Stomata in Bryophytes
by Randall J. M., McAdam S. (2019)
Randall Joshua M. , McAdam Scott .
1 – Purdue University, Botany and Plant Pathology, 915 W State St, West Lafayette, Indiana, 47907, United States
2 – Purdue University, 915 W State St, West Lafayette, Indiana, 47907, United States
In Botany 2019 –
Bryophytes, including mosses, are the oldest living group of land plants; therefore, they can be used to understand the origins of the organs that allowed the colonization of land.
Stomata are small openings found on the leaves of vascular plants to allow for water and carbon dioxide transfer, but in bryophytes the sexual organ, or sporophyte, has been found to also have stomata.
Using collected mosses from central Indiana, this study is intended to determine the presence of stomata across different moss lineages and their anatomy.
Mosses were keyed out using a dichotomous key according to gametophyte characteristics, and stomata were examined using a compound microscope to determine size and shape. Afterwards, a simple parsimony tree was created using this information to determine when stomata likely evolved.
Additional genomic information was collected from the 1000 Plant Project and BLASTPed against the SPEECHLESS (SPCH) transcription factor in Arabidopsis thaliana to find species across all lineages with similar proteins.
The SPCH transcription factor has been confirmed to allow for the development of guard cells that form stomata, and its presence in various moss lineages was used to build another phylogenetic tree.
Together, the physiological information and genomic analysis support the theory that modern stomata originated in non-vascular plants, but the history appears to be more complicated than previously thought.
Stomata are present in numerous lineages of moss with varying amino acid content and structures. The hypothesis of multiple losses and gains across mosses was not disproven.