中文摘要：

为探讨太阳紫外辐射（UVR,280～400 nm）和CO2浓度变化对大型海藻的复合效应,选择了常见的经济海藻龙须菜（Gracilarialemaneiformis）为实验材料,研究了UVR（阳光紫外辐射）和CO2对其生长、光合作用、色素以及紫外吸收物质含量变化的复合作用。实验设置两个CO2梯度（380×10-6和800×10-6）和三种太阳辐射处理（PAB处理——全波长辐射处理,PA辐射处理——滤掉紫外线B和P处理——滤掉全部紫外线）。结果表明,CO2加富（800×10-6）显著地促进了龙须菜的生长,而UVR则产生抑制作用,但两者之间复合作用不显著。UVR促进了藻体的紫外吸收物质的合成,而且在高浓度CO2下经PAB辐射处理的含量要显著高于正常CO2浓度水平下的,这表明高浓度CO2促进了紫外吸收物质的合成。在光合作用受限制的低PAR条件下,紫外线A（UV-A）促进其光合作用,但高浓度CO2却抑制了藻体的光合作用速率。在正常浓度CO2水平下生长的藻体,UVR显著降低其光合作用能力,但是在高浓度CO2下生长的藻体,UVR这种负面效应不显著。UVR显著降低藻红蛋白的含量,高浓度CO2在P和PA辐射处理下也显著降低藻红蛋白的含量,但在PAB辐射处理下却呈现相反的结果。高浓度CO2下生长的藻体通过增加体内紫外吸收物质的含量来维持较高浓度的藻红蛋白含量,增强了其抵御UVR的能力。

英文摘要：

The economic red macroalga Gracilaria lemaneiformis was selected to study the co-effects of CO2 and solar UVR（280～400 nm） on its growth,photosynthesis,pigments and UVAC contents.Two CO2 concentration levels（380×10-6 and 800×10-6） and three solar radiation treatments（PAB treatment,the thalli receiving full solar radiation;PA treatment,UV-B was cut off,P treatment,all UV radiation were cut off）.Results show that the relative growth rate of the thalli increases when the thalli is cultured in high concentration CO2 condition（800×10-6） and it decreases in the presence of UVR,but the co-effects of CO2 and solar UVR are not significant.UVR significantly increase the content of UV-absorbing compounds of Gracilaria lemaneiformis,and further increase of the content of UVACs in PAB treatment is found under CO2 enriched condition.The positive effects on photosynthesis of Gracilaria lemaneiformis is found in the presence of UV-A when photosynthesis is limited by low PAR.the negative effects are found when the thalli is cultured under CO2 enriched condition.UVR significantly decreases the photosynthetic rate of the Gracilaria lemaneiformis when the thalli is cultured under normal CO2 level condition,while no effects of UVR is found when the thalli is cultured under CO2-enriched condition.UVR significantly decreases the content of phycoerythrin,and high concentration CO2 also decreases the content of phycoerythrin under P and PA treatment,but the opposite result is found in PAB treatment.In conclusion,it is shown that Gracilaria lemaneiformis grown under CO2-enriched condition can eliminate the deleterious influence of UVR on photosynthesis by increasing UVAC contents and keeping the high content of phycoerythrin in thalli.