Madhuri Sharon, Cirumalla Rajaram G and Manisha Sharan
Purpose of the present work was to study whether the effect of g - radiation doses given to dry an soaked (where germination initiation has begun) seeds of Punica granatum, are carried to the explants also that are used for in vitro culture or is it limited to the seedling growth only. To investigate the effect of g - radiation on endogenous level and radiolysis of IAA; soaked and dry seeds were irradiated with 1, 5, 10 and 15 kR of g - radiation and germinated in vitro. Callus was regenerated from various explants of these seedlings. Endogenous level of IAA in root, stem and callus and radiolysis of IAA in different media viz. aqueous or cell extract was recorded. All doses, except 1 kR, inhibited the seedling growth. Callus initiation and growth was delayed by 10 and 15 kR, whereas 1 and 5 kR stimulated the callus growth. Endogenous level of IAA in root, stem and callus was suppressed by all the doses of g - radiation, except 1 kR; where it was more. Radiolysis of IAA in aqueous and cell extract was less than radiolysis of IAA crystasl. Higher doses of g inhibited growth of seedlings, callus derived from them and endogenous level of IAA. As compared to pure IAA, IAA present in aqueous solution or in cell extract had less radiolysis.
