Seed Reproductive Characteristics And Herbicide Screening Of Field Bindweed (Convolvulus Arvensis Linn.) In Cotton Field Of Xinjiang

Field bindweed（Convolvulus arvensis Linn.）,a serious perennial weed of the Convolvulaceae family,is resistant to phlegm,drought and salt and alkali.It is very suitable for extreme arid climate,soil salinization and poor soil environment,and it has strong breeding and regeneration ability,so it has become one of the ten most noxious weeds in the world.Field bindweed is widely distributed in Xinjiang province of China and seriously endangers the cotton field and orchard ecosystem.It often forms a single dominant community,resulting in crop yield reduction and restricting the development of crop economy.In this study,1)laboratory experiments were conducted to examine the influence of environmental factors,including temperature,salinity-alkalinity,drought and pH,on germination of field bindweed seeds collected from Alaer and Xinhe.2)The dormancy and germination of field bindweed seeds were studied under natural and man-made conditions by setting different outdoor and indoor storage methods.3)The control effects of five herbicides,namely,fomesafen,glyphosate,glufosinate ammoniume,trifloxysulfuron sodium and flumioxazin,on field bindweed at different growth stages were studied by pot culture in greenhouse.The results are as follows:1 Effects of environmental factors on seed germination of field bindweedSeeds did germinate at 5℃and had a maximum germination at 30-40℃,which was followed by a decline in germination at 45 and 50℃.Seeds germinated at alternating temperature regimes from 15/5 to 45/35°C,with maximum germination at the alternating temperatures of 40/30°C.Germination was reduced by saline and alkaline stresses and no germination occurred at≥300mM NaCl or≥250mM NaHCO₃ concentrations.Moreover,germination decreased as water potential became more negative（-0.1 to-1.0MPa）.Seeds from Xinhe area could not germinate at-0.6MPa and only 2%germination was observed at-1.0MPa for seeds collected from Alaer.However,pH values from 5 to 10 had no significant effect on germination,and pH is not a main factor limiting the seed germination of field bindweed.2 Effects of storage methods on dormancy and germination of field bindweed seeds.Both outdoor burial and hanging methods could effectively relieve the dormancy of field bindweed seeds under natural conditions,and the burial depth affected the germination rate and dormancy relief rate of field bindweed seeds.Burying depth of3-10cm was conducive to the germination of field bindweed seeds under natural conditions.Dry storage at room temperature and dry-cold storage were more effective methods for the indoor preservation of field bindweed seeds.3 Control effects of five herbicides on field bindweed in cotton fields at different growth stages.The control effects of five herbicides,namely,fomesafen,glyphosate,glufosinate ammoniume,trifloxysulfuron sodium and flumioxazin,on field bindweed at different growth stages were studied by pot culture in greenhouse.The results showedthat:,Allfiveherbicides,glyphosate,glufosinateammoniume,trifloxysulfuron sodium and flumioxazin,could control field bindweed in cotyledon stage.With the increase of the growth period,the dosage of fomesafen,glyphosate,trifloxysulfuron sodium and flumioxazin used in the control of field bindweed increased.Therefore,glufosinate ammoniume is recommended tocontrol field bindweed after the 3-4 leaf stage.