Philippine Journal of Science
142:(3) 245-248, Special Issue
ISSN 0031-7683
The Non-Functional Stomata on the Leaf Margin of Selaginella
Yi Youguang and Benito C. Tan
Department of Biological Sciences, National University of Singapore
Singapore 119267
ABSTRACT
Stomata are structures on the surface of leaves known for their function in gaseous exchange in plants. After examining 26 species of Selaginella collected from Peninsular Malaysia and Singapore, we discover and report the presence of stomatal structures that are located right on the border of adaxial surface of lateral and axillary leaves of four species of Selaginella (S. roxburghii, S. ridleyi, S. rivalis and S. ciliaris). The marginal stomata appear to be non-functional due to their position on the leaf border which is one to two cells thick.
INTRODUCTION
Stomata are small apertures found in the above ground parts of all terrestrial plants, especially on the leaf surfaces. They function to account for approximately 95% of gaseous exchange and regulate water loss via transpiration and CO2 uptake during photosynthesis (Taiz & Zeiger 2010, Camargo & Marenco 2011).
Selaginella are a group of Lycophyta whose diversity is still relatively not well studied in E and SE Asia. A few published keys based on morphological characters are available for the species identification in SE Asia (Alston 1934, 1935, Dahlen 1988, Wong 1983). Additionally, there were three recently conducted, albeit incomplete,
phylogenetic studies consisting of European and American species of Selaginella (Manhart 1995, Korall et al. 1999, Korall & Kenrick 2002). Much of the study of basic biology of this group of basal plant taxa in the Malesian region are still waiting and needed investigation by the
scientific community. . . . . . . read more
