Biological Characteristics And Control Method With Flower Bud Inhibitors Of Invasive Plant Flaveria Bidents(L.) Kuntze

Flaveria bidentis(L.)Kuntze is first-grade malignant invasive plant that has seriously threatened China's ecological environment in recent years.The plant has a tendency to gradually spread to other suitable area.A comprehensive understanding of its distribution,botanical characteristics and seed propagation,identifying F.bidentis rapidly and developing technology of flower bud inhibitor to control plants provides support for effective prevention and control of F.bidentis(L.)Kuntze.Our research proceed by following two aspects:1.Investigation of field occurrence,biological character observation,rapid identification and seed dispersal characteristics of F.bidents(L.)Kuntze.Firstly,a comprehensive investigation was carried out on the field of F.bidentis(L.)Kuntze.,and the botanical characteristics such as vegetative organs and reproductive organ were studied.The samples of F.bidentis(L.)Kuntze(3 samples),three invasive species of Compositae and one homologous species(14 samples)in China and 111 ITS molecular sequences published on NCBI were downloaded for cluster analysis.The biological characteristcs and seed dispersal by wind and water of F.bidentis(L.)Kuntzeseeds in China were studied.The results show that F.bidentis is mainly distributed in Hebei,Henan,Tianjin and Shandong provinces of North China.F.bidentis(L.)Kuntzehave high rate of seed setting(average 6698 mature seeds per plant)and high germination rate(98.6%).There was a significant positive correlation between plant height and mature seeds.ITS molecular sequences(111 copies)of 20 species from Flaveria genus and 14 species from relative genus were downloaded,which have been conducted systematic cluster analysis,shows that F.bidentisin China has shortest genetic distance with F.bidentis(L.)Kuntzeof North American model specimen.Achenes can float on water surface for more than 2 days,but travel by slight breeze is only within 1 meter due to lacking of pappus.2.Study on prevention and control technology of flower bud inhibitors of F.bidentis(L.)Kuntze.Accounting to the biological characteristics of F.bidentis(L.)Kuntzewith large seed setting and highly survival,we sprayed flower bud inhibitors at five key reproductive stages(final vegetative,the initial of flower bud differentiation,the initial of microspore and megaspore development,the initial of pollen grain development and florescence);Spraying 0.06%flower bud inhibitor at the initial of microspore and megaspore development,using paraffin section to observe the pharmacodynamics of 0,5,10,15 days;extensive prevention and control of field in Tianjin and flight prevention experiment of UAV in Hebei Province.The results showed that sprayed different concentration flower bud inhibitors(0.03%,0.06%,0.12%and 0.18%)at five key reproductive stages were screened in Nanjing greenhouse at 2017.Among them,spraying 0.06%flower bud inhibitor,which seed germinability rate compared with the control have decreased to 4.89%;Sprayed six concentrations flower bud inhibitors(0,0.02%,0.04%,0.06%,0.08%,0.10%)at five key reproductive stages were screened in Nanjing greenhouse at 2018.We found that 0.06%concentration of flower bud inhibitor had the best inhibition effect,the seed germination rate compared with the control have decreased to 6.20%.we found flower bud inhibitors(NJW001)affected anther caused tapetum disintegrates ahead of time,pollen grains are abnormal,and in pistils embryo sac structure is destroyed,which resulting in seed abortion.Finally,we spraying NJW001 to control it,when Flaveria bidents in the initial of microspore and megaspore development.We spraying 0.06%flower bud inhibitor in order to control of large area pharmacy in Tianjin,which seed germinability rate compared with the control have decreased to 6.35%,and flower bud inhibitor treatment on Flaveria bidents by urunanned aerial vehicle in Hebei,which results showed that 0.06%concentration of flower bud inhibitor have decreased 78.97%,it had the best effect.Therefore,considering the cost and control effect,it is best to spraying 0.06%flower bud inhibitors in the initial of microspore and megaspore development.