The Interspecific Relationship Of Leymus Chinensis And Phragmites Commumis Under Main Environmental Factors

Interaction among environmental factors commonly occurs in natural environments, but their influence on plant performance is not fully understood. Leymus chinensis and Phragmites communis are co-dominant grasses in both nutrient-poor and rich steppes in the Songnen Plains of northeastern China. A replacement experiment was conducted to test for significant interactive effects of light, nutrient availabilities and soil water on mean plant height, rhizome length, biomass allocation and growth. It was conducted along two-level irradiance and three-level nutrient availabilities combinations or along two-level irradiance and three-level soil water combinations. The results showed that:There were significant interactive effects of light availability, nutrient supply and soil water on relationships of the two species (L. chinensis and P. communis). Facilitation was found in these plant attributes for both species when grown in mixture compared with monoculture, especially at low nutrient and irradiance levels.Results in the experiment suggested that L. chinensis and P. communis demanded on different resource based on the value of Relative yield total (RYT) and Relative yield (RY) larger than 1 at poor irradiance and nutrient level. Coexistence could benefit the total yield of mixed experimental population because the competitive relationship could improve the utilizing efficiency of resource, or there was difference in space or time of utilizing resource for both species. There are difference strategies in competing light. P. communis grew taller and intercepted more light, while L. chinensis increased Relative leaf growth rate (LRGR), Leaf area rate (LAR) in order to get more lights.