Rape (Brassica napus L.) is sensitive to boron deficiency and usually gets depressed in production when it becomes severe.Boron deficiency restrains reproductive growth more than vegetative growth of rape.Yellow-seeded rape (Brassica napus L.) is characterized by thinner seed coat and lower hullpercentage,which is correlated with higher oil,high prote in,and lower crude fiber contents as is compared with black seeded rape.Therefore,breeding of yellow seeded rape has become one of the main objectives in rapeseed production.To realize that target,it is important to explore physiological characteristics of yellow seeded rape in soils low in boron content at the flowering stage,and differences between yellow seeded and black seeded rapes.Two isogenic genotypes of rapes,yellow seeded and black seeded rapes (Brassica napus L.) were used in a field experiment for that purpose.Results show that in soils low in boron content,black seeded rape was more capable than yellow seeded rape of redistributing N,P and K in bottom leaves of the plants.Low soil boron content led to reduction of size and dry weight of floral organs,of either yellow seeded or b lack seeded rape,affected.the length s of p istil and stam en m ore of yellow seeded rape than of b lack seeded rape,and dulled the viability of pollens of both rape genotypes,but the effect was more obvious on yellow seeded rape than on black seeded rape.Besides,low soil boron content lowered the contents of soluble sugar,starch,free proline and soluble protein in the stamen and pistils of both rape genotypes,but the effect was more significant on yellow seeded rape than black seeded one.Compared to black seeded rape,yellow seeded rape was more sensitive to boron deficiency.