梓树苗木地下和地上竞争的效应研究

Research of Below and Above-ground Competitions in Catalpa ovata Seedlings

采用生物量计算的竞争指数和通径分析的方法,研究了3种密度的梓树苗木地下竞争和地上竞争的关系及对总竞争的影响。结果显示,梓树苗木地下生物量、地上生物量和总生物量与密度密切相关,随着密度的增加,其根、茎、叶的生物量减少,根冠比均小于1。在同一密度条件下,地上竞争指数明显大于地下竞争指数,地上竞争对总竞争的直接作用范围(0.449 3～0.973 1)明显大于地下竞争对总竞争的直接作用(0.275 6～0.773 2)。研究表明,梓树幼苗地上茎、叶的竞争在梓树苗木总的竞争中占有重要地位。

An experiment was conducted by the methods of path analysis and competition index based on bi- omass, to study the impact of different planting density of Catalpa ovata seedling above-ground and below- ground competition to general competition. The result showed that there were close relationship among a- bove-ground biomass,below-ground biomass and total biomass,with the density increased the biomass of root,shoot and leaves decreased and the ratio value of above-ground biomass with below-ground biomass was lower than 1. Above-ground competition was obviously larger than below-ground competition under the same density. The direct effect of above-ground competition on general-competition was from 0. 449 3 to 0. 973 1 ,which was obviously larger than below-ground competition on general-competition （0. 275 6～ 0. 773 2）. Shoot and leaves of C. ovataseedling competition play an important role in general-competition.