水体浊度对菹草萌发及萌发苗光合荧光特性的影响  

Influence of water turbidity on germination of Potamogeton crispus and growth of germinated seedling

作　　者：李强[1] 王国祥[1] 潘国权[1] 王文林[1] 马婷[1] 

机构地区：[1]南京师范大学地理科学学院江苏省环境演变及生态建设重点实验室,江苏南京210097

出　　处：《生态学报》2006年第11期3594-3601,共8页Acta Ecologica Sinica

基　　金：国家863专项资助项目(2003AA601100-2);国家教育部"211工程"项目;国家教育部科技创新工程重大项目培育基金联合资助项目(#705824-2)~~

摘　　要：用粒径小于100μm的泥沙分别配置浊度为30、60NTU和90 NTU的混浊水体,将菹草(Potamogeton cripus)石芽分别种植于上述水体中,测定萌发率和萌发苗的株高、叶片数,并利用水下饱和脉冲荧光仪(DIVING-PAM)测定萌发苗的光合荧光特性。结果表明,水体浊度对石芽萌发率没有显著影响,但对萌发速率有一定影响;随着浊度的升高萌发苗株高和叶片数均显著降低(p<0.05);菹草萌发苗的有效荧光产量Yield也随水体浊度升高而降低,表明在高浊度水体中萌发苗天线色素吸收光子供给PSII反应中心的效率下降;高浊度导致萌发苗吸收光能用于光化学电子传递的份额(qP)减少,第23天时90NTU水体中的qP为对照的91.4%;水体浊度上升导致qN显著升高,表明在高浊度、低光照胁迫下,萌发苗接收的光能更多的以热的形式耗散掉了,以避免光系统PSⅡ受到过剩光能的伤害;浊度升高引起电子在光合链中的传递速率(ETR)显著下降,第23天时在30、60NTU和90NTU水体中ETR分别为对照的93.3%8、8.5%、75.8%,导致参与CO2固定的电子减少,光合作用降低。快速光响应曲线测定结果表明,萌发苗ETRmax和最小饱和光照强度随水体浊度的增加呈下降趋势,光响应能力随水体浊度的增加而显著下降,特别是在90NTU水体中萌发苗的光合作用能力下降显著。因此,在浅而混浊的水体中(水深70cm,浊度低于90NTU),菹草石芽均能萌发,但是,水体浊度对萌发苗光合作用、生长速率有一定抑制作用。Winter buds of Potamogeton crispus were planted in the waters at different turbiditoes of 30NTU, 60NTU and 90NTU which were made by sand particles less than 100μm in diameter, and the effect of water turbidity on the germinating ratio and growth were examined. Some photosynthetic fluorescence characteristics were in situ determined by a developed, submersible, pulse-amplitude modulated （PAM） fluorometer, Diving-PAM. The germinating ratio of winter buds were shown to decrease significantly as the turbidity increasing on the 10th day of the seedling exposed in turbid water （p 〈 0.05 ）. However, the germinating ratio was as high as 100.0% in all turbidities on the 23^th day. The seedling height and leaf number also decreased significantly while the water turbidity increased （p 〈 0.05 ）. The non-photochemical quenching （qN） significantly increased during the first ten-day the seedling exposed in the turbid waters, which indicated that the seedling leaves could increase heat dissipation to protect the photosystem Ⅱ （ PS Ⅱ ）. During the first ten-day when the seedling exposed in the turbid water, quantum yield （Yield）, photochemical quenching （qP） and Electron-transport rate （ETR） of seedling, were not shown to be influenced by the water turbidities. It demonstrated that photosynthesis of these seedlings was not limited by lack of light because the buds contain enough nutrients to support germination. The qP and ETR of seedling leaves were not significantly different among the turbid waters of 30, 60NTU and the control until the 23th day of turbid exposure, indicating no significant effect of the low water turbidity （30, 60 NTU） on seedling photochemical quenching and electron-transport rate. Significant decrease in the Yield of photosynthesis while the turbidity increasing （p 〈 0.05） indicated remarkable effect of turbidity on photo supplying efficiency of PS Ⅱ reaction center. Moreover, the volumes of qP, ETR and Yield of seedling leaves were much lower in the turb

关 键 词：浊度 菹草 石芽 萌发苗 光合荧光特性 

分 类 号：Q945.7[生物学—植物学]