盐度及钒酸钠胁迫对红毛菜光合生理的影响

Effects of Salinity and Na3VO4 Stress on Photosynthetic Physiology of Bangia

中文关键词: 红毛菜  盐度  钒酸钠  PSⅡ原初光能转化效率  表观光合速率  呼吸耗氧速率

英文关键词: Bangia  Salinity  Sodium orthovanadate  Conversion efficiency of primary light energy of PS Ⅱ  Net photosynthetic rate  Respiratory oxygen consumption rate

中文摘要:

      利用叶绿素荧光技术和液相氧电极技术，研究了盐度与钒酸钠胁迫对红毛菜(Bangia fuscopurpurea，海水种)和暗紫红毛菜(Bangia atropurpurea，淡水种)光合作用的影响。结果显示，红毛菜和暗紫红毛菜分别在低盐、高盐下胁迫1 h，PSⅡ原初光能转化效率(Fv/Fm)均快速下降，且下降幅度与胁迫程度正相关；第3天开始，盐度0和8对红毛菜Fv/Fm具有明显抑制效应，盐度16和24组与对照组相当；暗紫红毛菜各高盐胁迫组的Fv/Fm从第1天开始显著低于对照组，但到后期(6~7 d)与对照组间无显著差异。盐度胁迫对2种红毛菜的表观光合速率(Pn)影响显著，尤其到后期(3 d后)，多数实验组Pn均显著降低。红毛菜的呼吸耗氧速率(Rd)在胁迫早期的变化与Fv/Fm一致，呈先下降后快速恢复到对照组水平；暗紫红毛菜随胁迫时间的延长，胁迫组Rd呈上升趋势，显著高于对照组。高浓度(200~500 μmol/L)钒酸钠胁迫3 d后可显著抑制红毛菜Fv/Fm，暗紫红毛菜的Fv/Fm在钒酸钠胁迫1 d后呈下降趋势，且下降幅度与钒酸纳胁迫程度正相关。整体上，随着钒酸钠浓度增加，低盐、高盐胁迫分别加重红毛菜和暗紫红毛菜的Fv/Fm和Pn的抑制效应。而Rd随胁迫程度的增加而升高，在暗紫红毛菜中尤为明显。研究表明，红毛菜和暗紫红毛菜对盐度胁迫可作出快速响应，其呼吸作用的增强及对质膜-H+-ATPase的调控，可能在应对盐度胁迫时发挥重要作用，而较长时间盐度胁迫对2种红毛菜的光合作用均产生不可逆影响。

英文摘要:

      The effect of salinity and Na3VO4 on photosynthesis of Bangia fuscopurpurea and Bangia atropurpurea was investigated, respectively, to investigate the photosynthetic physiology of Bangia, using chorophyll Ⅱ fluorescence and photosynthetic oxygen evolution measurements. The main results were as follows: The conversion efficiency of primary light energy of PSⅡ (Fv/Fm) of B. fuscopurpurea declined rapidly in salinity conditions lower than natural seawater while that of B. atropurpurea declined in salinity higher than freshwater, and the decrease was positively related to the level of stress. The Fv/Fm of B. fuscopurpurea was significantly inhibited under salinity 0 and 8 after 3 days of hyposaline treatment. No significant difference was seen among the different hyposalinity-stressed groups of B. fuscopurpurea. The Fv/Fm of B. atropurpurea under hypersaline stress was significantly lower than that of the control from the first day, and recovered to control levels after 6 or 7 days of hypersaline treatment. Saline stress had significant effects on net photosynthetic rate (Pn) in both Bangia species. Respiratory oxygen consumption rate (Rd) decreased at the early stage and then rapidly recovered to the level of the control on the first day. After 1 day, Rd of the hyposalinity-stressed B. fuscopurpurea groups was significantly lower than the control. As the hypersalinity continued, Rd of the stressed B. atropurpurea increased and became significantly higher than the control. After 3 days, the Fv/Fm of B. fuscopurpurea decreased significantly under treatment with 200~500 μmol/L Na3VO4. The decrease of Fv/Fm in B. atropurpurea with Na3VO4 treatment was positively correlated with Na3VO4 concentration. In general, with an increase in Na3VO4 concentration, the salinity stress had significant inhibitory effect on the Fv/Fm and Pn of Bangia. Rd of both B. fuscopurpurea and B. atropurpurea increased with stress, an effect that was more obvious in B. atropurpurea. The present results reveal that both marine and freshwater Bangia respond quickly to saline stress. The enhancement of Rd and regulation of plasma membrane-H+-ATPase may play an important role in response to saline stress. Long-term saline stress had irreversible harmful effects on photosynthesis in Bangia.