乌兰布和沙漠油蒿叶片PSⅡ叶绿素荧光动力学参数及其光响应曲线动态

Dynamic changes of leaf parameters of PSⅡ fluorescence kinetics and fast photosynthetic response curves in Artemisia ordosica

本研究以内蒙古磴口原生油蒿(Artemisia ordosica)为对象,分析了7–9月生长期油蒿比叶面积、叶片氮含量、叶片PSⅡ荧光动力学参数及快速光响应曲线光合生理指标动态变化。结果表明,油蒿比叶面积(specific leaf area,SLA)在8月达到最大值,9月显著降低(P <0.05),叶氮含量(N_(mass))呈现相反的变化趋势;油蒿的初始荧光(F_o)、最大荧光(F_m)以及最大光化学效率(F_v/F_m)在保持相对稳定;光下最小荧光产量(F_o′)和最大荧光产量(F_m′)以8月最高,9月显著下降(P <0.05);光合电子传递量子效率(ΦPSⅡ)及光化学猝灭(qP)随着光强的增加而降低,非光化学猝灭(NPQ)和光合电子传递速率(ETR)随光强的增加而增加;同光强作用下,油蒿叶片ETR和NPQ以9月最高,而8月最低。表明油蒿叶片具有相对较高的光能捕获和光抑制自我保护能力。

To explore the mechanisms of adaptive physiological and ecological responses of Artemisia ordosica to desert environments, the dynamic changes of the specific leaf area (SLA), leaf nitrogen content (Nmass), photosynthetic physiological parameters of PSⅡ fluorescence kinetics, and fast photosynthetic response curves of A. ordosica during growth periods were analyzed. The results showed that SLA was the highest in August, but decreased significantly in September (P < 0.05), and Nmass showed the opposite tendency. The initial fluorescence (Fo), maximum fluorescence (Fm), and maximum photochemistry efficiency (Fv/Fm) of A. ordosica maintained relatively stable values throughout the growth periods. The minimum fluorescence yield (Fo′) and maximum fluorescence yield (Fm′) under stabilization light varied significantly in different growth stages, with the highest values recorded in August and the lowest in September (P < 0.05). The photosynthetic electron transfer quantum efficiency (ΦPSⅡ) and photochemistry quenching (qP) decreased with the increase of light intensity, while the non-photochemical quenching (NPQ) and photosynthetic electron transfer rate (ETR) showed the opposite trend. The ETR and NPQ of the A. ordosica leaves were the highest in September and the lowest in August under the same light intensity. The results indicated that the leaves of A. ordosica had a high ability to regulate light capture and resist photoinhibition as an adaptation to light environmental changes.