紫茎泽兰和黄顶菊入侵对土壤微生物群落结构和旱稻生长的影响

为比较入侵植物与本地植物对土壤微生态影响的差异, 探索外来植物入侵的土壤微生物学机制, 本研究通过同质园试验, 比较分析了2种入侵菊科植物(紫茎泽兰、黄顶菊)和2种本地植物(马唐、猪毛菜)对土壤肥力和微生物群落的影响, 并通过盆栽反馈试验验证入侵植物改变后的土壤微生物对本地植物旱稻生长的反馈作用。同质园试验结果表明: 2种入侵植物和2种本地植物分别对土壤微生态产生了不同的影响, 尤其是紫茎泽兰显著提高了土壤有效氮、有效磷和有效钾含量，紫茎泽兰根际土壤中有效氮含量为39.80 mg·kg^-1，有效磷含量为48.52 mg·kg^-1。磷脂脂肪酸指纹图谱结果表明, 2种入侵植物与2种本地植物相比, 较显著增加了土壤中放线菌数量, 而紫茎泽兰比其他3种植物显著增加了细菌和真菌数量。盆栽结果表明: 黄顶菊生长过的土壤灭菌后比灭菌前旱稻株高增加113%, 紫茎泽兰也使旱稻的株高增加17%。由以上结果可知, 紫茎泽兰和黄顶菊可能通过改变入侵地土壤的微环境, 形成利于其自身生长扩散的微生态环境从而实现其成功入侵。

Effect of Ageratina adenophora (Spreng.) and Flaveria bidentis (Linn.) invasion on soil microbial community and Oryza sativa L. growth

This study analyzed the differences in soil micro-ecology between alien invasive weeds and local plants to understand impacts of alien invasive plant on soil ecosystem. Two invasive plant species perennial Ageratina adenophora (Sprengel) and annual Flaveria bidentis plants] and two native plant species (Digitaria sanguinalis and Salsola collina) were planted in a common garden, in which the same soil from a non-invaded farmland was used to eliminate the effect of different soil minerals on the variations in the four plant species. Then a greenhouse experiment was conducted to verify any effects of rhizospheric soil microbial communities of two invasive plants on the performance of native plants. In the field experiment, soil nutrient, soil microbial community after three months of plants growth were examined. Based on the common garden experiment, differences were noted in the effects of invasive and native plants on soil micro-ecology. A. adenophora drastically increased soil available N (39.80 mg·kg^-1), P (48.52 mg·kg^-1) and K. In particular, PLFA (phospholipids fatty acids) fingerprint spectrum suggested a higher increase in actinomycete contend in the exotic plants soils than in the native plants soils. The increase in bacteria and fungi count was highest in A. adenophora invading soils. Pot feedback experiment showed that alien weed invaded soils inhibited the growth of Oryza sativa. O. sativa plant height increased by 113% and 17% in ste-rilized F. bidentis and A. adenophora invaded soils compared with no-sterilized soils, respectively. The above results suggested that F. bidentis and A. adenophora destroyed micro-habitats of invaded soils and created new micro-ecology environment suitable for the growth of invasive plants by altering soil microbial communities.