Concerning the Sinuous Shape of Leaf Epidermal Cells

Abstract

SUMMARY The geometric features of the sinuous shape of intercostal epidermal cells of the upper epidermis of the leaf of the fern Dryopteris thelypteris (L.) were studied. These cells have an average and probability distribution for the number of anticlinal walls similar to those in tissues expanding in two dimensions as reported earlier. No angles between anticlinal walls were <90° or >180° thereby indicating that growth stresses do not alter the shape of cells during the final expansion stage of development. Both the number of convex and concave lobes per cell approaches the binomial expansion of a2(p(a)+q(b))4 while the formula a4(p(a)+q(b))8 describes the distribution for all lobes. Rare gametophtyes were found in which the cells were transformed into sporophytic, leafy types including xylem, spines and sinuous epidermal cells. The occurrence of this last feature indicates that the wavyness of epidermal cells can be achieved in an isolated layer of cells. The data best fit the hypothesis that each cell regardless of size and shape produces four growth centres, each of which arrives at a cell wall site by chance movements and forms either a concave or convex lobe.

Of puzzles and pavements: a quantitative exploration of leaf epidermal cell shape

“…a). Monocot and gymnosperm pavement cells tended to exhibit higher solidity values (less undulating margins) consistent with the qualitative literature for monocots (Linsbauer, ; Watson, ; Greguss, ; Stoddard, ; Ellis, ; Korn, ; Fig. a).…”

“…a). Fern pavement cell margins have been described as more undulating than in the eudicots (Korn, ), an observation that held generally true in our data set. However, ferns exhibited the widest range of solidity values (0.38–0.98; Fig.…”

Mechanical stress initiates and sustains the morphogenesis of wavy leaf epidermal cells

“…The complex growth pattern of leaf pavement cells makes them an ideal model to study mechanisms underlying the formation of complex shapes in plant cells (Bidhendi and Geitmann, 2018;Jacques et al, 2014;Majda et al, 2017;Mathur, 2004;Sapala et al, 2018;Szymanski, 2014). Various biomechanical concepts have been proposed to explain the formation of lobes in pavement cells (Jacques et al, 2014;Korn, 1976;Korn and Spalding, 1973;Majda et al, 2017;Sapala et al, 2018;Watson, 1942). Hypotheses range from bending of the cell walls resulting from the growth of cells in a confined space, inhibition of pavement cell expansion due to forces from cuticle or inner mesophyll layers to localized outgrowth of the anticlinal cell walls (Korn, 1976).…”

Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells

“…The epidermal pavement cells of Arabidopsis thaliana leaves and cotyledons are a good model system for understanding how plant cells form complex shapes because their walls develop from simple arcs to contain multiple undulations of varying sizes (Mathur, 2004(Mathur, , 2006Fu et al, 2005). In a single cell, these undulations, hereafter referred to as lobes, either extend out of the cell (concave lobe) or into it (convex lobe) (Korn, 1976). As lobes are shared between neighboring cells, each lobe has both a concave side and a convex side.…”