Differences were analysed among the CMS line L17A and its maintainer line L17B, the sterile plant L18A and the fertile plant
L18B of the GMS line L18AB and the genic sterile plant (GCDMS HA) and cytoplasmic sterile plant (GCDMS BA) of GCDA 1, a genic and cytoplasmic double MS (GCDMS) line in their
enzymatic activity and isoenzyme patterns. CAT activity decreased significantly with bud development in all the three types of male sterility, while POD activity remained little changed. POD activity in GCDMS HA was similar to that in L18A, being highly significantly stronger than that in L17A and L17B and significantly higher than that in GCDMS BA and L18B. CAT activity in L17A was same as that in GCDMS HA, being highly significantly stronger than that in L17B and L18A and significantly higher than that in of GCDMS BA and L18B. In the early period of bud development, no significant difference was observed between CMS and GCDMS in their isoenzyme patterns though POD activity appeared low in GCDMS HA and GCDMS BA as compared with that in CMS and GMS lines. In the late period of bud development, the isoenzyme patterns and activity of POD became quite similar in all genotypes. The isoenzyme patterns of EST of the CMS lines were markedly distinguishable from those of the GMS or GCDMS lines, the former having three slowly moving bands in the small buds while the latter having none. A band with medium moving speed was noticed in the EST enzyme pattern of GMS, which had a higher activity than that in CMS or GCDMS lines. However, more similarity appeared as the bud grew, and their differences were manifested only in migration rate. The expression of POD and EST enzymatic activity and isoenzyme patterns of CMS, GMS and GCDMS indicate that interactions exist between the GMS and CMS sterile gene systems.