【作者】 刘睿；

【导师】 陶宗娅；

【作者基本信息】 四川师范大学 ， 生物化学与分子生物学， 2010， 硕士

【摘要】 摘要：浮萍是一种小型水生漂浮植物,生长迅速且容易获得,对生长条件要求低,吸收N、P的能力强,可以作为一种比较理想的治理水体富营养化的选材。本文以紫背浮萍(Spirodela polyphiza)为试材,分别采用N、P、La3+单因素培养,复合培养及四因素、三水平正交设计[L27(34)]水培体系,研究浮萍生长和繁殖过程中通过其吸收N、P而达到净化富营养化水体的若干未知机制以及La3+在其中的作用,为发展新型的水体富营养化治理技术提供理论和实践依据。主要研究结果如下：1.浮萍生长和繁殖过程中能够吸收水体中的N、P从而起到净化富营养化水体的作用；当培养液的N浓度为10～50mg/L、P浓度为0.5～8mg/L范围内,浮萍吸收N、P的能力随N、P浓度增加而提高；在N浓度为50mg/L、P浓度为15mg/L条件下培养,浮萍生长及净化水体的效果最佳。2.浮萍净化水体的能力与浮萍生长状况有密切关系,而培养时间是决定浮萍生长状况的最主要因素,本实验体系中培养6d时的浮萍生长状况最好。3.浮萍叶绿素b含量对体内La3+含量变化敏感,培养液中La3+浓度为1.0mg/L时,浮萍体内La3+含量达到181μg/g FW,此时叶绿素b含量显著增加,达0.2mg/g FW,比对照组(CK,0.14mg/g FW)提高42.9%,暗示La3+可能通过促进合成天线色素而上调植物光合功能；但浮萍体内La3+含量对叶绿素a及类胡萝卜素含量的影响不显著。当浮萍体内La3+含量达到181μg/g FW时,浮萍SOD比活性[18.16U/(min·mgPr.)]则显著下降,比CK组[26.29U/(min·mg Pr.)]降低30.9%,O2-产生速率显著上升,达16.03μg/(min·g FW),比CK组[12.68μg/(min·g FW)]增加26.4%；同时,浮萍NR活性[39.23μg/(h·g FW)]显著下降,比CK组[42.1μg/(h·g FW)]下降6.8%。表明随着水体中La3+浓度的提高,浮萍体内的La3+逐渐积累,浮萍体内活性氧代谢和氮代谢出现紊乱,导致其可能受到潜在的过氧化伤害。综上结果表明,水体中一定浓度的La3+能够促进浮萍的生长和代谢,从而有利于利用浮萍生长和繁殖净化富营养化水体,但La3+浓度超过1.0mg/L时,La3+对浮萍生长和代谢的抑制作用显现,存在强化水体富营养化的潜在可能性。更多还原

【Abstract】 Abstract:Ducekweed(Spirodela polyphiza) is a kind of aquatic plant. It grows rapidly and is easy to get. It has high capability to absorb nitrogen and phosphorus in water. Duckweed is a good target to control water eutrophication.The studies tried to understand the mechanism of La3+ in medium for cultivating duckweed on affacting absorb N, P from the medium. The experimental system contained (1)differnt N, P and La3+ concentration respectively, (2) complex of differnt N, P and La3+ concentration, (3) orthogonal design of three factors and four levels for differnt N, P and La3+ concentration. The main results were as follows:1. Eutrophia water can be cleaned through duckweed’s growth. Duckweed’s capability to absorbing N and P increased within 10-50mg/L for N concentration and 0.5-8mg/L for P concentration. Deckweed grew best when concentration of N and P were 50g/L and 15mg/L respectively, N and P concentration in medium declined fast at the same condition.2. Duckweed’s capability to absorbing N and P associated with duckweed’s growth. Duckweed grew best for 6 days cultivation.3. Chl b concents in duckweed can be highly influented by La3+ which translated into duckweed as well. La3+ contents in duckweed reached to 181μg/g FW when La3+ concentration was lmg/L in medium. Chl b contents in duekweed (0.2mg/g FW) significantly increased for 42.9% comparing to CK (0.14mg/g FW). It suggested that photosynthesis can be up-regulated by La3+ in duckweed. Chl a and Car contents.had little changes as following La3+contents in duckweed.SOD specific activities [18.16U/(min-mg Pr.)] in duckweed significantly declined for 30.9% comparing to CK [26.29U/(min-mg Pr.)] and O2- production rate [16.03μg/(min-g FW)] significantly increased for 26.4% comparing to CK [12.68μg /(min-g FW)] and NR activities [39.23μg/(h-g FW)] in duckweed significantly declined for 6.8% comparing to CK[42.1μg/(h-g FW)] when La3+ contents in duckweed reached to 181μg/g FW. It had negative influence to ROS (reactive oxygen system) and nitrogen metabolism when La3+ contents increased in duckweed. Duckweed’s growth may be harmed by peroxidation.It is suggested that adequate La3+ concentration is good for duckweed’s growth and metabolism and also has benefit for water eutrophication controlling. But it may promote water eutrophication when La3+ concentration over 1.0mg/L.更多还原