不同蒿属植物对光强的适应性差异研究

Photosynthetic responses to light of the four sagebrush species

关键词:  蒿属植物  非直角双曲线  光响应曲线  适应

Key words:  sagebrush species  non-rectangle hyperbolae  light response curve,adaption

摘要:

对中国四种蒿属植物(毛莲蒿、蒙古蒿、牡蒿和灰苞蒿)的光合响应曲线进行了研究。结果表明:牡蒿具有高光饱点(411.0 μmol·m^-2·s^-1)和最大光合速率(18.627 μmol·m^-2·s^-1),以及较低的光补偿点(17.867 μmol·m^-2·s^-1),对高光的适应能力最强; 灰苞蒿的暗呼吸速率(0.353 μmol·m^-2·s^-1)和表观量子效率(0.038)最低,说明该种对弱光的适应能力较差,且在弱光条件下只能维持较低的生长速率; 灰苞蒿水分利用效率随光强的变化趋势与其他三种蒿属植物一致,但总体上维持在一个较高的水平,可能与其对干旱生境的适应有关。光合响应曲线各个拟合指标在种间呈现出了较大的变异,其中光补偿点(L_cp μmol·m^-2·s^-1)和暗呼吸速率(R_day μmol·m^-2·s^-1)差异达到了显著水平。说明植物功能性状与植物对环境长期适应密切相关,并且这种适应性是稳定可遗传的。

Abstract:

The light curves of Artemisia vestita,A. mongolica,A. japonica and A. roxburghiana were measured,and parameters of photosynthesis were calculated by non-rectangle hyperbolae function. Our results showed that A. japonica had higher light saturation point(411.0 μmol·m^-2·s^-1),higher maximum net photosynthetic rate(18.627 μmol·m^-2·s^-1)and lower light compensation point(17.867 μmol·m^-2·s^-1)than other species,revealing a higher ability to adapt highlight conditions for A. japonica. A. roxburghiana had the lowest values of dark respiration(0.353 μmol·m^-2·s^-1)and apparent quantum yield(0.038),indicating this species only maintained a low growth rate under low light conditions. Although the four species had similar trends in water use efficiency in response to increasing light densities,A. roxburghiana exhibited higher levels of WUE than those of other species,which might be reflected an adaptation to drought conditions. Furthermore,the parameters derived from light response curves exhibited a higher variation among species,especially for L_cp and R_day. Overall,those results confirmed the hypothesis that the expression of plant functional traits was closely related to the long-term adaptation of plants to environment and survival strategy.