芦苇对空心莲子草从陆生环境向水生环境扩散的影响

目的]探讨芦苇种植对空心莲子草从陆生境向水生境扩散的影响。方法]模拟河岸带芦苇与空心莲子草生长状态，比较混种和控制条件下空心莲子草扩散及生物量变化。结果]与控制条件下相比，芦苇种植使空心莲子草在陆生境纵向（沿陆地向水中的方向）与横向（与纵向垂直）扩散日变化率显著下降（P〈0．05）；水生境中均未出现显著差异；陆生境中横向和纵向扩散符合指数生长模型：Y=ae^bx＋y0；根生物量显著下降，达到50％；茎生物量下降16％，但其占比却上升62％。结论]芦苇存在时，陆生境空心莲子草所受到的抑制要强于水生境；空心莲子草会通过提高其地上生物量占比，对芦苇抑制做出反应，以获取更多的光照。

Effects of Planting Phragmites australis on the Diffusion of Alternanthera philoxeroides from Riparian Place to Water

Objective ] The research aimed to test the effects of planting Phragmites auatralis on the diffusion of Alternanthera philoxeroides from riparian place to water. Method] P. australis with A. philoxeroldes under the condition that simulating the natural state of riparian zone using boxes were planted. The situations of diffusion and changes of biomass of them were investigated during the process of growing. Result ] The results indicated that interspecific competition showed great effects on the diffusion of A. philoxeroides in riparian place, but not in water. Compared to control treatment, the diurnal variation of lateral and longitudinal diffusion rate of A. philoxeroides decreased significantly（P 〈 0.05） in mixed treatment. Lateral and longitudinal diffusion of A. philoxeroides was in accordance with index growth model, y = ae^bx ＋ Y0. In addition, compared to control treatment, the total and stem biomass deceased by 50% and 16% in mixed treatment, respectively. But the stem mass fraction increased by 62%. Conclusion] In mixed treatment, P. australis showed greater negative effects in riparian place than in water on A. philoxeroides. And A. philoxeroides exhibited greater aboveground biomass for subsisting in competitive sites.