Essentials of Plant Development

Abstract

In this appendix, features of plant development are reviewed that are important to various epigenetic phenomena. The flowering plants described in this book fall into two major classes, namely monocotyledonous and dicotyledonous, which diverged at least 100 MYA. Petunia, tobacco, and Arabidopsis are dicots, whereas maize is a monocot and belongs to the grass family. In the following summary, maize and Arabidopsis are used as examples of each class. An excellent review of the principles of plant development can be found in Patterns in Plant Development (Steeves and Sussex 1989), and detailed descriptions of maize and Arabidopsis development can be found in Arabidopsis (Meyerowitz and Somerville 1994) and The Mutants of Maize (Neuffer et al. 1996).

There are a number of features of plant development that make plants uniquely suited to epigenetics research. First, because of their indeterminate growth habit, epigenetic patterns of gene regulation in plants can be established throughout the life cycle. Once established, these patterns can be inherited by somatic cell lineages in much the same way as in other organisms.

Second, unlike many animal cells, plant cells undergo little migration relative to one another so that clonal lineages can be conveniently mapped during somatic development. Because of these well-characterized lineages, it is possible to discern non-clonal as well as clonal epigenetic patterns in plants, and examples of each are described in several chapters in this book. Third, the germ line in plants differentiates so late in plant development that many somatic lineages give rise to gametes.