Authors:

Connor Baker

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About Paper:

To survive a drought, plants are tasked with limiting water loss while maintaining efficient metabolic activity. Stomata, or adjustable pores embedded in the epidermis of leaves, account for upwards of 90% of all evapotranspiration and as such their closure is pivotal to ensure survivability when water is scarce. During a drought abscisic acid is synthesized within the leaf to reduce the degree of stomatal aperture. During these periods of stress, water is still lost through incompletely closed stomata, the cuticle, and the periderm; a process termed minimum or residual conductance. It is currently unknown how climatic variables like precipitation, temperature, and relative humidity - vapor pressure deficit - affect a species rate of minimum conductance. Here we show, in the field, the effect of intermittent drought periods subsequently followed by rainfall events on a species minimum conductance during the months of June and July in two co-occurring deciduous trees, Tilia americana and Fagus grandifolia. Our results suggest that precipitation and vapor pressure deficit do not directly affect a species minimum conductance. Throughout the duration of the experiment T. americana exhibited no significant changes in minimum conductance while F. grandifolia exhibited minor changes in minimum conductance that were not correlated with precipitation or vapor pressure deficit. Interestingly, the proportion of water lost through residual pathways did change in response to fluctuations in abscisic acid concentrations. These findings suggest that a species cuticular and bark permeance may be key limiting factors to survival during drought. (Work in progress)

Source:

Purdue University / 2023

Topics:

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Co-authors:

Connor Baker