OBJECTIVETo study the variations of flavonoids contents in vine tips of sweetpotato (Ipomoea batatas) among different varieties, parts and the time of topping.

METHODThe flavonoid contents in leaf, petiole and stem of vine tips at 6 different topping time of 3 varieties for vegetable-use Pushu 53, Guangcaishu No. 2 and Fushu 7-6, which were collected from Chongqing were determined by UV spectrophotometry with rutin as a standard substance.

RESULTThe results showed that the flavonoid content of Guangcaishu No. 2 was higher than that of Pusu 53, so was that of Pusu 53 than that of Fushu 7-6. The average flavonoid contents in leaf of 3 varieties were between 3.66 mg x L(-1) and 11.09 mg x L(-1) during 6 topping time, and those in petiole, stem were between 2.20-5.26 mg x L(-1) and 4.03-7.79 mg x L(-1), respectively. The rations of average flavonoid contents in leaf, petiole and stem to the total contents of vine tips among 3 varieties during their whole topping periods were 46.71%, 20.65% and 32.63%, respectively. The contents during earlier topping time were higher than those of later periods. The variance analysis of flavonoid contents revealed that there was significant difference between different varieties, parts and time of topping and significant interactions among varieties, parts and time of topping.

CONCLUSIONThe results of the study indicate that the contents of flavonoid should be considered for the breeding, cultivation and industrialization of sweetpotato for vegetable-use.