Effects of Spraying Cytokinin on Abscission Rate and Enzymic Activity of Flowers and Pods of Cowpea

Four cowpea varieties, ‘E Jiangdou 2’, ‘E Jiangdou 6’, ‘E Jiangdou 7’, and ‘Meiguo Didou’, provided by the Hubei Province Engineering Research Center were selected as research materials. We sprayed cytokinin on leaves in budding stage to study its effects on the abscission of flowers and pods in the field. At 7, 14, 28 and 42 d after spraying, we analyzed the yields and abscission rates of flowers and pods, and detected the enzyme activities of polygalacturonase and cellulase in premature shedding of flowers and pods.Results showed that after spraying cytokinin, the abscission rates of flowers and pods in different cultivars were lower than those in the control, but yields in different cultivars were higher, with the differences being highly significant (P < 0.01). Furthermore, the polyga-lacturonase activities of cowpea were significantly lower than those of the control at 14 d, 28 d and 42 d after spraying (P < 0.05), and significantly lower at 7 d after spraying (P < 0.01). The cellulase activities of fallen flowers and pods were significantly (P < 0.05) lower than those of the control at 7 d and 42 d after spraying, and significantly (P < 0.01) lower at 14 d and 28 d after spraying. The above results indicated that the activities of polygalacturonase and cellulase were regulated by spraying cytokinin, which resulted in reducing the abscission rate of flowers and pods and regulating yield in cowpea.