How are Systematics and Biological and Ecological Features Related to Silica Content in Plants?: A Study in Species from the Southern of South America

HONAINE, MARIANA FERNÁNDEZ; BENVENUTO, M. LAURA; MONTTI, LÍA; NATAL, MARCELA; BORRELLI, NATALIA L.; ALVAREZ, M. FERNANDA; ALTAMIRANO, STELLA MARIS; RITO, MARA DE; OSTERRIETH, MARGARITA L.

INTERNATIONAL JOURNAL OF PLANT SCIENCES

UNIV CHICAGO PRESS

Año: 2020

1058-5893

Premise of the Research: Plant silica content depends on the phylogenetic position of a taxon;however, biological or ecological factors may also affect it. In this work, we analyzed data aboutsilicophytolith content from 105 species of South America, examining, in a phylogenetic context, itsrelationship with the anatomy and ecological features such as life cycle, growth form, plant originand environmental preferences.Methodology: Data about silicophytolith content and bio-ecological features of the species wereobtained from published and unpublished sources. The relation between systematics, silica contentand bio-ecological variables were analyzed through measurements of phylogenetic signal andphylogenetic generalized least-squares regressions (PGLS).Pivotal Results: 86% of the species produced between 0.38% and 19% dry weight ofsilicophytoliths in leaves. Silica content was variable between and within clades. λ and K valuesindicate a low phylogenetic signal for the variable silica content. Dicotyledons accumulated silica intypical epidermal cells, and a few families stored it also in cystoliths. Most of the monocot familiesshowed high silicophytolith contents and high diversity of silicified cells. Plant origin affected silicacontents: exotic species accumulated more than native ones. On the other hand, no statisticalrelationship was found between silica content and the other ecological variables.Conclusions: Silicophytolith accumulation is a common feature in most of the species studied. Thelow phylogenetic signal of silica content is explained by the inter and intra clade variability, whichin turn support the hypothesis that silicophytolith accumulation is a homoplasic character amongplants. Based on the overall analysis of the silicophytolith content and their tissue distribution, highcontent could be related to specific accumulation mechanisms and roles of silica. The origin of theplants was the only bio-ecological variable that influenced in plant silica content. This finding mayindicate some ecological role of silica in exotic plants, involving the success of them in novelenvironments.