光强和二氧化碳浓度变化对浒苔幼苗生长及生理的影响

The effects of light and increased CO_2 on the growth and physiological performances in marine green algae Ulva proliferaseedling

大气CO2浓度升高引起的海洋酸化如何在光变环境下影响大型海藻固碳量的问题,关系到未来海洋初级生产力的变化趋势。为研究大型海藻对CO2浓度升高和光强变化的响应,本文选取浒苔(Ulva prolifera)幼苗为实验材料,探讨其在不同光强下[80、260μmol/(m2·s)]和两种CO2浓度(正常CO2浓度:400μL/L和高CO2浓度:1 000μL/L)下的生理变化。研究发现,在正常CO2浓度、高光条件下,浒苔幼苗的生长最快,超氧化物特化酶(SOD)活性最高,而过氧化氢酶(CAT)活性在低光、高CO2处理下有最大值。光合色素含量和光系统Ⅱ的光化学效率在不同处理间没有显著性差异,但叶绿素a与类胡萝卜素的比值在低光正常CO2处理下有最大值。同时,高光高CO2处理下,浒苔幼苗的可溶性蛋白含量最低。

Ocean acidification due to increasing anthropogenic CO2 is expected to influence marine primary productiv-ity.In order to investigate the interactive effects of increased light and CO2 changes on macroalgae,we grewUlva prolifera seedling under the normal CO2 level （400 μL/L）and elevated CO2 level （1 000 μL/L）conditions,the light levels set as 80 and 260 μmol/（m2 ＆#183;s）,and measured its physiological performance.Research finding that the specific growth rate and activity of SOD was highest under high light and normal CO2 level .However,the activity of CAT showed the highest value under the high CO2 and low light conditions.Under the different treatments, there was no significant effect on the chlorophyll a and maximal photochemical yield of PSⅡ （Fv/Fm ）,while the largest ratios of chlorophylla to carotenoid occurred at nomal CO2 and low light conditions.Meanwhile,the content of soluble protein was decreased by high light and high CO2 .