5. Conclusion
From the present study, it is indicative that ABA is one of the key determinants that decide the mode of in vitro
differentiation of cotyledonary explant types; and the direct shoot regeneration is delayed in Cot due to the
presence of higher amount of ABA in the active form. Presence of higher amount of ABA in Cot explants also
indicates less endogenous cytokinin responsive proteins, which have previously been demonstrated by us
through proteomic investigation [18]. On the other hand, up regulation of several cytokinin responsive proteins
in Cot E during induction of in vitro shoot differentiation in presence of exogenously applied cytokinin in nutrient
medium reduces the ABA activity maintaining cellular cytokinin homeostasis. Hence, this investigation
clearly demonstrates the role of ABA as determinants of shoot differentiation in Vigna radiata.
Acknowledgements
Authors are thankful to the Department of Science and Technology, Government of India (DST Sanction No.
SR/SO/PS-58/05) for financial support and to the Director, Bose Institute for providing all infrastructural facilities.