Quantifying the effect of shade on cuticle morphology and carbon isotopes of sycamores: present and past

Autor: Jennifer D. Wagner, Bernd Zechmann, Andrew Flynn, Joseph Milligan, Joseph White, Daniel J. Peppe, Lenny L.R. Kouwenberg, Bruce W. Byars, Richard S. Barclay, Regan E. Dunn
Rok vydání: 2021
Předmět:
Zdroj: American Journal of Botany. 108:2435-2451
ISSN: 1537-2197
0002-9122
DOI: 10.1002/ajb2.1772
Popis: PREMISE Reconstructing plant canopy light environment and architecture from the fossil record includes proxies derived from cell wall undulation, cell size, and carbon isotopes. All approaches assume that plant taxa will respond predictably to changes in light environments. However, most species-level studies looking at cell wall undulation only consider "sun" or "shade" leaves, therefore we lack a fully quantitative taxon-specific method. METHODS We quantify the response of cell wall undulation, cell size, and carbon isotopes of Platanus occidentalis using two different experimental setups: (1) two growth chambers at low and high light and (2) a series of outdoor growth experiments using green and black shade cloth at different densities. We then developed and applied a proxy for daily light integral (DLI) to fossil Platanites leaves from two early Paleocene floras from the San Juan Basin in New Mexico. RESULTS All traits responded to light environment. Cell wall undulation was the most useful trait for reconstructing DLI in the geological record. Median reconstructed DLI from early Paleocene leaves was ~44 mol m-2 d-1, with values ranging from 28 - 54 mol m-2 d-1. CONCLUSIONS Cell wall undulation of P. occidentalis is a robust, quantifiable measurement of light environment that can be used to reconstruct paleo-light environment from fossil leaves. The distribution of high DLI values from fossil leaves may provide information on canopy architecture; indicating that either (1) most of the canopy mass is within the upper portion of the crown or (2) leaves exposed to more sunlight are preferentially preserved. This article is protected by copyright. All rights reserved.
Databáze: OpenAIRE
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