pH和氮磷比对微小原甲藻和青岛大扁藻生长竞争的影响  

Effect of pH level and N/P ratio on growth and competition of the microalgae Tetraselmis helgolandica and Prorocentrum minimum

作　　者：葛红星[1,2] 陈钊[1] 李健[2,3] 冯艳艳[2] 刘思涛 赵法箴[2] 

机构地区：[1]中国海洋大学水产学院,山东青岛266003 [2]中国水产科学研究院黄海水产研究所农业部海洋渔业可持续发展重点实验室,山东青岛266071 [3]青岛海洋科学与技术国家实验室海洋渔业科学与食物产出过程功能实验室,山东青岛266071 [4]潍坊新大地水产养殖有限公司,山东潍坊261108

出　　处：《中国水产科学》2017年第3期587-595,共9页Journal of Fishery Sciences of China

基　　金：国家虾产业技术体系-北方养殖岗位(CARS-47);山东省泰山产业领军人才工程项目(LNJY2015002);青岛海洋科学与技术国家实验室鳌山科技创新计划项目(2015ASKJ02)

摘　　要：为探讨pH和氮磷比对青岛大扁藻(Tetraselmis helgolandica)和微小原甲藻(Prorocentrum minimum)生长竞争的影响,本研究首先根据对虾养殖水体pH值的范围设置了7.5,8.0,8.5和9.0共4个pH梯度,获得了青岛大扁藻抑制微小原甲藻的最佳pH;在该pH条件下,设置了氮磷比分别为3:2(高富磷组),6:1(富磷组),24:1(对照组)和96:1(富氮组)等4个梯度,其中,单种培养体系中只接种青岛大扁藻或者微小原甲藻,混合培养体系中同时按照1:1的比例接种青岛大扁藻和微小原甲藻。结果表明,混合培养体系中,青岛大扁藻在pH 8.5和pH 9.0时,出现拐点时间最晚,均为7 d;而微小原甲藻在pH 8.5和pH 9.0时,出现拐点时间最早,均为3 d。pH 8.5时青岛大扁藻对微小原甲藻的竞争抑制参数最大,青岛大扁藻抑制微小原甲藻的最佳pH为8.5。单种培养体系中,微小原甲藻拐点出现的时间在高富磷组、对照组和富氮组中均晚于青岛大扁藻;混合培养体系中,对照组中微小原甲藻和青岛大扁藻拐点出现时间分别为4 d和3 d,而其他处理组2种微藻拐点出现的时间分别相同。氮磷比影响混合培养中2种微藻的竞争抑制参数,其中,96:1(富氮组)中拐点之后青岛大扁藻对微小原甲藻的竞争抑制参数(α)的平均值为9.2063,微小原甲藻对青岛大扁藻的竞争抑制参数(β)为3.4886。以上研究表明,对虾养殖水体中,青岛大扁藻抑制微小原甲藻的最佳条件是:pH为8.5,氮磷比为96:1。Tetraselmis helgolandica, with several varieties, is one of numerous species of unicellular flee-swimming marine green algae that are widely used for intensive rearing of a variety of marine animal larvae. Prorocentrum minimum is a dinoflagellate capable of producing powerful biotoxins and it is commonly found in shrimp ponds. Chief physical and chemical concerns of the commercial growing environment of microalgae are pH and the nitrogen-phosphorus （N/P） ratio. To identify the optimum growth conditions of Tetraselmis helgo- landica to inhibit the growth of Prorocentrum minimum in shrimp ponds, we tested for interspecies competition at various nutrient concentrations after determining the optimum pH for each species. Prior to the start of each test, in vitro cultures were maintained for an adaption period of approximately 5 generations. Thereafter, the experiments were conducted in batch cultures and continued up to 10 days, and the microorganisms were grown until either late exponential phase or early stationary phase. The pH levels and N/P ratios chosen took into account the common environmental conditions found in shrimp ponds. With this in mind, a culture experiment was first carried out using four different pH levels （7.5, 8.0, 8.5 and 9.0） and a constant N/P ratio of 24, so as to determine the optimum growth rate for Tetraselmis helgolandica. After deciding the best pH conditions, the N/P ratio was selected considering the concentrations of DIN and DIP found in shrimp ponds. The next test thus used four different N/P ratios： 3 ： 2, 6 ： 1, 24 . 1 and 96 ： 1. The results showed that the maximum carrying capacity （K） of both Tetraselmis helgolandica and Prorocentrum minimum was lower than that in the environments of individual cultivation. This finding indicated that the inhibition parameter of interspecies competition between these two algae could be significantly influenced by pH conditions. The maximum rate of competition inhibition of Tetraselmis helgolandica against Prorocentrum minimum

关 键 词：PH 氮磷比 青岛大扁藻 微小原甲藻 种间竞争 

分 类 号：S963[农业科学—水产养殖]