Interaction between vivipary, abscissic acid (ABA) and Calcium in maize

174. INTERACTION BETWEEN VIVIPARY, ABSCISSIC ACID (AB A) AND CALCIUM IN MAIZE BENATIM., NEGRINI N ., RIVETIA A., COCUCCI M., GAVAZZI G. Dipartimento di Fisiologia delle Piante Coltivate e Chimica Agraria, Facolta di Agraria. Universita degli Studi di Milano, Via Celoria 2, 20133 Milano, ItalyDlFCA@ imiucca.csi.unimi.it vivipary. AEA. calcium Viviparous mutants are recognized by precocious embryo germination due to lack of dormancy. We have collected viviparous mutants in maize that can be divided into two classes: 1. those blocked in carotenogenesis, recognizable on segregating ears as white seeds yielding albino seedlings in contrast to wild type sibs, with yellow seeds and green seedlings. These mutants have reduced levels of endogenous AEA and are inhibited in their germination by exogenous AEA and are referred to as ABA biosynthesis mutants 2. the second class includes mutants unaffected in their carotenogenesis with normal levels of endogenous AEA but insensitive to the germination suppressive effect of exogenous ABA and referred to as ABA response mutants. Homozygous vp mutants can be recognized on immature ears on the basis of lack of carotenoids (class 1) or presence of red pigmentation of embryonic axis (some mutants of class 2). We exploited these diagnostic phenotype for an early identification of the mutants and their transfer to appropriate media before vivipary inception. The data we will present deal with the possible involvement of ABA and calcium on embryo dormancy.