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CHANGES IN ACTIVITY AND ISOZYMES OF PEROXIDASE DURING IN VITRO DEDIFFERENTIATION AND CALLUS PROLIFERATION IN DIFFERENT EXPLANTS OFSOYBEAN

KUNWAR SHOAIB AND JAVED IQBAL*

Abstract: Total activity of peroxidase and its isozymic profiles in the explants of soybean during the process of dedifferentiation was investigated. The explants obtained from aseptically germinated seedling were transferred to callusing medium containing MS salts supplemented with 9.0 uM (2.0 mgl^-1) 2,4-D and 6.9 uM (1.5 mgl^-1) Kinetin. Total activity of peroxidase increased in hypocotyl (0.75 to 1.80), cotyledon (0.55 to 1.20) and internode (0.31 to 1.00) during dedifferentiation process with a peak of activity observed prior to callus initiation. In leaf however, there was a sharp decline in enzyme activity (1.42 to 0.30) after excission with a moderate increase (0.96) prior to callus initiation. Electrophoretic pattern of peroxidases were organ specific. The explant of hypocotyl internode and leaf had three band each but with different Rf values. The expant of cotyledon showed only one isozyme. In all the explants marked changes were associated with the process of dedifferentiation. Once the meristematic activity was triggered no further qualitative changes took place in the isozymes. Calluses of all the four explant had only two bands and these persisted during successive subcultures.

Department of Botany, Govt. F.C. College, Lahore, Pakistan.
Department of Botany, University of the Punjab, Quid-e-Azam Campus, Lahore-54590, Pakistan.