Fig. 3. Isopentenyl adenine and discadenine production in wild-type and
iptA-null strains. Isopentenyl adenine (squares) and discadenine
(circles) recovered from wild-type cells (filled symbols) and mutant cells
(open symbols) at the indicated times of development. The horizontal line
indicates the approximate level of cytokinin required to induce spore
formation fully.