ZYGOTIC EMBRYOGENESIS IN ANTHURIUM (ARACEAE)

Morphological, anatomical, and histochemical aspects of zygotic embryo genesis by Anthurium andraeanum Lind. were investigated from 4 to 24 w k postpollination. Anatomical features were correlated with morphology of the spadix and capacity of embryos to germinate in vitro. Developm ent from a single-cell zygote to fully mature seed takes 24 wk. The su spensor was two ranked and obvious during the early stages of embryoge ny. It was apparent by week 8, substantial until week 14, and diminish ed rapidly until its absence by week 22. Differentiation of the shoot apex, cotyledon, and protoderm occurs at 14 wk. The embryo starts to d erive nutrition from the endosperm at this time, and germination of cu ltured ovules reached 56%. By 20 wk the shoot apex had visible leaf pr imordia and the root apex was clearly defined. The cotyledon was well developed and surrounded the shoot tip. The storage of protein and sta rch was at its greatest in the endosperm and embryo. Furthermore, 100% germination of cultured ovules and embryos occurred at 20 wk and ther eafter. Fully mature embryos at 24 wk are green and contain protoxylem elements.