Cytokinin and abscisic acid in xylem sap of mango cv. Alphonso grafted on rootstocks of contrasting vigour

摘要

A great deal of emphasis is being laid on enhancing the orchard efficiency and productivity of fruit crops through high-density plantation. Out of various methods suggested, use of size controlling dwarfing rootstocks (Turkey, 12) and application of growth retardants (Davics and Curry, 3) have been relatively more successful. Though the induction of dwarfing through the use of size controlling rootstocks has been promising in apple, progress in this direction has been little in mango. This is because of lack of information on physiological basis of dwarfing effect of rootstocks. Investigations made earlier have revealed delayed compatibility, nutrient supply, endogenous growth substances, alteration in conducting tissues, phenolic content etc., as some of the possible factors for dwarfing effect of rootstocks on scion (Lockard and Schneider, 10). There is a limited evidence that rootstock-scion relationships are mediated by root derived plant growth regulators. Attempts have thus been made to study the contents of growth substances, cytokinins-zeatin riboside (t-ZR) and dihydrozeatin riboside (DHZR) and abscisic acid (ABA) in xylem sap of cv. Alphonso raised on 2 rootstocks of contrasting vigour and elucidating their possible role in the regulation of scion vigour.