Photo credit: NCBI
Modified stomata in wild type Arabidopsis.
(A) Cryoscanning electron micrograph showing stomata at the tips of nectaries (Nadeau and Sack, 2002a).
(B) DIC image of a hydathode. Arrowheads indicate modified stomata with large open pore in contact with one another.
Scale bar 30µm (A) and 10µm (B).
Stomatal Development in Arabidopsis
by Pillitteri L. J., Dong J. (2013)
in The Arabidopsis Book, vol. 11, pp. e0162, June 2013. – doi: 10.1199/tab.0162 –
Stomata consist of two guard cells that function as turgor-operated valves that regulate gas exchange in plants. In Arabidopsis, a dedicated cell lineage is initiated and undergoes a series of cell divisions and cell-state transitions to produce a stoma.
A set of basic helix-loop-helix (bHLH) transcription factors regulates the transition and differentiation events through the lineage, while the placement of stomata relative to each other is controlled by intercellular signaling via peptide ligands, transmembrane receptors, and mitogen-activated protein kinase (MAPK) modules.
Some genes involved in regulating stomatal differentiation or density are also involved in hormonal and environmental stress responses, which may provide a link between modulation of stomatal development or function in response to changes in the environment.
Premitotic polarly localized proteins provide an added layer of regulation, which can be addressed more thoroughly with the identification of additional proteins in this pathway.
Linking the networks that control stomatal development promises to bring advances to our understanding of signal transduction, cell polarity, and cell-fate specification in plants.