Lack of Influence of the Epidermis on Underlying Cell Development in Leaflets ofPisum sativumvar.argenteum(Fabaceae).

We explored whether epidermal pressure regulates cell and organ growth in leaflets ofPisum sativumvar.argenteum,a mutant cultivar of the garden pea characterized by reduced adhesion between the epidermis and subjacent mesophyll. Developing leaflets of leaves arising at three positions on the seedling axis were peeledin situand grown to maturity in humidity chambers. The mature anatomy and morphology could be accurately assessed because wound responses normally associated with peeling were prevented by theArgmutation that permitted peeling without damage to the mesophyll and by the humidity chambers that protected peeled areas from desiccation. The mesophyll cell size, state of differentiation, and layering pattern as well as the overall morphology of mature, peeled leaflets were indistinguishable from those of mature, intact leaflets grown under the same conditions. The epidermis exerted no detectable regulatory effect on the expansion of the leaflets as a whole or on the tissue layers and cells within the leaflets.Copyright 1999 Annals of Botany Company. [ABSTRACT FROM AUTHOR]