Light and fluorescence microscopy studies indicated that chlorophyll was absent from the guard cells of the lady slipper orchids, Paphiopedilum insigne (Wall.) Pfitz, P. insigne(hybrid), P. venustum (Wall.) Pfitz and P. harrisseanum Hort. In the guard cells of P. aureum hyeanum Hort., however, very slight red fluorescence suggested that chlorophyll and hence chloroplasts were present.
Ultrastructural studies of the lower epidermis of P. insigne (hybrid) confirmed the absence of chloroplasts in guard and epidermal cells although plastids of an unusual structure were found in these cells. In fully developed epidermal cells the plastids contained large amounts of a fibrous, possibly proteinaceous substance, spherical, lightly staining vesicles and an electron‐dense material located in reticulate and non‐reticulate regions. Additionally, latticed crystalline inclusions and plasto‐globuli were occasionally observed in the epidermal cell plastids. In plastids of fully developed guard cells the fibrous material, starch and plastoglobuli were present.
From the earliest stages of development of the epidermal tissue starch was present in both epidermal cell and guard cell plastids. At maturity, however, starch had accumulated to greater levels in the guard cell plastids and had entirely disappeared in the epidermal cell plastids. In differentiating epidermal tissue, plasmodesmata were found between neighbouring epidermal cells and between guard and epidermal cells. At maturity, plasmodesmata between guard and epidermal cells were not observed. Mitochondria were particularly abundant in guard cells. Large oil drops developed in guard and epidermal cells, being especially abundant in the former at maturity.
Our results confirm the observations of Nelson & Mayo (1975) that certain lady slipper orchids possess functional stomata the guard cells of which do not contain chloroplasts.
In the leaf epidermis of the monocotyledon Anemarrhena asphodeloides Bunge a characteristic pattern of stomata and papilla cells is developed.
The ontogeny of both kinds of specialized cells is initiated by a formative mitosis yielding one daughter cell with aberrant structure and competence.
It is shown that these distinctive cell types affect the fate of neighbouring epidermal cells. The final epidermal pattern is due to random initial events, as well as cell lineage, and cell‐to‐cell interactions during development.
The epidermis of Anemarrhena asphodeloides is composed of three distinct cell types: guard cells of the stomata, ordinary epidermal cells, and papilla cells occurring in files wedged between files of ordinary epidermal cells.
Both stomata and papilla cells have their origin from formative mitoses in the young protoderm. Their differentiation described on the basis of light and polarization microscopy involves a decrease in cell contacts and changing orientation of cellulose microfibrils of the cell wall.
These changes are discussed in relation to the pattern of cell divisions and to the modification of cell shape during epidermal development.
23 herbaceous taxa distributed in 9 orders and 10 monocotyledonous families were documented on nature of stomata.
Only arched epidermal cells were observed. Anomocytic, paracytic, tetracytic and hexacytic and mixed stomata were recorded.
Stomata size ranged from 17.47µm ± 0.23 x 16.13µm ± 0.29 in Smilax kraussiana to 58.80µm ± 0.33 x 50.40µm ± 0.39 in Commelina benghalensis and stomata index values varying from 0.57% in Aframomum sceptrum to 14.40% in Rhaphidophora africana were documented in this study.
Epidermal characters of 15 Allium species autochthonous in Czechoslovakia were studied. Particular species have amphistomatous or hypostomatous leaves and vary greatly in the shape of epidermal cells, in sinking of stomata and in cuticular sculpture (presence or absence of ridges around the entrance of stomataI tip and presence of micropapillae or ridges on the cell surface).
Variation in particular species is small but is considerable between them. Closely related species have the same type of epidermis, but sections and subgenera. do not differ from each other.
A great deal of variation appears to be correlated to water stress of the biotopes of particular species. Convergency of characters is seen in different infrageneric taxa. Epidermal characters are very useful in identifying sterile plants.
The stomatal apparatus of Orontium aquaticum is confined to the upper epidermis of the leaf and consists solely of two guard cells, with no accompanying subsidiaries.
The guard cells, which possess flangelike thickenings of the wall flanking the stomatal pore, are sunken and largely obscured by the overlapping ordinary epidermal cells. Lysichitum and Symplocarpus, genera closely related to Orontium, also lack subsidiaries.
This indicates that the stomatal complex within the Araceae is probably more diverse than was previously thought.