EFFECT OF CHLORSULFURON ON MORPHOGENETIC AND DISORDERED CELL-DIVISIONIN CULTURES OF PASSIFLORA-EDULIS

We examined the effects of a sulfonylurea herbicide, chlorsulfuron, wh ich is known as a potent inhibitor of plant cell division, on morphoge netic cell division and disorganized cell division using the culture s ystem of multiple shoot primordia and callus of Passiflora edulis. The multiple shoot primordia tissue treated with chlorsulfuron failed to achieve shoot morphogenesis, and a large part of the tissue was necrot ized during the posttreatment culture, even when it was washed and tra nsferred to chlorsulfuron-free medium. The inhibition of Passiflora sh oot morphogenesis by chlorsulfuron was not reversed by the simultaneou s addition of branched amino acids, which are known to reverse the inh ibitory effect of chlorsulfuron. In contrast, the same treatment of ch lorsulfuron on the callus did not kill the cells, although the growth resumption was retarded by a prolonged lag period. The addition of bra nched amino acids enhanced the recovery growth of the chlorsulfuron-tr eated callus. These results suggest that the inhibition of disorganize d cell division (callus growth) by chlorsulfuron is reversible, wherea s morphogenetic cell division (shoot morphogenesis), which is under co mplex regulation, is inhibited irreversibly by chlorsulfuron. Qualitat ive differences between morphogenetic cell division and disordered sim ple proliferative cell division are discussed.