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

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(411.0μmol·m-2·s-1)和最大光合速率(18.627μmol·m-2·s-1),以及较低的光补偿点(17.867μmol·m-2·s-1),对高光的适应能力最强;灰苞蒿的暗呼吸速率(0.353μmol·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 cpμmol·m-2·s-1)和暗呼吸速率(R dayμmol·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。

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（411.0μmol·m-2·s-1）,higher maximum net photosynthetic rate（18.627μmol·m-2·s-1）and lower light compensation point（17.867μmol·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 （0.353μmol·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 in-creasing 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 exhibi-ted a higher variation among species,especially for Lcp and Rday .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.