作者: Juan Chen, Quan Liu, Lei Yu, Helena Korpelainen, Ülo Niinemets, Chunyang Li

Abstract: It remains unclear how global climate change affects dioecious plants that may be especially vulnerable to climate drivers, because they often exhibit skewed sex ratios and eco-physiological specialization in certain microhabitats. In this study, female and male saplings of Populus cathayana were employed to explore sex-specific responses and the effects of sexual competition under elevated temperature (ET), elevated CO₂ (EC) and combination of elevated temperature and CO₂ (ETC). The results demonstrated that elevated temperature and CO₂ interactively modulated sexual competition and responses of P. cathayana. Moreover, competition patterns affected the eco-physiological responses of P. cathayana to climate change treatments. Under both intra- and inter-sexual competition, biomass components, photosynthetic parameters and carbon-related metabolites of females were most strongly affected by ET, while males exhibited a higher photosynthesis and resource use efficiency, and a better biomass accumulation and carbon balance mechanism when compared to females when experiencing intra-sexual competition under EC. The competitive pressure of females on males in inter-sexual competition was intensified by ET, while it was alleviated by ETC. We conclude that climate change drivers and competition patterns differently regulate the sex-specific responses and competitive intensity of males and females, which may have a crucial effect on sex ratios, spatial sexual segregation, biomass production and carbon sequestration in dioecious species in the future.

Keywords: Nitrogen use efficiency, Sexual competition, Climate change, Non-structural carbohydrates, Structural carbohydrates, Photosynthetic capacity

DOI: 10.1016/j.foreco.2020.118747