环境因子对东海原甲藻生长及脲酶活性的影响  

Effects of environmental factors on the growth and urease activity of the harmful dinoflagellate Prorocentrum donghaiense

作　　者：蔡雨[1] 刘静雅[1] 秦俊莲[1] 孙树刚[1] 段舜山[1] 徐宁[1] 

机构地区：[1]暨南大学生态学系水生生物研究所,广州510632

出　　处：《生态学报》2016年第6期1711-1718,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(U1133003;40776078)

摘　　要：以我国东南沿海大规模赤潮原因种东海原甲藻为实验材料,研究了环境因子对其生长及脲酶活性的调控作用。结果表明,东海原甲藻的适宜生长温度为20—25℃,而25℃下脲酶活性最高。在光强2μmol m-2s-1条件下细胞密度显著下降(P<0.05),但仍能维持较高的脲酶活性(9.405 fmol h-1个-1)。在盐度20—40范围内,东海原甲藻能够维持快速生长和较高的脲酶活性。氮源组成对东海原甲藻生长无显著影响,但对脲酶活性影响较大。具体而言,东海原甲藻脲酶活性与尿素浓度呈显著正相关关系,而无机氮源NH+4和NO-3对其脲酶活性具有显著的抑制作用,在氮缺乏条件下脲酶活性明显增强。东海原甲藻脲酶活性对环境温度、光照、盐度和营养的响应特征可能是在长期进化中形成的生态适应策略,使其在无机氮源不足时得以转而利用有机氮源,从而在资源竞争中占据有利地位。In the last few decades,the geographic distribution and frequency of harmful algal blooms（ HABs） have been increasing worldwide,and have resulted in severe economic losses and ecological disaster. There has been a scientific consensus that there is a positive relationship between occurrences of HABs and increased eutrophication due to human activities in coastal waters. Studies demonstrated that urea has seen wide use in agriculture as a major nitrogen fertilizer in recent years,and consequently,concentrations of urea in aquatic environments have increased dramatically,becoming an important component of dissolved organic nitrogen（ DON） in coastal waters. Other studies demonstrated the presence of a positive correlation between the increased input of urea into coastal waters and HABs frequencies. However,the ecological role of urea in triggering HABs,and the mechanism by which it does so（ in a species-specific and physiological context in particular）,are still unclear. The armored dinoflagellate Prorocentrum donghaiense is a representative HABs-causing alga found in the southeastern coastal waters of China,and has caused serious damage to fisheries and aquaculture facilities,and threatened coastal aquatic ecosystems. This species has shown a wide range of tolerance to light,temperature,and salinity,and is capable of utilizing both inorganic（ NO-3and NH＋4） and organic（e. g. urea and amino acids） forms of nitrogen（N）. Based on our prior study,in which we demonstrated that P. donghaiense exhibits a higher growth rate when grown in media containing urea as the sole N source,compared to those grown with NO-3as the N source,we investigated the effects of environmental factors（ temperature,light intensity,and salinity） on the growth of P. donghaiense,and further exploredthe potential regulating effects of these factors and different forms of N on the activity of urease,a key enzyme involved in the metabolism of urea. The optimal temperatures for P. donghaiense growth were between 20 and 25°

关 键 词：东海原甲藻 脲酶活性 生长 尿素 环境因子 

分 类 号：Q945[生物学—植物学]