Sulfur requirements of rape seedlings with various backgrounds of seed glucosinolate contents

The relationships of sulfur requirments，glucosinolate and sulfur contents in plant tissue and roots of rape seedlings with different glucosinolate contents in seeds and S supply were studied by sand culture in greenhouse．The results show that to obtain highest yield (biomass),more S was required by rape seedlings with lower glucosinolate contents in seeds than those with higher glucosinolate contents in seeds．S contents in plant tissue for three varieties were significantly exponentially correlated with S supply，and no difference existed among the varieties．However，S contents in root were highly correlated with S supply in quadratic curve，and there were differences among varieties with different glucosinolate backgrounds．Quadratic regressional relation was found between glucosinolate contents in plant tissue and S supply.Tissue glucosinolate contents were higher in varieties with higher background glucosinolate，and they aiso synthesized and accumulated more glucosinolate in plant tissue than those with the lower background glucosinolate，showing some resistance to tissue glucosinolate aecumulation．Then it is important to apply more S fertilizer to double lower rape varieties．