Utilizes UDP-glucose as the sugar donor and catalyzes the formation of O-beta-D-glucosyl-cis-zeatin from cis-zeatin. May regulate active versus storage forms of cytokinins and could have an impact on seed growth. cis-zeatin + UDP-alpha-D-glucose = H(+) + O-beta-D-glucosyl-cis-zeatin + UDP Optimum pH is 7.5. Highly expressed in root. Expressed at lower level in kernel and cob. Weakly expressed in leaves. Weakly or not expressed in stems. Belongs to the UDP-glycosyltransferase family.