Plasticity in stomatal development and stomatal conductance as influenced by stomatal ratio and growth habitat
Auker, Emily Jane
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While the impact of what environmental conditions promote amphistomy or hypostomy is extensively recorded, the impact on stomatal anatomy and function in amphistomatous versus hypostomatous plants is poorly quantified. The objective of this study was to test two hypotheses: (H1) amphistomatous species have greater stomatal developmental plasticity in response to local environmental conditions than hypostomatous species, as demonstrated by anatomical measurements of stomatal density, size, and maximum potential conductance (gsmax); and (H2) the increased developmental plasticity associated with amphistomy will enable greater flexibility in operational conductance (gs) over the course of a growing season. Species pairs, with one amphistomatous and one hypostomatous species, in the genera Aralia, Populus, and Salix were found through an initial survey at the Arnold Arboretum of Harvard University in Boston, Massachusetts. The above anatomical and physiological variables were measured, and it was found that the first hyposthesis was supported by the results while the second hypothesis was not. Overall, this indicates that amphistomatous species have enhanced developmental plasticity but that plasticity does not extend to physiological performance. This opens up further areas of study in order to determine what other environmental factors or leaf traits impact gs.