Phytoliths in Inflorescence Bracts: Preliminary Results of an Investigation on Common Panicoideae Plants in China.

Yong Ge,Can Wang,Jianping Zhang,Xing Gao,Houyuan Lu

doi:10.3389/fpls.2019.01736

Abstract

Phytoliths in the inflorescence of Poaceae plants can be of high taxonomic value in some archaeological contexts and provide insight into plant taxonomy and crop domestication processes. In this study, phytoliths in every inflorescence bract of 38 common Panicoideae weeds and minor crops in China were studied. Based on dissection of the inflorescence into different bracts using a treatment that retained the phytoliths anatomical position, observations of inflorescence phytoliths types and distribution were described in detail. We found that Interdigitating, Blocky amoeboid, Rectangular dentate, and Elongate dendritic with multi tent-like arch tops were of higher taxonomic value than the other types in our studied species. Both morphological and morphometric traits of the Interdigitating were summarized and compared with previous studies; the findings suggested that genus level discrimination of some Paniceae species could be reliable, and tribe/species level discrimination might be feasible. The phytoliths in the involucre of domesticated and wild type Coix lacryma-jobi provided insight into the domestication process of this plant. Our data also indicated that phytolith production in the inflorescence bracts might be under the genetic and molecular control of inflorescence development. Thus, the findings of this study could assist future studies in plant taxonomy and archaeobotany.

Highlights

Phytoliths are plant-produced micro silica bodies which can, in some cases, have a diagnostic morphology that can be distinguished among taxa; in particular, phytoliths in the Poaceae family can have taxonomic value in archaeological contexts and natural sediments (Twiss et al, 1969; Wang and Lu, 1993; Piperno, 2006)
The distribution of phytolith types in the inflorescence bracts are shown in Table 3, detailed descriptions can be found in the Supplementary file, and the details of phytolith morphology in different inflorescence bracts can be found in Supplementary Figures 1–9
Elongate phytoliths were classified into Elongate entire, Elongate dendritic/dentate, Elongate entire cylindric, Elongate dentate cylindric, and Elongate phytoliths with a special 3-D morphology were observed in some specimens; the 3-D morphology was described following previously published methods (Piperno and Pearsall, 1993): first, according to the morphology of the base (e.g. Elongate dendritic/dentate base), according to the morphology of the top

Summary

Introduction

Phytoliths are plant-produced micro silica bodies which can, in some cases, have a diagnostic morphology that can be distinguished among taxa; in particular, phytoliths in the Poaceae family can have taxonomic value in archaeological contexts and natural sediments (Twiss et al, 1969; Wang and Lu, 1993; Piperno, 2006). Many other wild relatives and minor crops have not been studied, which results in identification uncertainty, and has stalled further application of phytolith analysis in the investigation of early plant resource exploitation

Methods

Results

Discussion

Conclusion