Abstract
Hydathodes are usually associated with water exudation in plants. However, foliar water uptake (FWU) through the hydathodes has long been suspected in the leaf-succulent genus Crassula (Crassulaceae), a highly diverse group in southern Africa, and, to our knowledge, no empirical observations exist in the literature that unequivocally link FWU to hydathodes in this genus. FWU is expected to be particularly beneficial on the arid western side of southern Africa, where up to 50% of Crassula species occur and where periodically high air humidity leads to fog and/or dew formation. To investigate if hydathode-mediated FWU is operational in different Crassula species, we used the apoplastic fluorescent tracer Lucifer Yellow in combination with different imaging techniques. Our images of dye-treated leaves confirm that hydathode-mediated FWU does indeed occur in Crassula and that it might be widespread across the genus. Hydathodes in Crassula serve as moisture-harvesting structures, besides their more common purpose of guttation, an adaptation that has likely played an important role in the evolutionary history of the genus. Our observations suggest that ability for FWU is independent of geographical distribution and not restricted to arid environments under fog influence, as FWU is also operational in Crassula species from the rather humid eastern side of southern Africa. Our observations point towards no apparent link between FWU ability and overall leaf surface wettability in Crassula. Instead, the hierarchically sculptured leaf surfaces of several Crassula species may facilitate FWU due to hydrophilic leaf surface microdomains, even in seemingly hydrophobic species. Overall, these results confirm the ecophysiological relevance of hydathode-mediated FWU in Crassula and reassert the importance of atmospheric humidity for some arid-adapted plant groups.
Originalsprog | Engelsk |
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Tidsskrift | Plant Cell and Environment |
Vol/bind | 47 |
Udgave nummer | 2 |
Sider (fra-til) | 460-481 |
ISSN | 0140-7791 |
DOI | |
Status | Udgivet - 2024 |
Bibliografisk note
Funding Information:The authors would like to thank Theodor E. Bolsterli, Monika Dragsted, Jan Hostrup, Morten L. Stephensen and other members of the plant facilities team at PLEN (University of Copenhagen) for assistance while growing the plants in the greenhouse and climate chamber. We would also like to thank Catherine S. Nielsen and Sebastian Kjeldgaard‐Nintemann from the Center for Advanced Bioimaging (CAB, University of Copenhagen), and Klaus Qvortrup from the Core Facility for Integrated Microscopy (CFIM, University of Copenhagen), for invaluable help during sample preparation and imaging. Finally, we would like to thank Petr Pavelka for sharing the images of subsp. growing in the wild shown in Figure 2 . This project was funded by the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska‐Curie Grant agreement No 801199. This project was also supported by the Grønt Udviklings‐ og Demonstrationsprogram (GUDP, GræsProteinFoder project). JM was supported by a grant from Slovak Academy of Sciences (project number IM‐2021‐23). C. ausensis titanopsis
Publisher Copyright:
© 2023 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.