【作者】 张彦辉；

【导师】 杨劭；

【作者基本信息】 华中师范大学 ， 微生物学， 2008， 硕士

【摘要】 无机碳是绿色植物进行光合作用的基本资源。溶解于水体中的无机碳共有三种不同的存在形式:自由CO₂（溶解于水中的分子形式为CO₂和H₂CO₃）、离子态的HCO₃^-和CO₃^2-。近年来发现几乎所有沉水植物的内在光合作用潜力都远远超过水体无机碳的供应量,大部分沉水植物的生长经常受到无机碳的潜在限制。为了解水华引起的水体无机碳变化对沉水植物生长的影响,对8种沉水植物:金鱼藻,穗花狐尾藻,篦齿眼子菜,光叶眼子菜,微齿眼子菜,伊乐藻,菹草和黑藻在不同无机碳浓度下的生物量、株高、叶绿素以及光合和呼吸速率进行了比较研究。结果表明8种沉水植物均能利用HCO₃^-作为光合无机碳源,外源HCO₃^-浓度在1.5 mmol/L下时能促进金鱼藻、菹草和伊乐藻的生长,提高其光合速率;外源HCO₃^-浓度在2.5 mmol/L下时能促进狐尾藻、光叶眼子菜、黑藻、微齿眼子菜和蓖齿眼子菜的生长,提高其光合速率。在CO₃^2-为优势碳源时,8种沉水植物表现出不同的适应性,发现微齿眼子菜、篦齿眼子菜和黑藻在整个实验范围内生长未受抑制,且在不同浓度下表现生长和光合速率的提高,说明这三种沉水植物对[HCO₃^-]/[CO₃^2-]比值和pH值具有较广适应范围。而金鱼藻和伊乐藻的生长受到抑制,狐尾藻,菹草和光叶眼子菜均死亡,表明[HCO₃^-]/[CO₃^2-]比值和pH值是这5种沉水植物生长的重要限制因子。通过添加无机碳和曝气的方式改变滇池水体无机碳构成比例的方法,研究了沉水植物篦齿眼子菜,穗花狐尾藻,微齿眼子菜,光叶眼子菜和马来眼子菜在野外条件下种群扩增,以及对水体无机碳的适应性,结果表明添加4.0 mmol/L无机碳能促进篦齿眼子菜和微齿眼子菜的生长,添加0.5 mmol/L无机碳明显促进狐尾藻的生长,夜间曝气的方式一定程度上可以降低水体叶绿素a浓度,抑制藻类的生长。以滇池福保湾生态恢复区非封闭性围隔和围隔外水域为研究对象,研究了富营养化水体中可溶性无机碳的时空动态变化及其相关影响因素,来探索蓝藻水华爆发至消亡过程中水体无机碳在自然水体中的变化规律。结果表明:福保湾水体叶绿素a浓度和CO₃^2-浓度呈极显著正相关（P＜0.01）,与CO₂浓度均呈极显著负相关（P＜0.01）,与总无机碳浓度和HCO₃^-浓度均呈显著负相关（P＜0.05）;水体叶绿素a浓度与水体pH值均呈显著正相关（P＜0.05）。更多还原

【Abstract】 Dissolved inorganic carbon（DIC）is a fundamental resource for photosynthesis of plants.The forms of DIC in water include CO₂,HCO₃^- and CO₃^2-.Recent studies have shown that DIC potentially limited the growth and photosynthesis of several submerged macrophytes.In order to elucidate the impacts of variation of DIC caused by water bloom on the growth of submerged macrophytes,the biomass,shoot length,chlorophyll and photosynthetic and respiration rates of eight kinds of submerged macrophytes,including Ceratophyllum demersum L.,Myriophyllum spicatum L.,Potamogeton pectinatus L., Potamogeton lucens Linn.,Potamogeton maackianus,Elodea nattalii,Potamogeton crispus and Hydrilla verticillata,were analysed under different DIC conditions.The results indicated that HCO₃^- can be utilized as carbon source by all the submerged macrophytes tested.Improvement of growth and photosynthetic rates was found on Ceratophyllum demersum L.,Potamogeton crispus L.and Elodea nattalii under exogenous HCO₃^- below 1.5 mmol/L,and also on Myriophyllum spicatum L., Potamogeton lucens Linn.,Hydrilla verticillata,Potamogeton maackianus and Potamogeton pectinatus L.under exogenous HCO₃^- below 2.5 mmol/L.However,when CO₃^2-acts as the dorminat carbon source,different effects were found on the eight kinds of submerged macrophytes.Growth and photosynthetic rates of Potamogeton maackianus,Potamogeton pectinatus L.and Hydrilla verticillata were not inhibited,and were improved at certain CO₃^2-concentration,which indicates the three species of macrophytes adapt to a wide range of[HCO₃^-]/[CO₃^2-]ratio and pH value.However,the growth of Ceratophyllum demersum L.and Elodea nattalii were inhibited,and Myriophyllum spicatum L.,Potamogeton crispus L.and Potamogeton lucens Linn.died when CO₃^2-as dominate carbon source,indicating[HCO₃^-]/[CO₃^2-]ratio and pH values were the important limiting factors of growth for the above 5 species of submerged macrophytes.In the field enclosure experiment,the biomass change of five kinds of submerged macrophytes,including Potamogeton pectinatus L,Myriophyllum spicatum L, Potamogeton maackianus,Potamogeton lucens Linn.and Potamogeton malaianus,were analysed by change the DIC with air aeration and supplement of bicarbonate.It is found that the growth of Potamogeton pectinatus L.and Potamogeton maackianus, Myriophyllum spicatum L were improved under exogenous HCO₃^- at 4.0mmol/L and 0.5mmol/L respectively.Aeration reduced the Chlorophyll a of water and inhibited algae growth considerably. In order to elucidate the variation of DIC caused by water bloom,the variation of DIC content and correlated environment factors in different enclosures of Fubao Bay of Lake Dianchi were analysed.The results indicated that the concentration of Chlorophyll a in Fubao Bay was positively correlated to CO₃^2-（P＜0.01）and pH（P＜0.05）,negatively correlated to CO₂（P＜0.01）,DIC and HCO₃^-（P＜0.05）,respectively.更多还原