Phytoliths as a method of identification for three genera of woody bamboos (Bambusoideae) in tropical southwest China

In order to explore the relation between phytolith morphology and plant taxonomy, we conducted a comparative research on the morphological features of phytoliths from 26 woody bamboo species within 3 genera of Bambusoideae in tropical southwest China. All morphological parameters were measured at 500× magnification using an Olympus BX51 light microscope. Three-dimensional scattered plots and hierarchical cluster analysis were performed using SPSS 13.0 software. The leaves of woody bamboos contain a great diversity of phytolith types including short cells, long cells, bulliform cells, hair cells, mesophyll and vascular tissues, of which cuneiform bulliform cells and oblong concave saddles were significant in clarifying the position of controversial Dendrocalamopsis group. Detailed research on phytolith morphology demonstrated that most of the overlap within this group occurs among long cells, bilobates, parallepipedal bulliform cells, hair cells, mesophyll and vascular tissues at the genus level. Oblong concave saddles exhibited taxonomical value both at the subfamily and genus levels. Comparative research on the morphological parameters of cuneiform bulliform cells and oblong concave saddles indicated Dendrocalamopsis has a separate partition from Bambusa and Dendrocalamus, which might provide strong evidence that Dendrocalamopsis should be an independent genus within Bambusoideae. Hierarchical cluster analysis on the cuneiform bulliform cells and oblong concave saddles indicated that Dendrocalamopsis is more closely related to Bambusa than Dendrocalamus. At the genus level, cuneiform bulliform cells and oblong concave saddles together exhibit taxonomical value.