紫茎泽兰种子种群动态及萌发特性

在紫茎泽兰的入侵地四川省德昌县, 选择撂荒地、农田和马尾松林3个不同的生境, 从种子雨、种子库角度研究了紫茎泽兰种子种群动态规律，及其种子在不同光照和土壤基质条件下的萌发特性. 结果表明，3个生境下紫茎泽兰种子种群仅存在于当年3～6月，于4月底达到年高峰值. 其年降种子雨量在撂荒地中高达2.4×10⁵粒·m^-2，并均分布于2 cm土层以上, 且在撂荒地生境下紫茎泽兰种子的千粒重和活力均显著高于另外两个生境. 到7月上旬, 3个生境下土壤中均未发现有活力的种子. 在实验的光照条件下, 全光照对紫茎泽兰的种子萌发有抑制作用，而在28%光照条件下萌发率最高；砂壤土较适宜紫茎泽兰种子的萌发，生红土中其萌发速度及萌发率均最低.

Seed population dynamics and germination characteristics of Eupatorium adenophorum

With bare land, farmland, and masson pine forestland in the Eupatorium adenophorum- invaded area of Dechang County, Sichuan Province as test habitats, this paper studied the seed population dynamics of E. adenophorum at the levels of seed rain and seed bank, and its seed germination characteristics under effects of light and soil medium. The results showed that in the three habitats, the seed population of E. adenophorum only existed from March to June, and reached its peak by the end of April. The annual seed rainfall in bare land habitat amounted to 2.4 x 10(5) individuals per square meter, and all the seeds were distributed in the soil layer above 2 cm. The thousand seed weight and seed activity of E. adenophorum in bare land habitat were significantly higher than those in another two habitats. No active seed was found in the three habitats by the first ten days of July. Under artificial light condition, full light had some inhibitory effects on seed germination, while 28% of full light gave the highest germination rate. Sandy loam soil was more favorable for the seed germination, while in un-reclaimed red soil, both the germination velocity and germination rate were the lowest.