Differences in stomatal conductance between leaf shape genotypes of Ipomoea hederacea suggest divergent ecophysiological strategies

TL;DR

Different leaf shapes in Ipomoea hederacea affect how plants manage water and temperature, possibly influencing where they grow best.

Contribution

The study reveals how leaf shape variation in a species correlates with stomatal conductance and water use strategies.

Findings

Entire leaf genotypes showed higher stomatal conductance in warm and sunny conditions.

Lobed genotypes may be better adapted to drier environments due to reduced water loss.

Lobed genotypes are more common in drier northern regions of the species' range.

Abstract

Intraspecific variation in leaf shape affects many physiological processes but its impact on plant distribution is underexplored. Using a common garden, we studied daytime thermoregulation of lobed and entire leaf genotypes of
Ipomoea hederacea,
which displays a latitudinal leaf shape cline. Both leaf shapes maintained similar temperatures but entire leaf genotypes had significantly increased stomatal conductance in warmer/sunnier weather. With less potential water loss, lobed genotypes may have advantages in drier conditions. Lobed genotypes are more common in the north of the species' range, which receives less summer precipitation, suggesting water availability as a potential clinally varying selective agent.

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