自然环境胁迫对旱冬瓜Frankia菌基因多样性的影响

利用rep-PCR方法，研究云南鸡足山及无量山不同生境下旱冬瓜根瘤内Frankia菌基因多样性及其变化，以了解不同自然环境胁迫对Frankia菌基因多样性的影响。结果表明，多样性随地域、海拔和坡向不同而变化，鸡足山Frankia菌基因类型比无量山丰富。鸡足山旱冬瓜根瘤内的Frankia菌在山底2300m处，Shannon指数平均为0．90；山顶海拔2650m以上，Shannon指数随之上升到1．33。南坡Frankia菌多样性高于北坡，表明多样性指数与环境胁迫大小成正相关，自然环境胁迫是产生和保持Frankia菌基因多样性的重要因子之一。

Effect of natural stress on genetic diversity of Frankia in Alnus nodules

The genetic diversity of Frankia in the nodules of Alnus nepalensis growing in different habitats of Jizu and Wuliang Mountains in Yunnan Province was studied by rep-PCR technique. The results indicated that the Frankia had an abundant genetic diversity, which was varied with different zones, altitudes and slopes. More genotypes of Alnus-infective Frankia were found:at Jizu than at Wuliang Mountain. At the bottom of Jizu Mountain (2 300 m), the Shannon-Weiner index was 0.90, and increased with raising altitude, up to 1.33 at the top (2 700m). The genetic diversity of Frankia was more abundant along the southern slope than the northern slope. It was concluded that the diversity index was positively related to natural stresses which were one of the important factors producing and maintaining the genetic diversity of Frankia .