【作者】 刘伟；

【导师】 徐亚同； 何国富；

【作者基本信息】 华东师范大学 ， 环境科学， 2012， 博士

【摘要】 喜旱莲子草作为一种外来入侵植物,现己成为世界性恶草,对入侵地造成了严重的生态破坏、经济损失和社会影响。亟需寻找一种生态安全、经济有效的综合防治措施。本研究依托国家十一五“水体污染控制与治理”科技重大专项课题---南四湖退化湿地生态修复及水质改善技术与示范课题,以喜旱莲子草的综合防控为研究目的,以替代控制和资源化利用为突破口,通过对喜旱莲子草在山东省南四湖流域的入侵现状调研、芦苇替代控制喜旱莲子草技术及机理、喜旱莲子草基活性炭制备等的研究,以期实现对山东省南四湖流域喜旱莲子草的有效防控,并为我国北方地区喜旱莲子草的治理和资源化利用提供借鉴与指导。通过对山东省南四湖流域的现场踏勘和系统调研,结果表明：山东省南四湖流域喜旱莲子草的断面出现率达71.1%,正处于由入侵阶段向定居阶段甚至稳定阶段的过渡时期；该区域喜旱莲子草的分布受流域的经济发展状况、河道水文、水质、生态条件及驳岸类型的影响较大,而纬度的影响不大；喜旱莲子草在该区域的入侵,对南四湖流域的渔业、河流及湖泊的水质、生物多样性、行洪防洪存在着较大潜在风险。在小沙河下游进行芦苇替代控制喜旱莲子草的中试试验表明：芦苇替代控制技术有效的抑制了喜旱莲子草的生长。中试试验实施后,喜旱莲子草由毯状形态变为单株,且株长、生物量、覆盖度均有较大程度的降低。8月份的覆盖度由2009年的30.0%降至2011年的5.9%,降低了24.1个百分点。中试试验实施后,喜旱莲子的平均株长由2.0m(2009年8月)降低到0.6～1.0m(2011年8月)；中试试验对于试验河道的水质有较好的改善效果。2010年5月到2011年11月,出水COD、NH3-N、TN、P043-p、TP的平均值分别为：26.00mg/L、1.43mg/L、5.40mg/L、0.21mg/L、0.47mg/L,平均去除率分别为：33.9%、35.1%、9.7%、20.1%、16.3%；中试试验实施后,试验河道的生物多样性得到有效的提高。从浮游藻类的数量上看,由实施前的94种增加到101种,细胞丰度有所降低,而生物多样性则增加明显,入湖口处的Shannon-Weaver生物多样性指数由1.17增加到3.0,表明河道水质从中污染向轻污染过渡。芦苇仿生植物与喜旱莲子草的共生实验结果表明：喜旱莲子草的根、茎、叶对遮荫的响应表现出较强的表形可塑性,因而地面上对光的竞争对喜旱莲子草的生物量影响不明显。化感方面,则展开了芦苇水提液对喜旱莲子草发芽、幼苗生长的影响实验。结果表明,化感作用是芦苇替代控制喜旱莲子草的主要作用。分析芦苇水提液对喜旱莲子草的叶绿素含量及比例、类胡萝卜素含量、酶活、根系活力、氮磷等营养物的含量等方面的影响表明：水生喜旱莲子草受到的化感抑制作用明显高于土生喜旱莲子草；随着处理浓度的增加,抑制效应随之增强,其在土生境中符合赫米西斯效应,即低促高抑的双重效应,而在水生条件下,主要表现为抑制效应；芦苇水提液对喜旱莲子草的发芽影响明显,水生境发芽数的RI在50%的处理浓度下为-0.87,土生境的RI为-0.40；而最早发芽天数较对照组均有推迟,最长芽长、单株高多芽数的RI值也表现为抑制；芦苇水提液对于幼苗生长的化感作用主要表现是生物量明显降低；芦苇水提液对喜旱莲子草的叶绿素含量表现为抑制作用；处理浓度为20%、50%的情况下,喜旱莲子草的类胡萝卜素含量较对照组低,化感抑制作用随着胁迫时间的增加先减弱后增强。在胁迫时间内,水生境、土生境中喜旱莲子草类胡萝卜素的含量较对照组平均降低43.J%和38.3%；在水生境下,喜旱莲子草的根系活力受到较强的抑制效应,而对于土生境下的喜旱莲子草的根系活力则影响不大；喜旱莲子草的过氧化氢酶(CAT)活性受到明显抑制,且随处理浓度的加大、胁迫时间的增加而呈现增强的趋势；芦苇水提液对喜旱莲子草丙二醛(MDA)存在显著的促进作用；芦苇水提液对喜旱莲子草的氮磷含量影响在不同的生境下有一定差异。综上,芦苇水提液的化感作用机理是：当芦苇水提液作用于喜旱莲子草植株后,引起了喜旱莲子草体内活性氧代谢系统失衡,破坏或降低活性氧清除剂,增加活性氧的产量,从而破坏了膜结构,降低了喜旱莲子草的叶绿素含量及类胡萝卜素含量,进而影响了光合作用,降低了喜旱莲子草的根系活力,并影响了喜旱莲子草根系对N、P等营养元素以及其它物质的吸收,最终表现为抑制喜旱莲子草的发芽和幼苗的生长发育。喜旱莲子草制备活性炭的结果表明：综合得率和碘吸附值考虑,三种活化剂中磷酸最做优,在浸渍比为1：4、浸渍时间为6h、制备温度为600℃、制备时间为1h的条件下,磷酸制得的活性炭的得率为37.44%,碘吸附值为752.36mmg/L;N2-吸附脱附等温线判定,活性炭样品孔径主要集中于中孔范围,孔道是狭窄的楔形孔。通过BET方程、BJH等方法计算,活性炭样品的比表面积为1100.72m2/g,总孔容为0.61cm3/g,平均孔径为2.22nm,孔径分布主要集中在2-5nm,中孔率为72%；通过傅立叶变换红外光谱仪分析,该活性炭样品中含有羧基(-COOH)、酚、烯基(-C=C)、醇羟基(R-OH)、胺基、醚基(-C-O-C)等含氧、含氮官能团；通过XRD衍射分析表明,活性炭中部分碳原子已形成较稳定的片层石墨晶体结构,但部分仍为无定形态,从而使得片层间隙增大,增加了活性炭的比表面积；通过SEM微观分析,制备的活性炭孔径以中微孔为主,表面存在发达的孔径,且孔径大小不一,呈椭圆形、裂缝形或不规则形等多种形状,而表面形态呈现凹凸不平、蜂窝状结构;活性炭对重金属的吸附实验表明：从吸附效率上看,对Fe(Ⅲ)平均吸附效率在60%以上,对Cu(Ⅱ)的吸附效率平均在40%以上。更多还原

【Abstract】 As an exotic invasive plants, alligator weed, Alternanthera philoxeroides (Martius) Grisebach, has become the world’s evil nature grass. Its invasion has caused serious ecological damage, economic losses and social impact. It is urgent to find an eco-safe, cost-effective measures to control its invasion. This study relies on the National Eleventh Five-Year "water pollution control and governance of major science and technology topics---Nansi degradation of wetland ecosystem restoration and water quality improvement technology and demonstration of subject (one of the subjects of the Huaihe River Basin water pollution control technology research and integrated demonstration projects). The purpose of this study is to invent a comprehensive technology to control and utilization alligator weed. Based on the status research of alligator weed in Shandong Province Nansihu basin, the method and mechanism of reed alternative control and the preapared way of activated carbon were researched. This research will guide the control of alligator weed in Nansi Lake basin, Shandong Province, even northern China.The results of site survey and system research in Nansi Lake Basin, Shandong Province showed that:the section rate of of Alternanthera philoxeroides in Shandong Province Nansihu basin was up to71.1%. And the basin was in the transitional period by the invasion phase of stable phase or even to settle in stage. The distribution of Alternanthera philoxeroides in the region was effected by the economic development of the basin, river hydrology, water quality, ecological conditions and revetment. Alternanthera philoxeroides invasion in the region leaded to large potential risks on the aspect of fisheries, rivers and lakes of the Nansi Lake basin water quality, biodiversity and flood control.The reed alternative control of Alternanthera philoxeroides with a pilot in the Xiaosha river downstream showed that:reed alternative control technology effectively inhibited the growth of Alternanthera philoxeroides. Before and after the implementation of the demonstration project, Alternanthera philoxeroides by the blanket-like shaped into a single plant. And plant length, biomass, coverage had a higher degree of reduction. In August, the coverage dropped from30percent in2009to5.9percent in2011, with a24.1percent reduction. Before and after the implementation of the demonstration project, xerophilous alligator weed plant length by2m in August (2009) reduced to0.6-1.0m in August (2011). The demonstration project of test river water also enhanced the water quality. From May2010to November2011, the average of the effluent of COD, NH3-N, TN, PO43--P, TP were as follows:26.00mg/L and1.43mg/L,5.40mg/L, and0.21mg/L,0.47mg/L, and average removal rates were:33.9%,35.1%,9.7%,20.1%,16.3%.The pilot river biodiversity had been effectively improved which meant the number of planktonic algae from the point of view was decreasing, before the implementation of the94kinds to101kinds of cell density, and biodiversity was increased significantly, and the estuary at the Shannon-Weaver biodiversity index increased from1.17to3.00, indicating that the river water quality was from pollution in the transition to light pollution. Reed bionic plant and Alternanthera philoxeroides mixed experimental showed that there were strong phenotypic plasticity of Alternanthera philoxeroides roots, stems, and leaves in respense to shade. Aquatic alligator weed by allelopathic inhibition was significantly higher than xerophilous alligator weed; Under the concentration of50%, the extract of reed had significant impact on germination of alligator weed. In hydroponics habitat conditions, the RI(allelopathic effect index. If positive, it means the performance role in promoting and the greater its value, the stronger allelopathic to promote. If negative, it means the inhibitory effect and the higher absolute value, the stronger the suppression effect was-0.87. In xerophilous habitat conditions, RI was-0.4. comparing to control group, the first germination days were all postponed under the allelopathic effect. During stress time, carotenoid content of Alligator weed in hydroponics habitat and xerophilous habitat decreased on the average of43.1%and38.3%respectively. The extract of reed had a strong inhibitory effect on the root activity of Alligator weed under the hydroponics habitat,while has little impact on that growing under native habitat. In hydroponics habitat conditions, the average allelopathy index was-0.81on root activity and the inhibition increased with the increasing of concentration of extract of reed. The extract of reed had inhibition effect on the activity of catalase (CAT), which indicated that the inhibition effect had a trend of strengthen with the increasing of concentration of reed extract and stress time. It meant the growing of concentration and sress time increased the inhibition of CAT activity, which accelerated the inactivation of enzyme. The extract of reeds had some differences effect on the contents of nitrogen and phosphorus of alligator weed in the different habitats. In xerophilous habitat conditions, the content of P decreased rapidly with the increasing of concention.In summary, the reeds and water extracts of Allelopathy Mechanism were that when the extract of reed acted on Alternanthera plant drought, it causes the imbalance of reactive oxygen species metabolic system in alligator weed, damaged or reduced the reactive oxygen species scavenger, increased production of reactive oxygen species and destroyed the mambrane strunture. Besides, it also reduced the chlorophyll and carotenoid content of alligator weed, thus affecting photosynthesis and root activity, and affected the root absorption of N and P, as well as other substances, thus inhibiting the germination and seedling growth and development of alligator weed.In order to improve resource utilization of Alligator weed, this paper explores the preparing process of activated carbon by Alligator weed under different activatior and conditions and studies the feasibility of optimal conditions. With phosphoric acid as an activator, the optimum preparation conditions were activation temperature600℃, activation time1h, impregnation1:4, soaking time12h. Under this condition, the yield of activated carbon was37.44%and adsorbtion of I2was752.36mg/L. According to the analysis of FTIR, the activated carbon samples containing such functional groups:carboxyl (-COOH), phenol, alkenyl (-C=C), alcoholic hydroxyl group (R-OH), amine, ether (-C-O-C), and so on. The XRD diffraction analysis showes that some carbon atoms in the activated carbon were in the formation of more stable crystal structure of the lamellar graphite, but some was still amorphous, making the lamellar gap increases, which increased the surface area of activated carbon. Determining by N2adsorption-desorption isotherms, the adsorption type of activated carbon sample was the type IV isotherm with a hysteresis loop of type H4. That indicates that pore size was mainly concentrated in the mesoporous range and the channel is a narrow wedge-shaped hole. Calculated by the BET equation and BJH methods, specific surface area of activated carbon samples was1100.720m2/g and its total pore volume was0.610cm3/g with average pore size of2.216nm, which also showed that the activated carbon mainly in the mesoporous range. The pore size distribution was mainly concentrated in the2-5nm and the rate of mesoporous range was72.0%.The analysis of SEM showed that the surface of activated carbon had developed aperture and aperture had various sizes, showing a variety of shapes of oval, crack-shaped or irregular in shape, in which the pore size was mesoporous range. The surface morphology of activated carbon is rough, showing the concave and convexuneven, honeycomb-like structure.The results of activated carbon adsorption of Fe (Ⅲ) showed that average adsorption efficiency was above60%and adsorption of Cu (Ⅱ) showed that average adsorption efficiency was above40%.更多还原