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We report the effect of UV-B irradiation (9.6 kJ m?2 day?1) on interspecific competition between two species of macroalgae, Ulva pertusa (U) and Grateloupia filicina (G), in co-culture. Growth of U. pertusa and G. filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate (μ) declined as a result. Interspecific competition between U. pertusa and G. filicina was closely related to the initial weights when co-cultured. When initial ratios of U. pertusa (U) to G. filicina (G) were U:G=1.2:1 and 1:1, U. pertusa was the dominant algae. When the initial U:G ratio was 1:1.2, G. filicina was competitively dominant in the earlier stage, but U. pertusa grew faster, superseding G. filicina in the later stage. At initial ration U:G = 1:1.4, G. filicina was predominant. Under UV-B irradiation, the competitive ability of G. filicina was weakened and the interspecific competitive balance favored U. pertusa, which suggests that G. filicina was more sensitive to UV-B irradiation. We also probed the potential allelopathic effects between the two species, which led to mutual growth inhibition. 相似文献
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Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupiafilicina （Rhodophyta） 总被引：1，自引：0，他引：1
Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance.We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase(SOD),peroxidase(POX),catalase(CAT),and ascorbate peroxidase(APX) of red algae Grateloupia filicina(Lamour.) C.Agardh.The activities of SOD,CAT,and APX changed in response to UV-B in a time- and dose-dependent manner.POX activity increased significantly under all three UV-B treatments.The enzymatic assay showed three distinct bands of SODⅠ(Mn-SOD),SODⅡ(Fe-SOD),and SODⅢ(CuZn-SOD) under a low(Luv) and medium(Muv) dose of UV-B irradiation,while SODⅠ and SODⅢ activities decreased significantly when exposed to a high dose of UV-B irradiation(Huv).The activity of POX isoenzymes increased significantly after exposure to UV-B,which is consistent with the total activity.In addition,a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments.Some bands of APX isoenzyme were also clearly influenced by UV-B irradiation.Correspondingly,the daily growth rate declined under all the three exposure doses,and was especially significant under Muv and Huv treatments.These data suggest that,although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage,G.filicina has incomplete tolerance to higher UV-B irradiation stress. 相似文献
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紫外辐射对孔石莼抗氧化酶活性及其同工酶表达的影响 总被引：1，自引：0，他引：1
潮间带海藻不可避免地要遭受UV-B的胁迫。本研究以孔石莼(Ulva pertusa)为试材,研究了UV-B胁迫对其抗氧化酶体系中SOD、CAT、POX、APX、GR、GPX活性及前4种酶的同工酶表达的影响。结果显示:SOD、CAT、POX酶活性应激反应较为迅速;APX活性始终保持较稳定水平;GR、GPX酶应激表达启动稍晚,酶活高峰在处理中期6d时出现。SOD同工酶谱有4条酶带,在UV-B3种剂量处理下,SODⅠ及SODⅡ同工酶活性有所增加;POXⅡ同工酶活性呈小幅增加;在UV-B诱导下,CAT产生了2条新的同工酶谱带CATⅠ及CATⅡ;APX同工酶仅有1条谱带,在UV-B处理下与对照差异不大。抗氧化成分As A及GSH含量在处理前中期与对照相近。孔石莼的特定增长率(SGR)在1.6 kJ/(m~2·d)、4.8 kJ/(m~2·d)和9.6kJ/(m~2·d)3种剂量UV-B辐射处理下均呈下降趋势,且在后两种剂量处理下降低尤为显著,而相应的H_2O_2及TBARS含量呈不同程度增加。上述结果表明:孔石莼对UV-B辐射具有一定程度的耐受性,可以通过提高酶促过氧化体系活性来应答UV-B导致的氧化胁迫,并且酶活性变化体现出剂量和时间效应。 相似文献
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We report the effect of UV-B irradiation(9.6 kJ m-2day-1)on interspecific competition between two species of macroalgae,Ulva pertusa(U)and Grateloupia filicina(G),in co-culture.Growth of U.pertusa and G.filicina was inhibited by UV-B irradiation in mono-culture and specific growth rate (μ)declined as a result.Interspecific competition between U.pertusa and G.filicina was closely related to the initial weights when co-cultured.When initial ratios of U.pertusa(U)to G.filicina(G)were U:G=1.2:1 and 1:1,U.pertusa was the dominant algae.When the initial U:G ratio was 1:1.2,G.filicina was competitively dominant in the earlier stage,but U.pertusa grew faster,superseding G.filicina in the later stage.At initial ration U:G=1:1.4,G.filicina was predominant.Under UV-B irradiation,the competitive ability of G.filicina was weakened and the interspecific competitive balance favored U.pertusa,which suggests that G.filicina was more sensitive to UV-B irradiation.We also probed the potential allelopathic effects between the two species,which led to mutual growth inhibition. 相似文献
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