根癌病对几种樱桃砧木生长发育及氮、磷分配的影响

利用人工接种试验，研究了根癌病对几种生产中常用的樱桃砧木生长发育及氮、磷分配的影响效应，结果表明，根癌病菌能显著抑制新梢和茎干粗度的生长，并使树体叶绿素含量降低，导致树体光合速率下降，但下降幅度与树体抗性有关，树体抗性愈强，则下降幅度愈小；根癌病菌能促进患病植株的根系活力，根癌病菌导致的根系活力的升高促进冠瘿瘤的生长发育，但没有促进树体的生长。冠瘿瘤中，氮、磷含量明显高于该冠瘿瘤所着生的枝条；冠瘿瘤是强生长中心，发生在枝干上的冠瘿瘤首先与地上部协作，共同参与争夺地下部的磷素，然后再参与地上部磷素的竞争；根癌病首先干扰氮素由地上部向根部的回流，其次才影响氮素从叶片向树体其它部位的回流。

EFFECTS OF CROWN GALL ON THE VITALITY AND THE STATUS OF NITROGEN AND PHOSPHORUS OF SOME CHERRY ROOTSTOCKS

The effects of crown gall on shoot growth and the status of N and P of some cherry roodstocks were studed by inoculating experiment. The resuits showed that the growth of shoot length and stem diameter of infected rootstocks was reduced in late phase of crown gall occurrence. The more quickly the shoots grew, the more quickly the tumors occurred. This disease also affected content of leafy chlorophyll and Pn of plants. As for a rootstock, the stronger resistance to crown gall it had, the less content of leafy chlorophyll and Pn it would be decreased. Crown gall could promote root activity,which not resulted in growth increase of host and also in tumor growth. Consistently higher concentrations of N and P occurred in shoot tumors on potted cherry rootstocks compared to nontumorous shoot tissue. Tumor was one of the strongest growth center;the crown gall on shoots togethering with other parts above ground, could conyete at first for p with root, then take part in competition of P among parts above grownd. Crown gall interfered with nitrogen back flow from parts above ground to root system firstly, then affected nitrogen back flow from leaves to other parts of tree.