Water content, lipid deposition, and (+)-abscisic acid content in developing white spruce seeds

Abstract

with inhibition of precocious germination, promotion of storage protein synthesis, acquisition of desiccation tolerWhole seeds, and isolated megagametophytes, seed ance, suppression of reserve mobilization, and induction coats and embryos from white spruce [Picea glauca of dormancy (Bewley and Black, 1994). (+)-ABA has (Moench) Voss ] were used to monitor water distribu- been quantified at diVerent stages in seed development tion by magnetic resonance microimaging, lipid com- of, among others, pine ( Kapik et al., 1995) and peach position by gas chromatography, and (+)-abscisic acid (Piaggesi et al., 1991). content ((+)-ABA) by enzyme-linked immunosorbent In developing seeds, water distribution is a factor in assay, during seed development. The highest (+)-ABA the inhibition of premature germinative events; presumcontent was detected in the female gametophytic ably it impacts on the transition of cellular activities from tissue, this at 11 d after pollination (DAP). Reserve an exclusively developmental programme to an exclusdeposition was evident up to 59 DAP in the female ively germinative/growth programme ( Kermode, 1995). gametophyte and in the developing embryo. The Changes in the water distribution of developing seeds can maturation drying period occurred between 59 DAP be assessed either by invasive or by non-invasive techand 93 DAP. At 59 DAP, the seed contained 24% niques. The bulk water transport in conifers was examined