Research was supported by Portland State University, the Li-COR Environment Education Fund for undergraduate research, and the National Science Foundation (DEB 0743461).
International Journal of Plant Sciences
Sex (Biology), Soil fungi, Shimeji mushrooms, Mycorrhizal fungi
Premise of research. In dioecious plant species, males and females often differ in physiology, and mycorrhizal fungal relationships are likely to inﬂuence these differences. However, few data are available on the potential role of mycorrhizal fungi in altering sex-speciﬁc physiology and population sex ratios of dioecious plant species.
Methodology. In this study, we measured leaf gas exchange in a multifactorial greenhouse experiment with and without mycorrhizal fungal additions and under ﬁeld conditions in Distichlis spicata, a dioecious C4 salt marsh grass, displaying extreme spatial sex ratio variation.
Pivotal results. We found a signiﬁcant interaction between gas exchange, plant sex, and mycorrhizal fungal infection. Speciﬁcally, females but not males had signiﬁcantly lower transpiration rates and higher water use efﬁciency (WUE) in treatments with increased mycorrhizal fungi. Additionally, ﬁeld data showed similar WUE between plants at female-majority sites and male-majority sites, despite signiﬁcantly lower rates of net assimi- lation and stomatal conductance in plants at female-majority sites.
Conclusions. Our results suggest that the higher WUE associated with increased mycorrhizal fungi in female D. spicata plants may be an important physiological attribute enabling female success in the higher-stress salt- water environment contributing to the spatial segregation of the sexes observed in this dioecious species.
Reuss-Schmidt, K., Rosenstiel, T. N., Rogers, S. R., Simpson, A. G., & Eppley, S. M. (2015). Effects of Sex and Mycorrhizal Fungi on Gas Exchange in the Dioecious Salt Marsh Grass Distichlis spicata. International Journal of Plant Sciences, 176(2), 000-000.