云南松根际与非根际磷酸酶活性与磷的有效性

通过对采集自滇中红壤区域的不同林龄云南松的根际与非根际土，以及不同磷补充量下根袋法培养的距云南松幼苗不同距离土壤的磷酸酶和有效磷的测定，探讨了根际与非根际土的磷酸酶变化及其与有效磷之间的关系。云南松根际及非根际都含有大量的磷酸酶，且这些磷酸酶的活性在根际土中较高。酸性磷酸酶是云南松土壤中的主要酶类，中性磷酸酶次之。培养实验结果显示，无论是根际土、近根际土还是远根际土，外界补充的磷量越低，其酸性和中性磷酸酶的活性越高，反映出磷饥饿对磷酸酶的诱导。但磷酸酶的变化同土壤有效磷的相关性不显著。因而酶数量增加不是云南松对磷饥饿的唯一适应性机制，它的变化或许只是磷胁迫下的一种症状。

Soil phosphatase and P availability in rhizosphere and non-rhizosphere of Pinus yunnanensis

Soil phosphatase and available P of the rhizosphere and non-rhizosphere of Pinus yunnanensis with different ages in cen- tral part of Yunnan Province, and of different distance from P. yunnanensis seedlings under different P supply at the laboratory had been studied. There were large quantity of phosphatase distributed at the rhizosphere and non-rhizosphere of P. yunnanensis, among which acid phosphatase was the major one and followed by alkaline phosphatase. Result from the implantation of seedlings showed that, anywhere of the di stance from the seedling roots, the less the supply of P, the higher the amount of acid and alkaline phos- phatase, which implied that phosphatase can be induced by P starvation. The relationship between changes of phosphatase and changes of available P was not significant. So the increase of phosphatase was not a unique adoption mechanisms of P. yunnanensis under P starvation, it may be a symptom only.