INVIVO ROLE OF INDOLE-3-ACETIC-ACID, GIBBERELLIC-ACID, ZEATIN, ABSCISIC-ACID AND ETHYLENE IN FLORAL MALFORMATION OF MANGIFERA-INDICA L

Abstract The endogenous levels of indole‐3‐acetic acid (IAA), gibberellic acid (GA3), zeatin, abscisic acid (ABA) and ethylene were studied in panicles/shoots of Dusheri mango at four stages viz., (I) fully swollen buds; (II) bud inception; (III) fully grown panicles prior to full bloom and (IV) fully grown panicles at full bloom, for three consecutive years. The malformed panicles and the shoots bearing malformed panicles (SBMP) possessed lower levels of IAA in relation to healthy panicles and shoots bearing healthy panicles (SBHP) at stage I, II, III and IV. The malformed panicles and SBMP maintained lower levels of GA3 than healthy panicles and SBHP at stage I. However, the converse was true for stages II, III and IV. The malformed panicles and SBMP exhibited higher levels of zeatin compared with their healthy counterparts at the four developmental stages. Likewise, the contents of ABA and ethylene were also higher in malformed panicles and SBMP than healthy panicles and SBHP at all the stages. It is concluded that floral malformation is associated with malformin stimulated ethylene production and higher levels of ABA, gibberellic acid, zeatin and lower levels of IAA. Copyright © 1990, Wiley Blackwell. All rights reserved