Stomatal responses to changes in humidity in desert plants


Photo credit: Google

Patio Apricot Tree – Super Mini Prunus armeniaca

Stomatal responses to changes in humidity in plants growing in the desert.

by Schulze E. D., Lange O. L., Buschbom U., Kappen L.,  Evenari M. (1972)

in Planta 108 : 259–270  – oi: 10.1007/BF00384113. –

[PubMed – Google Scholar) –

Photo credit Google – Hammada scoparia –


The stomata of plants growing in the Negev Desert, namely the stomata of the mesomorphic leaves of Prunus armeniaca, the xeromorphic stems of Hammada scoparia, and the succulent leaves of Zygophyllum dumosum, respond to changes in air humidity.

Photo credit Google – Zygophyllum dumosum –

Under dry air conditions diffusion resistance increases. Under moist air conditions diffusion resistance decreases. When the stomata close at low air humidity the water content of the apricot leaves increases.

The stomata open at high air humidity in spite of a decrease in leaf water content. This excludes a reaction via the water potential in the leaf tissue and proves that the stomatal aperture has a direct response to the evaporative conditions in the atmosphere.

In all species the response to air humidity is maintained over a period of many hours also when the soil is considerably dry. The response is higher in plants with poor water supply then in well watered plants.

Thus for field conditions and for morphologically different types of photosynthesizing organs the results confirm former experiments carried out with isolated epidermal strips.


Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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