Affordable Access

deepdyve-link
Publisher Website

Root vascular traits differ systematically between African savanna tree and grass species, with implications for water use.

Authors
  • Wargowsky, Isabel K1
  • NeSmith, Julienne E1
  • Holdo, Ricardo M1, 2
  • 1 Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA. , (Georgia)
  • 2 School of Animal Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, 2050, South Africa. , (South Africa)
Type
Published Article
Journal
American Journal of Botany
Publisher
Wiley (John Wiley & Sons)
Publication Date
Jan 01, 2021
Volume
108
Issue
1
Pages
83–90
Identifiers
DOI: 10.1002/ajb2.1597
PMID: 33450049
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Belowground functional traits play a significant role in determining plant water-use strategies and plant performance, but we lack data on root traits across communities, particularly in the tropical savanna biome, where vegetation dynamics are hypothesized to be strongly driven by tree-grass functional differences in water use. We grew seedlings of 21 tree and 18 grass species (N = 5 individuals per species) from the southern African savanna biome under greenhouse conditions and collected fine-root segments from plants for histological analysis. We identified and measured xylem vessels in 539 individual root cross sections. We then quantified six root vascular anatomy traits and tested them for phylogenetic signals and tree-grass differences in trait values associated with vessel size, number, and hydraulic conductivity. Grass roots had larger root xylem vessels than trees, a higher proportion of their root cross-sectional area comprised vessels, and they had higher estimated axial conductivities than trees, while trees had a higher number of vessels per root cross-sectional area than grasses did. We found evidence of associations between trait values and phylogenetic relatedness in most of these traits across tree species, but not grasses. Our findings support the hypothesis that grass roots have higher water transport capacity than tree roots in terms of maximum axial conductivity, consistent with the observation that grasses are more "aggressive" water users than trees under conditions of high soil moisture availability. Our study identifies root functional traits that may drive differential responses of trees and grasses to soil moisture availability. © 2021 Botanical Society of America.

Report this publication

Statistics

Seen <100 times