Linear Aggregations of Stomata and Epidermal Cells in Tradescantia Leaves: Evidence for Their Group Patterning as a Function of the Cell Cycle

Abstract

We tested Charlton's hypothesis (1990) that stomata are present and patterned in linear cell aggregations using the monocot Tradescantia. We examined the following features of the leaf epidermis in support of this theory: linear groups (strings) of stomatal complexes and of epidermal cells were sought in immature and mature regions of entire leaves; the lengths (in cell number) and incidences (numerical occurrence) of both string types were determined; the uniformity and progression of stomatal differentiation within strings were studied; physical characteristics of differentiating strings within cell files were measured. Undifferentiated epidermal cells from the leaf base were stained with DAPI to reveal precursors of stomatal strings immediately proximal to the stomatal initial region. The results indicated that the Tradescantia epidermis in the leaf blade consists of linear groups of stomata and epidermal cells, which did not change in cell number nor incidence during development. The incidence of stomata by length was nonrandom. Although incidence decreased with string length, the decline was not linear nor exponential. Stomatal strings show cell cycle synchrony in DAPI staining of stomatal precursors and synchrony of stomatal differentiation within a string. The irregularity in the length of the stomatal development region, and each differentiation stage in it, by cell file was consistent with the variation in string length and unity in string development. The evidence supports Charlton's hypothesis that cells are patterned based on their position in the cell cycle and that linear groups of stomata reflect cell lineages, which maintain a degree of cell cycle synchrony.

The Subtilisin-Like Serine Protease SDD1 Mediates Cell-to-Cell Signaling during Arabidopsis Stomatal Development

“…The observed arrest of stomatal precursors halted at the M/GMC stage is similar to the formation of arrested stomata in the monocots Tradescantia, Ruscus, and Aeonium and the dicots Anagallis and Pisum (Marks and Sachs, 1977;Sachs and Benouaiche, 1978;Kagan et al, 1992;Sachs et al, 1993;Chin et al, 1995). In Tradescantia and Pisum, arrested stomatal initials switch pathways and acquire the characteristics of epidermal cells (Kagan et al, 1992;Boetsch et al, 1995).…”

“…Furthermore, patterning mistakes, such as adjacent meristemoids, have been observed. These may be corrected by either oriented asymmetric divisions or de/redifferentiation (Geisler et al, 2000) or by the formation of arrested stomata (Sachs et al, 1993;Sachs, 1994;Chin et al, 1995). Therefore, it is likely that cell-cell interactions play an additional important role in the formation of the final stomatal pattern.…”

Blue light inhibits stomatal development in soybean isolines containing kaempferol‐3‐O‐2G‐glycosyl‐gentiobioside (K9), a unique flavonoid glycoside

“…The smallest central cell probably represents the mother cell or precursor of the guard cell that failed to complete a final cell division. This cell pattern is easily identified under light microscope ( Kagan & Sachs 1991; Chin et al 1995 ) and is considered to represent arrested stomatal development, since fully matured leaves were examined and no further cell development was expected. Other stomatal complexes had guard cells that were distinct from subsidiary cells, but which did not appear fully formed or functional (i.e.…”

“…The following information about formation of the stomatal apparatus has been established (see recent reviews Chin et al 1995 ; Larkin et al 1997 ). First, the distribution of stomata over a leaf surface is not random.…”

TOO MANY MOUTHS promotes cell fate progression in stomatal development of Arabidopsis stems

“…Stomatal precursor cell arrests have also been documented in leaves of wild-type plants of various species (Kagan et al 1992;Sachs et al 1993;Boetsch et al 1995;Chin et al 1995). Some arrests take place after precursor cells form adjacent to each other (Sachs 1991;Geisler et al 2000).…”