Over the past few years, harmful algal blooms （HABs）, such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can a...Over the past few years, harmful algal blooms （HABs）, such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can alter the structure and succession of aquatic ecosystems. We investigated the influence of four environmental factors （temperature, salinity, light, and pH） on the allelopathic effects of the macroalgae Corallina pilulifera on red-tide forming Heterosigma akashiwo under laboratory conditions. Each of the factors had four levels： temperature （15, 20, 25, and 30℃）, salinity （10, 20, 30, and 40）, light （20, 100, 200 and 400 gmol/（m2.s））, and pH （5.5, 7, 8.5, and 10. Two-factor experiments were designed for each two environmental factors, with six combination treatments （temperature-salinity, temperature-light, temperature-pH, salinity-light, salinity-pH, and light-pH）. Results showed that the allelopathic effect was significantly influenced by temperature, salinity, light, and pH. As single factors, the low temperature （15 ℃）, low salinity （10）, high-intensity light （400umol/（m2.s））, and high pH （10） treatments substantially enhanced the allelopathic effect. The strongest allelopathic effect of C. pilulifera on H. akashiwo was observed under the following treatments： 15℃ and salinity of 40, 25℃ and pH 10, 25℃ with medium- to high-intensity light at 200-400 umol/（m2.s）, 400umol/（m2.s） and salinity of 10, 400 gmol/（m2·s） and pH 10, and pH 10 with a salinity of 40.展开更多
Intertidal macroalgae can cope with the dual effects of UV-B irradiation and allelopathy.To study the impacts of the two stressors,we co-cultured Corallina pilulifera with Sargassum thunbergii in 1:1 and 1:10 ratios u...Intertidal macroalgae can cope with the dual effects of UV-B irradiation and allelopathy.To study the impacts of the two stressors,we co-cultured Corallina pilulifera with Sargassum thunbergii in 1:1 and 1:10 ratios under different doses of UV-B radiation.The response of the antioxidant defense system,focusing on activities of superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POX)and glutathione reductase(GR),was monitored.In addition,isoenzyme patterns were analyzed using nondenaturing poly acry lamide gel electrophoresis.The results show that the activities of SOD,APX,and GR were all significantly affected by both UV-B radiation and allelopathy,and the effect of their interaction was significant.However,POX activity was only influenced by UV-B radiation.The enzymatic assay revealed four distinct bands of SOD.The SODⅢband weakened significantly when the co-cultures were exposed to extremely high dosage of UV-B irradiation under both co-culturing ratios of 1:1 and 1:10.When the coculturing ratio was 1:10,both POXⅡand APXⅡenzy me activities increased with different UV-B doses.GR activity was at its greatest when the co-culture ratio was 1:10 and exposure was to the higher UV-B doses.The activities of GRⅢand GRⅣwere elevated under all UV treatments whereas the activities of GRI and GRII were reduced under the lower UV-B treatments but were elevated under the higher UV-B treatments.However,lipid peroxidation,as indicated by the thiobarbituric acid-reacting substance(TBARS)assay,increased significantly under the dual stressors.Our data sugge st that allelopathy and UV-B radiation stre ss can each affect the antioxidant enzyme activities of C.pilulifera.Critically,the adverse effects of UV-B on C.pilulifera were intensified by the compounding effects of allelopathy.展开更多
In the present study, we evaluated the allelopathic effects of three macroalgae, namely Ulva pertusa Kjellml, Corallina pilufifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze, on the growth of the microal...In the present study, we evaluated the allelopathic effects of three macroalgae, namely Ulva pertusa Kjellml, Corallina pilufifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze, on the growth of the microalga Skeletonema costaturn （Grev.） Creve using culture systems in which the algae coexisted. The effects of the macroalgal culture medium filtrate on S. costatum were also investigated. Moreover, isolated co-culture systems were built to confirm the existence of allelochemicals and preclude growth inhibition by direct contact. The coexistence assay data demonstrated that the growth of S. costaturn was strongly inhibited when fresh tissues, dry powder and aqueous extracts were used; the allelochemicals were lethal to S. costatum at relatively higher concentrations. The effects of the macroalgal culture medium filtrate on the microalga showed both species specificity and complexity. The inhibitory effect of fresh macroalgal tissue and culture medium filtrate on the microalga was due to the alleochemicals released by the macroalgae. The results of the present study show that the allelopathic effects of macroalgae on the microalga are complex. The present study could shed light onto the basis of the interaction between macro- and microalgae.展开更多
基金Supported by the National Natural Science Foundation of China(No.31200400)
文摘Over the past few years, harmful algal blooms （HABs）, such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can alter the structure and succession of aquatic ecosystems. We investigated the influence of four environmental factors （temperature, salinity, light, and pH） on the allelopathic effects of the macroalgae Corallina pilulifera on red-tide forming Heterosigma akashiwo under laboratory conditions. Each of the factors had four levels： temperature （15, 20, 25, and 30℃）, salinity （10, 20, 30, and 40）, light （20, 100, 200 and 400 gmol/（m2.s））, and pH （5.5, 7, 8.5, and 10. Two-factor experiments were designed for each two environmental factors, with six combination treatments （temperature-salinity, temperature-light, temperature-pH, salinity-light, salinity-pH, and light-pH）. Results showed that the allelopathic effect was significantly influenced by temperature, salinity, light, and pH. As single factors, the low temperature （15 ℃）, low salinity （10）, high-intensity light （400umol/（m2.s））, and high pH （10） treatments substantially enhanced the allelopathic effect. The strongest allelopathic effect of C. pilulifera on H. akashiwo was observed under the following treatments： 15℃ and salinity of 40, 25℃ and pH 10, 25℃ with medium- to high-intensity light at 200-400 umol/（m2.s）, 400umol/（m2.s） and salinity of 10, 400 gmol/（m2·s） and pH 10, and pH 10 with a salinity of 40.
基金Supported by the National Natural Science Foundation of China(Nos.31971546,31300326)。
文摘Intertidal macroalgae can cope with the dual effects of UV-B irradiation and allelopathy.To study the impacts of the two stressors,we co-cultured Corallina pilulifera with Sargassum thunbergii in 1:1 and 1:10 ratios under different doses of UV-B radiation.The response of the antioxidant defense system,focusing on activities of superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POX)and glutathione reductase(GR),was monitored.In addition,isoenzyme patterns were analyzed using nondenaturing poly acry lamide gel electrophoresis.The results show that the activities of SOD,APX,and GR were all significantly affected by both UV-B radiation and allelopathy,and the effect of their interaction was significant.However,POX activity was only influenced by UV-B radiation.The enzymatic assay revealed four distinct bands of SOD.The SODⅢband weakened significantly when the co-cultures were exposed to extremely high dosage of UV-B irradiation under both co-culturing ratios of 1:1 and 1:10.When the coculturing ratio was 1:10,both POXⅡand APXⅡenzy me activities increased with different UV-B doses.GR activity was at its greatest when the co-culture ratio was 1:10 and exposure was to the higher UV-B doses.The activities of GRⅢand GRⅣwere elevated under all UV treatments whereas the activities of GRI and GRII were reduced under the lower UV-B treatments but were elevated under the higher UV-B treatments.However,lipid peroxidation,as indicated by the thiobarbituric acid-reacting substance(TBARS)assay,increased significantly under the dual stressors.Our data sugge st that allelopathy and UV-B radiation stre ss can each affect the antioxidant enzyme activities of C.pilulifera.Critically,the adverse effects of UV-B on C.pilulifera were intensified by the compounding effects of allelopathy.
基金Supported by the National Natural Science Foundation of China （30270258 and 40506028） and Encouraging Foundation for 0utstanding Youth Scien- tists of Shangdong Province （03BS 120）.The authors thank Professor Guangxi Xing for his useful comments on the manuscript and for improving an earlier vision of this paper.
文摘In the present study, we evaluated the allelopathic effects of three macroalgae, namely Ulva pertusa Kjellml, Corallina pilufifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze, on the growth of the microalga Skeletonema costaturn （Grev.） Creve using culture systems in which the algae coexisted. The effects of the macroalgal culture medium filtrate on S. costatum were also investigated. Moreover, isolated co-culture systems were built to confirm the existence of allelochemicals and preclude growth inhibition by direct contact. The coexistence assay data demonstrated that the growth of S. costaturn was strongly inhibited when fresh tissues, dry powder and aqueous extracts were used; the allelochemicals were lethal to S. costatum at relatively higher concentrations. The effects of the macroalgal culture medium filtrate on the microalga showed both species specificity and complexity. The inhibitory effect of fresh macroalgal tissue and culture medium filtrate on the microalga was due to the alleochemicals released by the macroalgae. The results of the present study show that the allelopathic effects of macroalgae on the microalga are complex. The present study could shed light onto the basis of the interaction between macro- and microalgae.
