云南松根际pH与不同磷水平下云南松幼苗根际pH变化

通过滇中红壤区域现实林分中不同林龄云南松根际与非根际土的pH分析和不同磷处理水平下培养的云南松幼苗根际pH的测定，探讨了云南松根际pH以及不同磷水平下云南松幼苗根际pH变化。结果表明，低磷环境下云南松根际土和非根际土的pH值在3．49～3．79之间；云南松根际土pH明显低于非根际土，二者之间的差异极显著，但在不同林龄组间差异不明显；云南松幼苗能使根系周围pH下降，随着供磷水平的降低，云南松幼苗根系使根际pH降低的能力加强。本试验对云南松的研究结果与对其它一些树种进行研究所取得的结果有所不同，根际酸化是云南松适应低磷环境的有效反应之一。

Rhizosphere pH of Pinus yunnanensis Franch.and Rhizosphere pH of P.yunnanensis Seedlings at Different Phosphorous Rates

The rhizosphere pH value of Pinus yunnanensis Franch. in the P. yunnanensis forests at different ages of the stands located in the red-soil regions of central Yunnan province,and the rhizosphere pH value of P. yunnanensis seedlings treated with different phosphorus rates were measured to study rhizosphere pH of P. yunnanensis and rhizosphere pH value of P. yunnanensis seedlings fertilized at different phosphorous rates. The results showed the rhizosphere and non-rhizosphere pH value of P. yunnanensis ranged within 3. 49-3.79 under low-phosphorous circumstances;P, yunnanensis had a remarkably lower pH in its rhizosphere than that in its non-rhizosphere and the difference reached a extremely significant level,but there were insignificant differences among the rihizosphere pH value of P. yunnanensis in P. yunnanensis forests of different age groups;the P. yunnanensis seedlings could lower its rhizosphere pH and its pH-decreasing capacity increased with the phosphorous rates reduced. The results of this study about P. yunnanensis are different from the results of other studies about tree species other than P. yunnanensis to some extent and rhizosphere acidification is one of the effective responses of P. yunnanensis to low-phosphorous environments.