Plant Embryogenesis: Zygote to Seed

Abstract

Most differentiation events in higher plants occur continuously in the postembryonic adult phase of the life cycle. Embryogenesis in plants, therefore, is concerned primarily with establishing the basic shoot-root body pattern of the plant and accumulating food reserves that will be used by the germinating seedling after a period of embryonic dormancy within the seed. Recent genetics studies in Arabidopsis have identified genes that provide new insight into how embryos form during plant development. These studies, and others using molecular approaches, are beginning to reveal the underlying processes that control plant embryogenesis.

Evaluation of control transcripts in real-time RT-PCR expression analysis during maritime pine embryogenesis

“…The tissue used may be for itself a reason of this variation in the levels of expression of the housekeeping genes. Embryogenesis of higher plants is divided conceptually into two distinct phases: early morphogenetic processes that give rise to embryonic cell types, tissues, and organs and late maturation events that allow the fully developed embryo to enter a desiccated and quiescent state (West and Harada 1993;Goldberg et al 1994). It is therefore reasonable to assume that the level of expression of the genes tested has such a high variability due to these major developmental changes during embryo development.…”

Seed dormancy and germination

“…Embryogenesis, which is a morphogenesis phase, starts with the formation of a single-cell zygote and ends in the heart stage when all embryo structures have been formed (Mayer et al, 1991). It is followed by a growth phase during which the embryo fills the seed sac (Goldberg et al, 1994). At the end of the embryo growth phase, cell division in the embryo arrests (Raz et al, 2001).…”

Uncoupling histogenesis from morphogenesis in the vertebrate embryo by collapse of the transneural tube potential

“…We know of three other instances where the global control of pattern formation can be uncoupled from local controls of form or histological differentiation. This can occur during the formation of experimentally produced doublet cells in ciliated protozoans (Frankel, 19841, in the electrically induced regeneration of "pseudolimbs" in adult Xenopus (Borgens et al, 1979) and in the embryos of higher plants (Goldberg et al, 1994). There is no trivial explanation for the genesis of "embryos" whose external form continued to develop following collapse of the TNTP while dissolution of internal structures occurred simultaneously with a failure of organogenesis.…”