Dynamics Population Occurrence And Plant Vicarious Of New Invasive Plant Flaveria Bidentis

The large-scale diffusion of Yellow top weed(Flaveria bidentis(L.)Kuntze)has a potential threat to the place of economic and ecological. In this experiment, different years bidentis seed emergence, plant growth and development at a continuous survey. And use symbiosis plant of bidentis’s root, stem and leaf water extract to cultivate its seeds. The research on occurrence of dynamic and vicarious species plants in the early period invasion of bidentis. The main results were as follows:1. Bidentis seeds are began emergence in late April under natural conditions, bidentis cell emergence of dynamic stabilized in late July, bidentis seeds of artificial humidification is emergence early than natural rainfall for one week. Natural rainfall treatment the number of emergence could up to 45,000/m2, artificial humidification treatment the number of emergence could up to 550,000/m2, Artificial humidification bidentis population density is 10 times to natural rainfall. Population density has effect to bidentis plant growth. The final population density of bidentis is 25/m2 in 2009.The final population density of bidentis is 100/m2 in 2010. seeds emergence when the 5th slide temperature > 15°C, A large number of emergence when the 5th slide temperature > 20°C, the two indicators can be used as the criterion for the prediction of the rate of emergence of the field bidentis.2. The density can effect plant height and leaf number distribution of bidentis. Bidentis’s plant height decreases with the increase of population density, the number of trunk and leaves decrease with the increase of population density. more than 50% of bidentis’s plant height distribution between 150~199.5cm, And 99.5% of plant height are more than 60cm in 2009, but bidentis’s plant height distribution between 60~99.5cm is 47.4%, plant height above 150cm accounted for only 1.1% of the total number of plants in 2010. Bidentis trunk leaf distribution in more than 10 pairs accounted for 100.0% of the total in 2009. Bidentis trunk leaf distribution in more than 10 pairs accounted for 96.5% of the total in 2010.3. Cumulative trunk budding rate of bidentis from 5% to 95% lasted the same as the 20 day. Cumulative trunk blooming rate of bidentis from 5% to 95% lasted the same as the 25 day. Thus, the change of bidentis population density did not affect the budding and blooming of bidentis. We can be based on this indicator control bidentis. 4. The research on plant vicarious species of bidentis found that, Erigeron canadensis L.,Euphorbia hyssopifolia Linn.And Setaira viridis(L.). Different concentrations of extracts of roots, stems and leaves have varying degrees of difference with contrast to Flaveria seed germination rate. 5%、10% root extract of Erigeron canadensis L.;1%、5%、10% stem extract of Erigeron canadensis L.;1%、5%、10% leaf extract of Erigeron canadensis L.;1%、5%、10%root extract of Euphorbia hyssopifolia Linn;1%、5%、10% stem extract of Euphorbia hyssopifolia Linn; 5%、10%leaf extract of Euphorbia hyssopifolia Linn; 1%、5%、10%root extract of Setaira viridis(L.)Beauv;1%、5%、10%root extract of Setaira viridis(L.)Beauv; And 5%、10% leaf extract of Setaira viridis(L.)Beauv has Inhibition of seed germination in varying degrees . With 10 %leaves extracts on seed germination inhibition of the most significant. seed germination to CK is 57.8%、7.8%、9.5%。5. Erigeron canadensisL., Euphorbia hyssopifolia’s extract of roots, stems and leaves, to the effect of inhibition of seed germination percentage order Allelopathic effect to Flaveria index is leaves > stems >roots, Setaira viridis(L.)Beauv. Extract of roots, stems and leaves, to the effect of inhibition of seed germination percentage order allelopathic effect to Flaveria allelopathic index is roots > stems >leaves, the roots Allelopathic effect to Flaveria of Setaira viridis(L.). Is greater than Erigeroncanadensis L. and Euphorbia hyssopifolia’s.6. Erigeron canadensis L., Euphorbia hyssopifolia Linn. And Setaira viridis(L.)Beauv. extract of roots, stems and leaves, to the effect of germination rate of Flaveria indicate that different concentrations of the water extract of seed germination peak in the 2-4 days, then tend smooth, Germination trend has no obvious difference to CK, Germination rate form high concentrations of extract the germination rate is below its low concentration.