Differences in growth and physiological traits of Populus cathayana populations as affected by enhanced UV-B radiation and exogenous ABA

摘要: During one growing season, the effects of enhanced ultraviolet-B (UV-B) radiation, exogenous abscisic acid (ABA) and their combination on biomass accumulation, gas exchange, endogenous ABA, concentration UV-absorbing compounds, antioxidant system carbon (C) nitrogen (N) content C/N ratio were investigated in two contrasting Populus cathayana Rehd. populations, originating from high low altitudes south-west China. Exogenous ABA was sprayed to leaves, UV-B treatments applied using a square-wave expose seedlings ambient (I x) or twice (2x) doses biologically effective radiation (UV-B-BE). Enhanced significantly decreased height, basal diameter, total leaf area, biomass, net CO2 assimilation rate (A). stomata[ conductance (g,). transpiration (E) leaves. increased activities superoxide dismutase (SOD) guaiacol peroxidase (GPx), contents hydrogen peroxide (H2O2) malonaldehyde (MDA). as well accumulation compounds concentrations among different organs both populations. In contrast, induced significant decrease A increases SOD GPx, H2O2 MDA. concentrations. Compared with altitude population, population more tolerant ABA. Significant interactions between observed A, E, leaves roots Across all treatments, C N strongly correlated stems roots. Additionally, stems. (c) 2008 Elsevier B.V. All rights reserved.