| Résumé | Abscisic acid (ABA) plays important roles in many aspects of seed development, including accumulation of storage compounds, acquisition of desiccation tolerance, induction of seed dormancy, and suppression of precocious germination. Quantification of ABA in the F1 and F2 populations originated from crosses between wild type and an ABA-deficient mutant aba2-2 demonstrated that ABA was synthesized in both maternal and zygotic tissues during seed development. In the absence of zygotic ABA, ABA synthesized in maternal tissues was translocated into the embryos and partially induced seed dormancy. We also analyzed the levels of ABA metabolites, gibberellins, indole-3-acetic acid (IAA), cytokinins, jasmonates and salicylic acid (SA) in the developing seeds of wild type and aba2-2. ABA metabolites accumulated differentially in the silique and seed tissues during development. Endogenous levels of SA were elevated in aba2-2 in the later developmental stages, whereas that of IAA was reduced compared to wild type. These data suggest that ABA metabolism depends on developmental stages and tissues, and that ABA interacts with other hormones to regulate seed developmental processes. |
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