Study On Isolated Microspore Culture And Embryogenesis In Brassica Rapa L.

Brassica rapa L.(turnip) belongs to Cruciferae Brassica subspecies,is a biennial herbaceousplants.Turnips isolated microspore culture is difficult.This study chose four genotypes of turnips as testmaterials,using NLN-13liquid medium to culture,to find out that the effects of bud length,developmentstage,genes,heat shock condition and medium additive on isolated microspore culture of turnips.The resultsare as follows:(1) There is a corresponding relationship between buds size and pollen development stage.When budlength during2.0-2.49mm,the ratio of late period mononuclear microspores is more than the others,thehighest is62.4%,which is suitable for induction training.(2) The pollen microspores development are not synchronous,there are coexistence phenomenon ofcells.(3)The genotype is the key to the embryogenesis.In this test only Kashgar turnips had embryoids,butthe number of the embryoids is scanty.The other three turnip varieties had no embryos.(4)The temperature and interval of treatment are essential to the embryogenesis.While33℃pretreatment2d,turn out the optimal treatment for producing embryos.(5)Hormone variety and concentration affect the induction effects.To this experiment,the optimalconcentration combination is0.05mg/L6-BA+0.1mg/L NAA.(6)The results show that activated carbon is invalid to increase the rate of microsporeembryogenesis.On the contrary,with the increase of the concentration will inhibit embryo productionvolume,even no embryo arise.(7)The external morphology and the way of cell division are different under two differentdevelopment.Thus can preliminary presume that heat shock start microspore sporophytedevelopment,mononuclear microspore into a diploid cell.