Poster 229 – Click on poster below to view presentation from author.
University of Louisiana at Lafayette
Co-Authors: Robert Bordelon, Jorge Villa
Wetlands are the largest natural source of methane emissions, and most of those emissions are mediated by plants. Understanding emission fluxes in relation to phenological changes is essential for accurate methane budgets and predictions. To this purpose, we designed a field experiment to explore the correlation between senescence and methane fluxes, including the design of a custom-made, clear chamber to measure individual foliar methane fluxes. In this study, we tested if chamber deployment during methane flux measurements affects stomatal conductance in southern cattails (Typha domingensis). Accordingly, we measured stomatal conductance before and after 3-minute chamber deployment on different leaves, accounting for different locations and positions on the leaves, during four sampling days. We used a portable leaf porometer (SC-1 Meter ®) that recorded stomatal conductance, leaf relative humidity, and leaf temperature. Our results show that conductance and leaf relative humidity was not significantly different between measurements conducted before and after chamber deployments (Wilcoxon Sign tests, p > 0.05), except for one sampling day. Meteorological conditions during this sampling were dominated by a moderate breeze and permanent passing clouds, which resulted in constant changing overcast conditions, which ultimately may have affected conductance beyond the chamber effect. Leaf temperatures were not significantly affected by chamber deployments any sampling campaigns. Changes in stomatal conductance were observed to be more directly correlated to changes in leaf relative humidity than it was to changes in leaf temperature. We conclude that the custom-made chamber does not generate significant physiological disturbances for leaves in short periods of use under consistent weather conditions, and it is a reliable method for leaf-level methane fluxes in southern cattails.
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