BIOSYNTHESIS AND PARTITIONING OF INDIVIDUAL GLUCOSINOLATES BETWEEN POD WALLS AND SEEDS AND EVIDENCE FOR THE OCCURRENCE OF PAPS-DESULFOGLUCOSINOLATE SULFOTRANSFERASE IN SEEDS OF OILSEED RAPE (BRASSICA-NAPUS L)

(SO42-)-S-35 and S-35-labelled glucosinolate precursors were administe red to intact whole-pods and seeds to investigate the capacity of oils eed rape (Brassica napus L.) pod tissues to carry out reactions of the glucosinolate biosynthetic pathway, S-35-desulphobut-3-enyl and S-35- desulphoindol-3-ylmethyl glucosinolates were-converted to their sulpho nated intact-glucosinolate' homologues by isolated immature seeds. A n eutral sulphur-containing fraction was isolated from pod walls and sho wn to be associated with glucosinolate biosynthesis, Further purificat ion of this fraction showed the presence of desulphoglucosinolates, th e penultimate intermediates in the glucosinolate biosynthetic pathway. Chemical characterization and quantification of these intermediates s howed that their types and levels corresponded to the glucosinolate bi osynthetic activity of pod-wall tissues.'Partition quotients' (Pq) wer e calculated for individual glucosinolates from S-35-labelling data an d used to describe the apportionment of newly synthesized glucosinolat es between pod walls and seeds, Results from continuous feeding studie s with pods and (SO42-)-S-35 indicated that individual rapeseed glucos inolates have characteristic Pq values.