Taxonomic Demarcation of Setaria pumila (Poir.) Roem. & Schult., S. verticillata (L.) P. Beauv., and S. viridis (L.) P. Beauv. (Cenchrinae, Paniceae, Panicoideae, Poaceae) From Phytolith Signatures

Abstract

Background and Aims: The role and significance of phytoliths in taxonomic diagnosis of grass species has been well documented with a focus on the types found in foliar epidermis and the synflorescence. The present paper is an attempt to broaden the scope of phytoliths in species diagnosis of grasses by developing phytolith signatures of some species of the foxtail genus Setaria P. Beauv. through in situ location and physico-chemical analysis of various phytolith morphotypes in different parts of the plant body.Methods: Clearing solution and dry ashing extraction methods were employed for in situ location and isolation of phytolith morphotypes respectively. Ultrastructural details were worked out by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy. Morphometric and frequency data of phytolith morphotypes were also recorded. Biochemical architecture of various phytolith types was worked out through SEM-EDX, XRD, and FTIR analysis. Data were analyzed through Principal Component Analysis and Cluster Analysis.Key Results: In situ location of phytoliths revealed species specific epidermal patterns. The presence of cystoliths (calcium oxalate crystals) in the costal regions of adaxial leaf surface of S. verticillata (L.) P. Beauv. is the first report for the genus Setaria. Our results revealed marked variations in epidermal ornamentation and undulation patterns with a novel “Λ” (Lamda) type of undulated ornamentation reported in S. verticillata. Dry ashing method revealed species specific clusters of phytolith morphotypes.Conclusions: The study revealed that phytoliths can play a significant role in resolution of taxonomic identity of three species of Setaria. Each species was marked out by a unique assemblage of phytolith morphotypes from various parts of the plant body. Apart from in situ location and epidermal patterning, diagnostic shapes, frequency distribution, size dimensions, and biochemical architecture emerged as complementary traits that help in developing robust phytolith signatures for plant species.

A microbotanical and microwear perspective to plant processing activities and foodways at Neolithic Çatalhöyük

“…Long (elongate lobated) and short (crosses) cell phytoliths from Panicoideae were also observed together with silica skeletons with long cells with Ո and ƞ ornamentations. These types of ornamentation are normally found in Panicoideae and other C₄ grasses inflorescence [ 47 , 177 – 180 ] and more specifically Setaria verticillata ( Fig 10 ). For this reason, we made morphometric comparisons (based on characters from Zhang et al [ 125 ] between Ո patterns from modern Setaria verticillata from our reference collection and the recovered archaeological material showing similar patterns.…”

Multi-omics intervention in Setaria to dissect climate-resilient traits: Progress and prospects

“… Desai et al (2018) established S. viridis as a model system to uncover the mechanism underlining the Time of Day of Anther Appearance (TAA) regulation. In situ localization study of phytoliths exhibited species-specific morphotypes in different tissues of Setaria species that could be used for taxonomic characterization of Setaria ( Bhat et al, 2018 ). Root microbiome examination of foxtail millet plants sampled from two geographically isolated locations indicated that the host plant assists the growth of specific bacteria in the rhizosphere ( Jin et al, 2017 ).…”

Morphological diversity of phytolith structures in six species of Carex L. and Cyperus L. (Cyperaceae Juss.) from West Bengal, India

“…Netolitsky (1929) revised phytolith morphotypes and attempted to identify marker phytolith morphotypes in different taxa of flowering plants. Subsequently, phytolith characteristics were used effectively by several authors in the characterization and identification of different members of grasses (Rosen 1992;Wang and Lu 1993;Pearsall et al 1995;Houyouan et al 1997;Zhao et al 1998;Fahmy 2008;Shakoor et al 2014), Mudassir et al (2018) effectively and efficiently used phytolith signatures (elemental composition) to identify three species of Setaria (Poaceae), Prychid et al (2004) summarized the silica morphotypes in the tribe Cypereae of the subfamily Cyperoideae and in the tribe Cariceae of the subfamily Caricoideae. Though, Muasya et al (2009) divided the family Cyperaceae into two subfamilies: Cyperoideae and Mapanioideae, based on molecular data.…”