ROOTING IN CUTTINGS OF MANGIFERA INDICA L.

Hard wood cuttings from mature mango trees generally fail to root under outdoor conditions. Under intermittent mist, however, hard wood cuttings from ringed shoots of mature trees have been found to root successfully (1, 4) giving up to 80% rooting with ringing plus IBA treatment.

Ringing of shoot has been found to promote rooting of cuttings but the girdling effect is a highly complex one and is associated with many changes in tissues which are more or less interrelated (2, 3). The present studies elucidate further the effect of ringing with particular emphasis on the question of endogenous rooting factors and incorporation of amino acids into protein, during rooting, as protein metabolism constitutes a fundamental aspect of regeneration.

The beneficial effect of ringing of shoot on rooting, studied by estimating the nutritional and hormonal rooting factors in ringed and non-ringed shoots of mature plants and juvenile seedlings revealed significant accumulation of carbohydrates in the region above the girdle. An increased synthesis of proteins in ringed shoot cuttings was associated with an increase in synthesis of the nucleic acids, DNA and RNA. Relatively greater incorporation of arginine and histidine, leucine, lysine, phenyl alamine and a few other amino acids into the newly formed proteins was related to the beneficial effect of ringing (table 1). Incorporation of large quantities of basic amino acids also took place when non-ringed cuttings were treated with IBA and prevention of incorporation of such amino acids into proteins, caused by a protein synthesis inhibitor like chloramphenical adversely affected root formation of cuttings. No significant difference in rooting factors as assayed by mung bean test was noted in tissues of ringed and non-ringed shoots.