【作者】 邓平；

【导师】 吴振斌；

【作者基本信息】 中国科学院研究生院（水生生物研究所） ， 环境科学， 2007， 博士

【摘要】 水生植物的化感作用对淡水生态系统中群落的组成和富营养化湖泊的生态修复具有非常重要的意义。本文选择三种常见沉水植物小茨藻、马来眼子菜和菹草,研究在共培养系统中对斜生栅藻、汉氏菱形藻和铜绿微囊藻的化感效应。同时研究三种植物的种植水对斜生栅藻、汉氏菱形藻和铜绿微囊藻生长的影响,并探讨在富营养化湖泊恢复过程中菹草是否存在化感作用。主要研究结果如下:1.在共培养实验中小茨藻明显抑制了两种不同起始密度斜生栅藻的生长(OD650、细胞数和叶绿素a)。仅在共培养结束当天斜生栅藻的光合作用和呼吸作用受到了3.75 g/L的小茨藻的影响。共培养结束时对斜生栅藻的一些生理指标和细胞形态进行了测试。对于起始低密度的斜生栅藻, 2.5 g/L的小茨藻明显促进了斜生栅藻丙二醛(MDA)含量的增加,刺激了三种抗氧化酶(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD))、硝酸还原酶(NR)和碱性磷酸酶(APA)的活性;除影响抗氧化酶系统和APA的活性外,3.75 g/L的小茨藻还明显促进了斜生栅藻可溶性蛋白含量的增加,但凝胶电泳的结果显示其39.8 kDa的蛋白条带消失。对于起始高密度的斜生栅藻,两种生物量的小茨藻都明显促进了斜生栅藻可溶性蛋白含量的增加,影响了藻的抗氧化酶系统,抑制了与氮代谢相关的NR活性,使其39.8 kDa的蛋白条带消失。两种不同起始密度的斜生栅藻都是以四细胞形态为主。共培养结束时小茨藻叶绿素a含量未受到明显影响。小茨藻对斜生栅藻的生长和生理过程存在明显的化感效应。一次添加小茨藻种植水对斜生栅藻的生长没有表现出明显的抑制作用,而且缺氮、缺磷培养过的斜生栅藻并不比正常培养的更敏感。2.在共培养实验中马来眼子菜明显抑制了两种不同起始密度斜生栅藻的生长,并对光合作用也产生了明显的抑制作用。共培养结束当天对斜生栅藻的一些生理指标和细胞形态进行了测试。与两种生物量的马来眼子菜共培养的起始低密度斜生栅藻的三种抗氧化酶(SOD、CAT、POD)和APA的活性都明显增强,可溶性蛋白和MDA含量显著增加,某些蛋白条带消失(3.75 g/L马来眼子菜还促进了斜生栅藻的NR活性)。除不影响起始高密度斜生栅藻的SOD、NR和APA活性外,马来眼子菜对其它生理指标的影响依赖于马来眼子菜的生物量。两种不同起始密度的斜生栅藻都是以四细胞形态为主。抑制作用较强的共培养种植水(起始低密度斜生栅藻)对再接种的斜生栅藻的生长没有产生明显抑制作用。植物与起始低密度斜生栅藻共培养结束时叶绿素a含量增加。马来眼子菜对斜生栅藻的生长和生理过程存在明显的化感效应;起始低密度的斜生栅藻对马来眼子菜的叶绿素a含量有一定的促进作用。对马来眼子菜进行曝气处理或实验前对斜生栅藻进行缺氮、缺磷培养,一次添加的种植水都不能抑制斜生栅藻的生长。3.在共培养实验中菹草对两种不同起始密度斜生栅藻的生长都表现出明显的抑制作用。由于接种藻细胞形态的不同,植物处理中的起始高密度斜生栅藻在培养最初几天形成更多的多细胞形态,到培养结束时差异已不明显。植物对细胞形态也存在一定的影响。共培养结束当天对斜生栅藻的一些生理指标进行了测试。对于起始低密度的斜生栅藻,两处理组中的斜生栅藻可溶性蛋白含量都明显增加,POD和APA活性增强,较高生物量(3.75 g/L)的菹草还使斜生栅藻15.1 kDa的蛋白条带消失。对于起始高密度的斜生栅藻,3.75 g/L的菹草促进了斜生栅藻可溶性蛋白和MDA含量的增加,刺激了藻的CAT和APA活性,并抑制了NR活性;5 g/L的菹草促进了斜生栅藻可溶性蛋白含量的增加,影响了藻的抗氧化酶系统并抑制了APA活性。植物的叶绿素a含量在共培养结束时未受到明显影响。菹草对斜生栅藻的生长和生理过程表现出明显的化感效应。除菹草在不添加营养盐的条件下对无磷培养过的斜生栅藻表现了一定的抑制作用外,其它对植物或对藻的各种培养方式都对斜生栅藻的生长无明显抑制作用。4.在共培养实验中小茨藻对两种不同起始密度汉氏菱形藻的生长都表现出明显的抑制作用,处理组中起始低密度的汉氏菱形藻在实验开始1天后细胞数已非常少。共培养结束当天对起始高密度汉氏菱形藻的一些生理指标进行了测试。2.5 g/L的小茨藻抑制了汉氏菱形藻的CAT活性,使可溶性蛋白含量明显下降,但对蛋白条带没有产生影响;而3.75 g/L小茨藻使汉氏菱形藻的MDA含量降低。共培养结束时小茨藻的叶绿素a含量也明显减少。小茨藻对汉氏菱形藻的生长和生理过程表现出明显的化感效应;汉氏菱形藻对小茨藻的叶绿素a含量也表现出了一定的化感效应。小茨藻种植水未对汉氏菱形藻的生长产生抑制作用。与马来眼子菜共培养的两种不同起始密度的汉氏菱形藻在共培养第4天细胞已几乎全部死亡。在共培养实验中菹草对两种不同起始密度汉氏菱形藻的生长都表现出明显的抑制作用,处理组中起始低密度的汉氏菱形藻在实验开始的第3天细胞数已非常少。共培养结束当天对起始高密度汉氏菱形藻的一些生理指标进行了测试。2.5 g/L的的菹草使汉氏菱形藻可溶性蛋白含量下降并影响到蛋白条带,促进了抗氧化酶(SOD和POD)、NR和APA活性的增强。除不影响可溶性蛋白含量外,3.75 g/L的菹草影响了汉氏菱形藻的蛋白条带,并刺激了其抗氧化酶(CAT和POD)、NR和APA的活性。与汉氏菱形藻共培养的菹草叶绿素a含量在实验结束时未受到明显影响。菹草对汉氏菱形藻的生长和生理过程表现出明显的化感效应。不添加营养盐培养的菹草种植水对磷缺乏和正常培养的汉氏菱形藻都产生了抑制作用。5.小茨藻、马来眼子菜和菹草在共培养实验中都明显抑制了铜绿微囊藻的生长,共培养3-4天后处理组的细胞都表现为死亡。正常营养条件培养的三种植物种植水对铜绿微囊藻的生长均表现出明显的抑制作用。曝气培养较静止培养的马来眼子菜种植水对铜绿微囊藻抑制作用更明显。有根和无根的菹草种植水一次添加或半连续添加对铜绿微囊藻均表现出明显的抑制效果,但在营养盐缺乏条件下培养的菹草种植水对铜绿微囊藻有一定的促进作用。缺磷培养要比正常培养的铜绿微囊藻更敏感,菹草分泌的化感物质是整株植物共同作用的结果。三种植物对铜绿微囊藻的生长都表现出明显的化感效应。6.在菹草生长阶段(2004.12-2005.5),对武汉市月湖浮游植物进行逐月调查。结果表明,在营养盐浓度较高的条件下,浮游植物仍保持较低的生物量和密度,浮游植物生长与温度保持一定的相关性,但与湖水营养盐浓度并不存在相关关系。菹草和其它水生植物(主要是伊乐藻)组成的水生植物群落能使水体的透明度保持较高的状态。在不受营养和光照影响的条件下浮游植物组成中能形成水华的一些常见种类并未随温度升高而出现,可能与水生植物的存在改变了浮游植物群落的结构组成有关。更多还原

【Abstract】 Allelopathy of aquatic macrophytes is of significance on composition of communities in freshwater ecosystems and ecological rehabilitation in eutrophic lakes. Allelopathic effects of three submerged macrophytes Najas minor, Potamogeton malaianus and Potamogeton crispus on Scenedesmus obliquus, Nitzschia hantzschiana and Microcystis aeruginosa were investigated in coexistence experiments and plants filtrates experiments under controlled laboratory conditions. A related field survey was conducted to determine the allelopathic effect of P. crispus on phytoplankton communities in situ. The main results are summarized as following:1. The OD650, cell numbers and Chl a-based growth of S. obliquus at two different initial cell densities was significantly inhibited by N. minor in the coexistence experiments. Only 3.75 g/L N. minor had inhibitory effects on photosynthetic rate (at the lower initial cell density) and respiratory rate (at the higher initial cell density) on the last day of the experiments. Total soluble protein, Lipid peroxidation (MDA), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)), nitrate reductase (NR), alkaline phosphatase (APA), protein electrophoretic pattern and morphology of S. obliquus were determined after the co-culture experiments were terminated. MDA content at the low initial algal cell density was increased, and the activities of SOD, CAT, POD, NR and APA were stimulated in 2.5 g/L N. minor treatment, while antioxidant enzymes systems and APA activity were affected, total soluble protein content was increased, but the 39.8 kDa protein disappeared in 3.75 g/L N. minor treatment. The content of total soluble protein at the high initial algal cell density was increased, antioxidant enzymes systems were affected, NR activities was inhibited, and the 39.8 kDa protein disappeared in N. minor treatments. The morphology of S. obliquus showed no difference in the macrophyte treatments and the controls, and the cultures were dominated by 4-celled coenobia. Chl a content of N. minor was not significantly affected. The results indicated N. minor had significant allelopathic effects on the growth and physiological processes of S. obliquus, while S. obliquus exhibited no allelopathic effect on Chl a content of N. minor.No allelopathic growth inhibition of S. obliquus was detected in the tests using culture filtrates of the macrophyte. P-limited or N-limited S. obliquus was no more sensitive to filtrates than nutrient-sufficient S. obliquus.2. The OD650, cell numbers and Chl a-based growth and photosynthetic rates of S. obliquus at two different initial cell densities were obviously suppressed by P. malaianus in the coexistence experiments. Moreover, the inhibition was dependent on the biomass density of P. malaianus. Total soluble protein, MDA, antioxidant enzymes (SOD, CAT and POD), NR, APA, protein electrophoretic pattern and morphology of S. obliquus were determined after the co-culture experiments were terminated. The activities of SOD, CAT, POD, and APA at the low initial algal cell density were stimulated, the contents of MDA and total soluble protein were increased, and some special protein bands disappeared in P. malaianus treatments, while NR activity rose only in 3.75 g/L P. malaianus treatment. The macrophyte had no effect on the activities of SOD, NR and APA at the high initial algal cell density, but significantly influenced other physiological parameters of S. obliquus with the increase of biomass density. Algal cell morphology showed no difference in the macrophyte treatments and the controls, and the cultures were dominated by 4-celled coenobia. The results indicated P. malaianus had significant allelopathic effects on the growth and physiological processes of S. obliquus, while S. obliquus at the lower initial cell density exhibited positive allelopathic effect on Chl a content of P. malaianus. Filtrates from plant co-cultured with S. obliquus at the low initial cell density exhibited no apparent growth inhibitory effect on S. obliquus.No allelopathic growth inhibition of S. obliquus was detected in the tests using culture filtrates of the macrophyte. The sensitivity of P-limited S. obliquus was not higher to filtrates than for P-sufficient S. obliquus.3. The OD650, cell numbers and Chl a-based growth of S. obliquus at two different initial cell densities was significantly inhibited by P. crispus in the coexistence experiments. S. obliquus at the high intial cell density forms more colonies in the treatments at the first 5 days incubation. The morphology of S. obliquus showed no difference in the macrophyte treatments and the controls on the last day of the experiments, and the cultures were dominated by 4-celled coenobia. Photosynthetic rate of S. obliquus at the lower initial cell density was inhibited with promotion of the biomass of P. crispus. The activities of POD and APA at the low initial algal cell density were stimulated, the content of total soluble protein was increased in 2.5 and 3.75 g/L P. crispus treatments (the 15.1 kDa protein disappeared in 3.75 g/L P. malaianus treatment). Total soluble protein and MDA contents at the high initial algal cell density were increased, CAT and APA activities were stimulated, and NR activity was inhibited in 3.75 g/L P. crispus treatment, while total soluble protein content was increased, antioxidant enzymes systems were affected, and APA activity was inhibited in 5 g/L P. crispus treatment. Chl a content of P. crispus was not significantly affected. The results indicated P. crispus had significant allelopathic effects on the growth and physiological processes of S. obliquus, while S. obliquus exhibited no allelopathic effect on Chl a content of P. crispus.Allelopathic growth inhibition of P-limited S. obliquus was detected in the tests using filtrates of the macrophyte cultivated in no nutrient.4. The growth of N. hantzschiana at two different initial cell densities was significantly inhibited by N. minor in the coexistence experiments, and the lower initial cell density was almost dead on day 1. Total soluble protein, MDA, antioxidant enzymes (SOD, CAT and POD), NR, APA and protein electrophoretic pattern of N. hantzschiana at the high initial cell density were measured after the co-culture experiment was terminated. Total soluble protein content of N. hantzschiana was decreased, and CAT activity was inhibited in 2.5 g/L N. minor treatment. MDA content was reduced in 3.75 g/L N. minor treatment. Other physiological parameters were not affected by the macrophyte. Chl a content of N. minor was significantly affected. The results indicated N. minor had significant allelopathic effects on the growth and physiological processes of N. hantzschiana, while N. hantzschiana exhibited negative allelopathic effect on Chl a content of N. minor. No allelopathic growth inhibition of S. obliquus was detected in the tests using culture filtrates of N. minor.The two different initial algal cell densities in P. malaianus treatments were almost dead on day 4.The growth of N. hantzschiana at two different initial cell densities was significantly inhibited by P. crispus in the coexistence experiments, and the lower initial cell density was almost dead on day 3. Total soluble protein, MDA, antioxidant enzymes (SOD, CAT and POD), NR, APA and protein electrophoretic pattern of N. hantzschiana at the high initial cell density were measured after the co-culture experiment was terminated. The activities of antioxidant enzymes (SOD and POD), NR and APA were stimulated, the content of total soluble protein was increased, and the 56.4 kDa protein disappeared in 2.5 g/L P. crispus treatment. Antioxidant enzymes (CAT and POD), NR and APA activities were significantly induced, and the 56.4 kDa protein disappeared in 3.75 g/L P. crispus treatment. Chl a content of P. crispus was not significantly affected. The results indicated P. crispus had significant allelopathic effects on the growth and physiological processes of N. hantzschiana, while N. hantzschiana exhibited no allelopathic effect on Chl a content of P. crispus. Allelopathic growth inhibition of P-sufficient and P-limited N. hantzschiana was detected in the tests using filtrates of the macrophyte cultivated in no nutrient.5. The growth of M. aeruginosa at two different initial cell densities was significantly inhibited by the three macrophytes in the coexistence experiments. The algal cells in the treatments died after 3 or 4 days of co-cultures.Allelopathic growth inhibition of M. aeruginosa was detected in the tests using culture filtrates of the three macrophytes. The filtrates of three macrophytes under nutrient-sufficient conditions showed significant allelopathic effects on the growth of M. aeruginosa. The filtrate of P. malaianus with aerated treatment was more significant growth inhibitory effect on M. aeruginosa than with not-aerated treatment. The initial or quasi-continuous addition filtrates of root-cutting and root-remaining P. crispus showed significant allelopathic effects on the growth of M. aeruginosa. However, under nutrient-limited conditions, the filtrate of P. crispus had positive allelopathic effect on the growth of M. aeruginosa. P-limited M. aeruginosa was more sensitive to filtrates than P-sufficient M. aeruginosa. Intact P. crispus showed inhibitory effect on the growth of M. aeruginosa.The results indicated that three macrophytes showed significant allelopathica effects on the growth of M. aeruginosa.6. From December, 2004 to May, 2005 phytoplankton was investigated monthly in the process of the aquatic vegetation rehabilitation in Lake Yuehu, Wuhan. The result indicated that, under the condition of the very high nutrition concentrations, phytoplankton was still maintained at the very low biomass and density; phytoplankton growth was positively correlated with the temperature, but not with nutrient concentrations. P. cripus (including Elodea canadensis) made water body maintain higher transparency. The species of water bloom did not appear with the increase of temperature under the condition of high nutrition concentrations and transparency. The phytoplankton community structure was possibly changed by aquatic plants.更多还原