Charlotte Prieu1, Alexis Matamoro-Vidal2, Christian Raquin3, Anna Dobritsa4, Raphaël Mercier5, Pierre-Henri Gouyon6, Béatrice Albert3. 1. Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay cedex, France CNRS, Orsay F-91405, France Institut de Systématique, Évolution, Biodiversité, ISYEB-UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP39, F-75005, Paris, France charlotte.prieu@u-psud.fr. 2. Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay cedex, France CNRS, Orsay F-91405, France Institut de Systématique, Évolution, Biodiversité, ISYEB-UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP39, F-75005, Paris, France. 3. Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91405 Orsay cedex, France CNRS, Orsay F-91405, France. 4. Department of Molecular Genetics and Center for Applied Plant Sciences, The Ohio State University, 015 Rightmire Hall, 1060 Carmack Road, Columbus, Ohio 43210 USA. 5. INRA, UR254, IJPB, Versailles, France. 6. Institut de Systématique, Évolution, Biodiversité, ISYEB-UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP39, F-75005, Paris, France.
Abstract
PREMISE OF THE STUDY: Pollen grains are subject to intense dehydration before dispersal. They rehydrate after landing on a stigma or when placed in humid environment by absorbing water from the stigma or surroundings. Resulting fluctuations in water content cause pollen grains to undergo significant changes in volume. Thus, morphological or structural adaptations might exist to help pollen adjust to sudden volume changes, though little is known about the correlation between pollen morphology and its ability to accommodate volume changes. We studied the effect of one morphological feature of pollen grains, the aperture number, on pollen wall resistance to water inflow in Arabidopsis thaliana. METHODS: We used three Arabidopsis thaliana mutants that differ in the number of apertures in their pollen (zero, four, or a mix of four to eight, respectively) and the wild type with pollen with three apertures. We tested pollen survival in solutions with various mannitol concentrations. KEY RESULTS: The number of intact pollen grains increased with increasing mannitol concentration for all pollen morphs tested. At a given mannitol concentration, however, an increase in aperture number was associated with an increase in pollen breakage. CONCLUSIONS: Aperture patterns, i.e., number, shape, and position, influence the capacity to accommodate volume variations in pollen grains. When subjected to water inflow, pollen grains with few apertures survive better than pollen with many apertures. Trade-offs between survival and germination are likely to be involved in the evolution of pollen morphology.
PREMISE OF THE STUDY: Pollen grains are subject to intense dehydration before dispersal. They rehydrate after landing on a stigma or when placed in humid environment by absorbing water from the stigma or surroundings. Resulting fluctuations in water content cause pollen grains to undergo significant changes in volume. Thus, morphological or structural adaptations might exist to help pollen adjust to sudden volume changes, though little is known about the correlation between pollen morphology and its ability to accommodate volume changes. We studied the effect of one morphological feature of pollen grains, the aperture number, on pollen wall resistance to water inflow in Arabidopsis thaliana. METHODS: We used three Arabidopsis thaliana mutants that differ in the number of apertures in their pollen (zero, four, or a mix of four to eight, respectively) and the wild type with pollen with three apertures. We tested pollen survival in solutions with various mannitol concentrations. KEY RESULTS: The number of intact pollen grains increased with increasing mannitol concentration for all pollen morphs tested. At a given mannitol concentration, however, an increase in aperture number was associated with an increase in pollen breakage. CONCLUSIONS: Aperture patterns, i.e., number, shape, and position, influence the capacity to accommodate volume variations in pollen grains. When subjected to water inflow, pollen grains with few apertures survive better than pollen with many apertures. Trade-offs between survival and germination are likely to be involved in the evolution of pollen morphology.
Authors: Béatrice Albert; Adrienne Ressayre; Christine Dillmann; Ann L Carlson; Robert J Swanson; Pierre-Henri Gouyon; Anna A Dobritsa Journal: Ann Bot Date: 2018-03-14 Impact factor: 4.357