Study On Soil Factors In Flaveria Bidentis Invasion Region And F. Bidentis Symbiosis With AM Fungi

Flaveria bidentis is an invasive plant that spread in Hebei in the recent years widely, has very strong invasiveness and serious threat to ecosystem, environment and agricultural production of invasion area. The most of searches on F. bidentis are about prevention, control and eradication currently, the studies on invasion mechanism have focused on allelopathy and physiological and ecological characteristics, but mostly in laboratory studies, the study carried out under natural conditions is little. This paper studies the change of soil factors before and after invasion and colonization and distribution of AM fungi in the rhizosphere of F. bidentis by field investigations and analysis in major F. bidentis invasion region in Hebei, so as to provide the bases for ascertaining invasion mechanisms to prevent and control F. bidentis spread. Main results are as follows:1. The soil of F. bidentis invasion area is alkaline and has a wide range of nutrients content from low to high.2. The effect of F. bidentis invasion on soil pH is different among sites, the effect on soil factors relating to soil nutrient levels in invasion area, and when at a low level, the F. bidentis invasion increases content of soil nutrient, when at a high level, then lowers soil nutrients, the F. bidentis could gather nutriens while it grows in low nutrients level soil.3. The impact of F. bidentis invasion on the soil is affected by the distance among sites, the further distance among sites, the more different effect, so the impact of F. bidentis invasion on the soil is closely related to environmental conditions.4. F. bidentis could form very symbiosis with AM fungi. Soil factors has little effect on the growth of AM fungal hyphae in the rhizosphere of F. bidentis, but the growth and development of AM fungal vesicles, arbuscules and spores in the rhizosphere of F. bidentis was closely associated with soil factors.