Plasmodesmata in Growth and Development

Abstract

The evidence of a role for plasmodesmata in differentiation and development is as yet purely circumstantial. However, the amount and quality of the evidence, supported by the recent, although equally circumstantial, evidence from equivalent animal systems, is now becoming difficult to explain away. I shall begin by stating three hypotheses, fundamental to this Chapter, and to deal with certain assumptions. The first hypothesis was stated by Strasburger (1901) and repeated by Lundegårdh (1922) and by Münch (1930): it is that the plasmodesmata are constructed and function not only so as to facilitate transport of solutes between cells but also to guard the genetic individuality of those cells. Similar ideas were expressed by Bennett (1973a,b) concerning the construction and functioning of junctions between embryonic animal cells. The second hypothesis is also an old one, and can be traced back at least as far as Goebel (1897). It states that cells isolated from neighbouring cells will be free to undergo some form of special development. In lower plants they may even regenerate whole new individuals. The converse is not true. Cells in communication with other cells remain free to develop or differentiate in special ways.