There are differences between sexes in physiological and functional traits and possibly in nutrient resorption, particularly in nutrient‐poor environments. However, little is known about the extent of nutrient resorption from fine stems and fine roots, and about how nutrient resorption is related to leaf economics in the males and females of dioecious trees. We investigated nutrient resorption of different organs and explored whether nutrient resorption is associated with nutrient conservation traits of leaves (e.g. leaf thickness, leaf mass per area, LMA) in Populus euphratica females and males in four natural forests along the Tarim River, China. Both female and male leaves had the highest N resorption efficiency (NRE), than stems and roots. We found sexual dimorphism in leaf nutrient resorption at Shaya, Luntai and Yuli forest sites, where P. euphratica males had higher leaf NRE than females, whereas females had a higher leaf P resorption efficiency (PRE). Moreover, the different nutrient resorption strategies were related to leaf economics. P. euphratica males possess a conservation strategy with a higher leaf thickness, LMA and leaf vein density, which positively correlated with leaf NRE, while females with higher leaf PRE resorbed disproportionately more P for the reproductive investment. Synthesis. Populus euphratica males possess a conservation strategy with higher leaf NRE, while females have higher leaf PRE for the reproductive investment. Due to spatial sexual segregation across environmental gradients, dioecious plants are especially vulnerable under future climate change. The differences in nutrient uptake and utilization strategies between females and males may result in a situation where one sex is more prone to future climate change than the other one. Such sex‐specific nutrient resorption strategies are associated with leaf economics. The present study deepens our understanding of the nutrient balance and adaptation strategies of plants under climate change.
The continuously increasing atmospheric carbon dioxide concentration ([CO2]) has substantial effects on plant growth, and on the composition and structure of forests. However, how plants respond to elevated [CO2] (e[CO2]) under intra- and interspecific competition has been largely overlooked. In this study, we employed Abies faxoniana Rehder & Wilson and Picea purpurea Mast. seedlings to explore the effects of e[CO2] (700 p.p.m.) and plant–plant competition on plant growth, physiological and morphological traits, and leaf ultrastructure. We found that e[CO2] stimulated plant growth, photosynthesis and nonstructural carbohydrates (NSC), affected morphological traits and leaf ultrastructure, and enhanced water- and nitrogen (N)- use efficiencies in A. faxoniana and P. purpurea. Under interspecific competition and e[CO2], P. purpurea showed a higher biomass accumulation, photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies compared with A. faxoniana. However, under intraspecific competition and e[CO2], the two conifers showed no differences in biomass accumulation, photosynthetic capacity, and water- and N-use efficiencies. In addition, under interspecific competition and e[CO2], A. faxoniana exhibited higher NSC levels in leaves as well as more frequent and greater starch granules, which may indicate carbohydrate limitation. Consequently, we concluded that under interspecific competition, P. purpurea possesses a positive growth and adjustment strategy (e.g. a higher photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies), while A. faxoniana likely suffers from carbohydrate limitation to cope with rising [CO2]. Our study highlights that plant–plant competition should be taken into consideration when assessing the impact of rising [CO2] on the plant growth and physiological performance.
Although many studies have evaluated plant eco-physiological responses to increasing atmospheric carbon dioxide concentration (CO2) and increasing temperature, few studies have addressed the interactive effects of these two factors, especially on high-altitude trees that are more sensitive. To address this, we used Abies faxoniana and Picea purpurea seedlings to evaluate the effects of elevated CO2 (CeTa, 700 ppm), elevated temperature (CaTe, 2 °C above ambient temperature), and elevated CO2 combined with elevated temperature (CeTe) on plant growth, morphology, and physiological responses. We found that CaTe increased both conifer total dry mass, specific root length, net photosynthesis rate and translocation rates of 15NH4 + and 15NO3 –, but CeTe had stronger responses (except net photosynthesis rate of A. faxoniana). These results indicate that the effect of elevated temperature on the growth and physiological responses is enhanced by elevated CO2. Furthermore, effect of CeTe on physiological traits was higher in P. purpurea, which possessed a higher total dry mass, specific leaf area, water use efficiency (δ 13C), δ 15NO3 –-N level, translocation rates of 15NH4 + and 15NO3 – and total non-structural carbohydrates than A. faxoniana. Overall, these findings suggest that the interactive effects of CO2 × temperature should be considered when assessing conifer responses to future climates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.