Effect of maleic hydrazide on peroxidase isoenzymes in relation to rooting hypocotyl cuttings ofPhaseolus mungo

A time course study of changes in the pattern of peroxidase isoenzymes shows that two new isoenzymesa andb appeared in hypocotyl cuttings cultured either in indolyl-3 acetic acid (IAA) + sucrose or in water but not in maleic hydrazide (MH). Roots were also initiated in the former two cases but not in the last case. That these isoenzymes may be associated with root initiation is also evident from the fact that these appeared when hypocotyl cuttings were transferred from MH to IAA + sucrose. The time of appearance of these isoenzymes in different cultures also synchronized with the time of microscopic root initiation. While the isoenzymea disappeared,b persisted in cuttings transferred from IAA + sucrose to MH. The number of roots produced on cuttings transferred to MH was very low, though their development was normal. It is suggested that isoenzymesa andb may be associated with root initiation andc andd with root development.