Abstract: Regulating effects of ecological factors such as planting density,fertilizer,water and photointensity on the yield-related traits in Maize were studied by the methods of combination of field-growth with pot-growth. The results are as follows:raising density can cause the decrease of chlorophyll content, leaf area and dry weight per plant. The effects of density and the interaction of density with fertilizer on the grain number per ear reached high significant levels(F=55.08 ^** ,F=70.30 ^** ). The effect of Pfertilizer is less than that of density(F=7.33 ^*). Grain weight and grain number per ear was reduced 44.66% and 52.32% under drought from silking to 6 days after silking respectivily. Abortive grains were increased 443.85% and 100-grain weight was decreased 21.81% from 12 to 17 days after silking.Photointensity on ear position and low leaf layer were correlated and regressed significantly to grain traits.

Key words: Dianchi Lake, wetland plant, degraded wetland, plant community, species invasion.