Cobalt has essential physiological action on both animals and plants. For the latter it can raise plant’s nitrogen- fixing ability and saccharine content. Spray of cobalt mixed with other nutritive elements can improve the germinatity of seeds and the yield of fruit. For specifying the nutritive function of cobalt upon watermelon

isotope 60Co was mixed into a complex leaf nutritive aquor and the regularity of transferring and absorbing cobalt in the watermelon’s body was investigated.