将有利于油松的生长。

The allelopathy in the mixed stands of Chinese pine(Pinus tabulaeformis)and Asian white birch(Betula platyphylla) is studied.Bioassay of leachates of leaf litter, half decaying leaf litter and surface layer soil under pine-birch mixed stand and each pure stand, bioassay of birch root spring bleeding and leachates of birch fresh leaves and fresh root,and field tests of some samples indicate that, the allelopathy effects of all samples on vegetable and pine seedlings do exist.In high concentration of leachates,seed germination, root and stem growth of the seedlings are inhibited significantly, with the concentration decreasing,inhibitory effects get weak, disappear and even turn into stimulating effects. Among all the samples,the inhibitory effects of high concentration leachates of leaf litter under each stand and fresh birch leaf are the strongest, but the inhibitory effects of leaf litter under the mixed stand are lower than those under the two pure stands,and the stimulating effects are displayed. It clearly shows that,it will be beneficial for the growth of Chinese pine when the Asian white birch exists in the stands.This will provide the conditions for high yield.