Exploring adaptive modulation in plant functional traits and its impact on the productivity of Acacia auriculiformis under CO2-enriched environment

Abstract

The present study aims to assess the influence of CO2-enriched (600 ± 10,800 ± 14, 1000 ± 18 and 1200 ± 24 μmol CO2 mol−1) and ambient environment (400 ± 5 μmol CO2 mol−1) on modulation in plant functional traits and their impacts on carbon allocation and productivity of Acacia auriculiformis. The findings revealed that physiological traits, mainly CO2 assimilation, transpiration, stomatal conductance, and water use efficiency, were significantly modulated under CO2 enrichment than ambient. Leaf biochemical traits (total chlorophyll, chlorophyll a, b, a/b, carotenoids, sugars, and proline) were significantly affected by CO2 enrichment. Furthermore, elevated CO2 significantly changed the nutrient concentration (nitrogen, phosphorus, potassium, and carbon) in the leaf, stem, and root, considerably reducing nitrogen content compared to ambient. Growth traits, particularly leaf area, specific leaf area, leaf area ratio, net assimilation rate, absolute growth rate, and leaf mass ratio, exhibited improvement under CO2-enriched environment, with variations in response observed at different CO2 concentrations. Carbon allocation in leaf, stem, root, shoot, total biomass production, and the root-to-shoot ratio exhibited significant enhancements under the CO2-enriched environment. A significant correlation was observed between the plant functional traits and biomass production of A. auriculiformis. The study suggests that enhancing scientific understanding of functional traits and their influence on biomass production may contribute to a more robust comprehension of how plantation species may adapt in future CO2-enriched environments projected by the IPCC. Therefore, it is crucial to conduct long-term studies to comprehend the adaptive mechanisms of plantation species to elevated CO2 and other environmental variables, such as temperature, water, and nutrients.