Biochemical mechanism of radiation-induced dormancy in potatoes

Abstract

The studies described here will show that after gamma irradiation the dormant bud tissue of potatoexhibits a transient metabolic activation. During this period of active metabolic state, the tissueis capable of synthesis of DNA, RNA and protein. Apart from this there is increased utilization ofcarbohydrate for the production of the energy source ATP, to meet the demand for these processes.The site of active protein synthesis during this transient phase of activation has been recognised asnode' of the bud tissue and the synthesis of new proteins of the nuclei takes place within one toTWO hours after irradiation. The synthesis of nuclear acidic proteins was increased to about 3 to5 fold during the activation period compared to unirradiated bud tissue. The increase in acidic proteinsrithesis lasted for 41 hr. During the time there was no synthesis of histones. The synthesis ofhistoats started only 7 hr after irradiation showing about 10 fold increase over the control bud tissue.The increase in the concentration of non-histone protein prior to active RNA synthetic phase (2 hr)SliggeStiVe of their involvement in the metabolic activation ensured after gamma irradiation.Treatment gamma irradiation adversely affected the IAA synthesising system and the production of IAA treatment with low concentrations of IAA within 6 hr after irradiation could restore the IAA illnitsising capacity as well as reversal of sprout inhibition.