【作者】 曹海芹；

【导师】 常杰； 葛滢；

【作者基本信息】 浙江大学 ， 生态学， 2010， 硕士

【摘要】 人工湿地是一种新型的废水处理生态技术,已经在世界范围广泛推广。人工湿地处理的不同来源的污水具有极大的NO₃^-/NH₄⁺比例差异性。植物是人工湿地重要角色,但不同种类的植物对NO₃^-和NH₄⁺具有不同的偏好和耐受性,所以选择合适植物种类应用于人工湿地污水处理中非常重要。本文通过实验研究了6种人工湿地常见植物对不同氮形态的响应,并整合文献数据分析了不同分类群植物对NO₃^-和NH₄⁺的偏好特点。此外,本文还比较分析了水培和沙培条件下植物生长的不同表现,以说明人工湿地基质微生物的作用。研究结果表明:1.在NO₃^-/NH₄⁺混合比例75/25和50/50下,黑麦草、美人蕉和菩提子地上、地下及整株生物量均大于纯NO₃^-和纯NH₄⁺处理,高NH₄⁺处理对生长抑制更强。菖蒲整株、地上和地下生物量也在NO₃^-/NH₄⁺混合比例50/50下最大,但在纯NO₃^-下最低,且根在纯NH₄⁺下无抑制,表现出对NH₄⁺的忍耐性。黄菖蒲和吉祥草在纯NO₃^-下生长最佳,生物量随NH₄⁺比例的增加而降低,可见黄菖蒲和吉祥草属偏好NO₃^-但不耐NH₄⁺。植物组织氮积累量与生物量之间显著相关,但与氮浓度相关性弱,因而可以根据生物量指标来选择人工湿地植物。2.整合文献数据发现,国内外研究过的绝大多数物种在NO₃^-下生物量要大于NH₄⁺下的生物量,少数物种在NH₄⁺下的生长好于NO₃^-条件下,纯NO₃^-和纯NH₄⁺下生物量之比大于1的物种约占80%。目前发现的NO₃^-偏好的植物出现在茄科、葫芦科、菊科、豆科、藜科、十字花科、杨柳科、蔷薇科、大戟科、荨麻科、天南星科、鸢尾科、美人蕉科、唇形科和禾本科的一些种类中,NH₄⁺偏好的植物出现在百合科、杜鹃花科、松科、壳斗科、莎草科、山龙眼科、红豆杉科、桃金娘科、山茶科、凤仙花科和禾本科的一些种类中。有些科既有NO₃^-偏好,也有NH₄⁺偏好,如禾本科,NO₃^-偏好种类有黑麦草、菩提子、小麦和玉米,NH₄⁺偏好种类有水稻、白茅。同属植物对NO₃^-/NH₄⁺比例的响应也存在差异,石荠苧属6种植物在纯NH₄⁺下只有疏花荠苧能存活到实验结束,但其各部分生物量都最低,石荠苧属植物总体表现出偏NO₃^-可见分类群与无机氮化学形态偏好没有紧密相关性,这种偏好是生态适应功能群的具体表现。3.在氮移除能力方面,黑麦草、美人蕉、菖蒲和菩提子的植物组织氮积累量在混合NO₃^-/NH₄⁺下最大,极端氮形态处理下的氮积累量明显减少。在纯NO₃^-处理下,黄菖蒲地上地下氮积累量最高,NH₄⁺比例越多,黄菖蒲组织氮积累量越低。纯NH₄⁺处理下的吉祥草叶、根氮积累量明显低于其余4个含NO₃^-的氮形态处理,且其余4个处理未表现出显著差异。5在微生物活动存在的沙培条件下,美人蕉和菩提子在纯NH₄⁺条件下的叶、茎和根生物量均低于NO₃^-/NH₄⁺混合比例50/50。在生物量分配方面,沙培条件下的美人蕉和菩提子的R/S均显著大于水培条件。与生物量类似,两种栽培条件下的美人蕉和菩提子在NO₃^-/NH₄⁺混合比例50/50下的整株绝对生长速率均大于纯NH₄⁺处理。然而,在沙培条件下,NO₃^-/NH₄⁺比例50/50和0/100下整株绝对生长速率的差距要小于水培条件,沙培一定程度上缓解了NH₄⁺对美人蕉和菩提子的抑制作用,说明沙基质中的微生物起了作用。综合以上方面的研究,本研究筛选出一些高效脱氮植物。可根据人工湿地废水来源优化人工湿地的植物配置,并可配置成多样化的植物群落来充分利用各种氮形态资源,充分利用不同植物的功能优势,改善人工湿地的净化效果。此外,本文还结合文献数据总结发现植物对氮形态的偏好和忍耐性状与植物分类群无必然联系,而是主要与生态功能群有关,即主要取决于植物物种在生态系统中的功能作用,从而拓宽了生物多样性-生态系统功能关系的理论基础。更多还原

【Abstract】 Constructed wetlands （CWs） are a natural alternative to technical methods of wastewatertreatment, and have been widely applied for wastewater purification. Wastewater from differentsources has different NO₃^-/NH₄⁺ ratios. Plant species may have different preferences between NO₃^-and NH₄⁺, so species should be carefully selected according to the inorganic N composition ofwastewater. Considering the importance of plants in CWs, this paper studied various respondings ofsix commonly used plants in CWs to different NO₃^-/NH₄⁺ ratios and analyzed how the plants ofdifferent families responded to the N forms. Besides, considering the importance of microorganismsin the substrate in CWs, we also compared plant growth performances under sand and solutionculture supplied with different NO₃^-/NH₄⁺ ratios.The shoot, root and total dry matter （DM） of Lolium perenne, Canna indica and Coixlacryma-jobi were significantly higher under NO₃^-/NH₄⁺ ratios 75/25 and 50/50 than those under100%NO₃^- and 100%NH₄⁺ treatments. Morever, compared with 100%NO₃^-, shoot and root DM ofthose plants were much lower under 100%NH₄⁺ treatment. For Acorus calamus, shoot and root DMshowed the same trend, with NO₃^-/NH₄⁺ ratios 50/50 the highest and the 100%NO₃^- lowest. However,this study didn’t find growth inhibitions for Acorus calamus under 100%NH₄⁺ treatment. For Irispseudacorus and Reineckia cornea, both shoot and root DM linearly declined with the increasingproportion of NH₄⁺. There are positive correlations between shoot DM and shoot N accumulationand between root DM and root N accumulation for all species. But N concentration was notcorrelated with N accumulation in shoot or root for most species except Acorus calamus. So plantDM should be a main factor contributing to their N removal abilities in CWs.After comprehensive analysis of the related N form studies, we found that most plants got moreDM under NO₃^- condition than NH₄⁺ condition. Solanaceae, Cucurbitaceae, Asteraceae, Fabaceae,Chenopodiaceae, Brassicaceae, Salicaceae, Rosaceae, Euphorbiaceae, Urticaceae, Araceae, Iridaceae,Cannaceae, Labiatae and some Gramineae prefer NO₃^-, while Alliaceae, Ericaceae, Pinaceae,Fagaceae, Cyperaceae, Proteaceae, Taxaceae, Myrtaceae, Theaceae, Balsaminaceae and someGramineae prefer NH₄⁺. For Gramineae, some plants exhibit preference for NO₃^-, e.g. Loliumperenne, Coix lacryma-jobi and Triticum aestivum and some plants prefer NH₄⁺, e.g. Oryza salivaand Glyceria maxima. Six plants of Mosla showed various respondings to different NO₃^-/NH₄⁺ ratios.Only Mosla pauciflora survived in sole NH₄⁺ treatment, other five plants died before harvest time,showing preference for NO₃^-. So the relationship between plant taxa and N form is not obvious, andecological adaptive functional groups play greater roles.Concerning the N removal abilities of different plant species, Lolium perenne got the most Naccumulation in both shoot and root under NO₃^-/NH₄⁺ ratios of 50/50 and 75/25, while NO₃^-/NH₄⁺ratio of 0/100 and 100/0 the lowest, which is similar with Canna indica, Acorus calamus and Coixlacryma-jobi. N accumulation in both shoot and root of Iris pseudacorus gradually declined with theincreasing proportion of NH₄⁺. Under the NO₃^-/NH₄⁺ ratio of 0/100, N accumulation in leaf and rootof Reineckia cornea is significantly lower than the other four treatments containing NO₃^-.Considering the importance of microorganisms in the substrate in CWs, we also compared plantgrowth performances under sand and solution culture supplied with different NO₃^-/NH₄⁺ ratios.Compared with sole NH₄⁺ treatment, leaf, stem, root DM and absolute growth rate （AGR） of Cannaindica and Coix lacryma-jobi were significantly higher under the mixed NO₃^-/NH₄⁺ ratio of 50/50.Root/shoot （R/S） was higher for both species grown in sand than that in nutrient solution.Furthermore, we found that the reduced gap of AGR between NO₃^-/NH₄⁺ ratios 0/100 and 50/50 was smaller in sand than that in nutrient solution. Compared with solution culture, plants grown in sandshowed slighter growth depressions, suggesting that microorganisms in sand played important rolesin the N transformation.The whole study analyzed both growth status and N removal abilities of several commonly usedplants in CWs supplied with different ratios, aiming to select and allocate plant species andbiodiversity groups that are highly efficient in removing N. We also analyzed how plants of differentfamilies responded to different N forms and have reached a primary classification, establishingtheoretical basis for species structure optimization in CWs and thus give implications for improvingN removal efficiency. Morever, we found that plants’ preference and tolerance for NO₃^- or NH₄⁺ wasnot depend on plant taxa, but mainly related to the ecological functional groups. The study laid asolid theoretical foundation for the research about biodiversity-ecosystem function relationship.更多还原