<正>将初步鉴定为隶属于兰科丝核菌类瘤菌根菌属Epulorhiza sp的GDB254和角菌根菌属Ceralorhiza sp．的MLX102、CLN103真菌菌株接种到铁皮石斛组培苗，65d后测定对铁皮石斛生长均有明显的促进作用，接菌苗的平均鲜重净增率均高于对照，且经检验接菌苗与对照均达极显著差异α=0.01。叶绿素a、b含量也较对照有明显增加，其中GDB254菌株接种铁皮石斛后其叶绿素a、b含量分别增加76.2％、128.0％，MLX102使其增加84.9％、85.4％，CLN103使其增加57.9％、77.8％。通过徒手切片光学显微镜观察菌根，菌根真菌先在根外聚集并通过破坏根被入侵到皮层组织，在皮层组织细胞中通过菌丝穿越细胞壁不断延伸扩展，可侵染到中柱组织，并可在皮层和中柱细胞形成典型的菌丝结结构。从铁皮石斛生长量和叶绿素含量增加及根的显微结构表明，3个菌株确与铁皮石斛形成了共生菌根，并对其生长有明显促进作用。

To rich tree genetic resources in hot dry river valley region, the nine species and one clone of Casuarina were introduced to Yuanmou county, Yunnan province in 2003. The two field trials were established on July 8, 2007, the Casuarina introduction trial with six Casuarina species and one clone A8, and the inoculation Frankia trial for Casuarina cunnighamiana with four Frankia inoculation treatments and one control. A complete randomized block design was employed in the two trials, respectively with four replicates and 30 trees per seedlot in the introduction trial, and four replicates and 20 trees per Frankia treatment in the inoculating Frankia trial. At one and two years after planting, tree heights and survival percentages of Casuarina were recorded for the two field trials. The results showed that Casuarina equisetifolia, C. cunninghamiana and C. obesa gained the best height growth, and C. glauca presented poorest height growth in the six species and one clone in the field trials. Casuarina equisetifolia could be applied to hot-dry valley for further extensive use according to the field experimental results. Based on the experimental results, C. cunninghamiana inoculated with some Frankia isolates showed very significant differences in tree height.