<正>以15个不同地区百年左右的银杏雄树花粉为材料，用高效液相色谱法（HPLC）检测了银杏花粉中黄酮和内酯的含量。结果表明：银杏花粉主要含有以山奈素为母核的黄酮醇苷。以槲皮素和异鼠李素为母核的黄酮苷的含量相对较少?银杏花粉总黄酮含量平均为20.44mg/g；还发现银杏花粉中的内酯成分为银杏内酯A，其含量平均在2.22mg/g；不同地区间银杏花粉之间的黄酮和内酯含量差异显著。相关分析表明，不同地-区银杏花粉之间黄酮和内酯含量的差异与气候地理因7的相关性不显著。初步筛选出黄酮和内酯含量较高的重庆01、广德01、北京01、康县0J等4个单株作为备选的优良单株。

Soil enzyme activities and the relationships with soil physical, chemical properties and microbial biomass of eight, typical plots in representative semi-arid areas, were discussed. The results shown that soil enzyme activities were not so high in this region {or shortage o{ moisture and high soil salt content. The trends of soil enzyme activities in the same profile were very similar. Correlation analyses also shown the soil enzymes were affected by respectively soil physical, chemical and biological properties. Especially the organic matter content and microbial biomass have a very closed relationship with many enzymes. The regression equations between soil enzyme activities and chemical properties were obtained by using a stepwise regression method. The principal component analysis reflects that the microbial biomass and the neutral phosphatase have higher coefficient in every major constituents, so these two properties can be considered to be the most important soil biological factors. Finally, the cluster analysis by soil enzyme activities and microbial biomass were conducted. The eight plots can be sorted to different degrees.