【作者】 曹莹；

【导师】 傅大放；

【作者基本信息】 东南大学 ， 市政工程， 2018， 博士

【摘要】 湿地植物对磷有很强的富集作用,可以有效地去除环境中的磷。环境中大部分形态的磷不能被植物直接吸收,需经过分解转化,尤其是微生物的转化释放作用,成为有效磷,才能被植物吸收。因此,了解湿地根际微生物在此过程中对磷的转化释放及植物吸收的影响,是一项非常重要的基础性研究工作,可为进一步阐明湿地磷循环机制、强化湿地植物对磷素的吸收及水生态系统中磷污染的控制,提供研究基础和依据。本文以天印湖（南京,中国）湿地植物及其根际微生物作为研究对象,通过高通量测序法分析了典型湿地植物菖蒲的根际微生物的多样性组成;通过去除与保留根际微生物的植物对比实验,研究了根际微生物群落作为一个整体对水中磷的转化及植物吸收磷的影响机制;用细菌通用培养基从菖蒲、鸢尾和芦苇根际提取和纯化了根际微生物,并进一步对提取菌株的解磷释磷能力进行了测试,筛选出高效解磷菌,通过测定水中磷含量、植物生长及体内磷含量变化,研究了多种高效解磷菌的强化除磷的效果,主要创新研究结果如下:高通量测序结果表明,天印湖湿地植物菖蒲的根际微生物中,细菌的种类最多,其次是真核生物,种类数最少的是古菌。细菌中最多的是Acidobacteria（酸杆菌门）和Proteobacteria（变形菌门）分别占34.94%和34.19%,真核生物中以真菌为主,其中数量最多的是Sordariomycetes（粪壳菌）,占真核生物的37.06%,古菌中一种Candidatus Nitrosoarchaeum的氨氧化古菌含量最高,占48.07%,它们的数量优势明显。湿地根际微生物群落作为一个整体,可促进植物吸收磷,培养后有根际微生物的植物的根、茎、叶中磷含量的增量都高于被去除了根际微生物的植株。对水中有效磷、难溶无机磷、有机磷都有转化释放及促进植物吸收的作用,可以较好地促进水中总磷的去除。在对根际微生物的解磷释磷能力测定和解磷菌的筛选中发现,无机磷的溶解和释放速率远高于有机磷,且同一菌株对无机难溶磷和有机磷的释放效果不同,表明对有机磷和无机磷的溶解和释放的影响因素不同。在磷酸三钙培养基中,短期解磷速率96小时最高达0.53 mg·L^-1·h^-1,三株高效解磷菌10天解磷速率分别达到0.38 mg·L^-1·h^-1、0.50 mg·L^-1·h^-1和0.52 mg·L^-1·h^-1。不同菌种在不同培养基中释放溶解态磷量是不同的。在有机磷培养基中,短期解磷速率96小时最高为0.029 mg·L^-1·h^-1,10天解磷速率最高为0.0078 mg·L^-1·h^-1。在磷酸三钙培养基中10天后释放溶解态磷量最高达到125.88 mg·L^-1。在有机磷培养基中10天后释放溶解态磷量最高达到1.88 mg·L^-1。经鉴定在磷酸三钙培养基中从菖蒲根际筛选出的短期解磷速率较快的是Pseudomonas sp.;从芦苇根际筛出的释放溶解态磷含量最高的是Pseudomonas knackmussii。不同解磷菌对水中磷的含量以及湿地植物吸收磷的影响效果存在差异。解磷能力强的解磷菌对水中磷的去除及植物吸收磷的促进作用最为明显。植物吸收磷主要体现在叶的生长和磷含量的增加。解磷菌投加量越大,水中总磷去除率越高,植物各部分磷含量增加越明显。培养过程中,pH变化较小,在6.7⁷.1之间。本研究为利用高效解磷菌强化植物对磷的吸收,提高湿地对磷的去除效果提供了重要基础数据和基本结论。更多还原

【Abstract】 Wetland plants have a strong accumulation of phosphorus(P),which can effectively remove phosphorus in the environment.However,most forms of phosphorus in the environment can not be directly uptake by plants,and only after decomposition and transformation into available phosphorus can they be absorbed by plants.Therefore,it is a very important basic research work to understand the effect of the transformation and release and plant absorption of phosphorus on the rhiz osphere microorganisms in this process,which can provide the basis for further clarifying the mechanism of phosphorus cycling in wetland,strengthening the absorption of phosphorus and the control of phosphorus contamination in the water ecosystem.The wetland plants in Tianyin Lake(Nanjing,China)and their rhizosphere microorganisms were selected for the research.The diversity of rhizosphere microorganisms in typical wetland plant Acorus calamus was analyzed by high-throughput sequencing.The effects of rhizosphere microbial communities on the transformation of phosphorus and plant uptake by the rhizosphere as a whole are studied by removing and preserving rhizosphere microorganisms.Rhizosphere microorganisms were extracted and purified from the rhizosphere of Acorus calamus,Iris and reed with the general medium of bacteria,and the phosphorus release ability of the extracted strains was tested,and the high efficiency phosphate solubilizing bacteria were screened.Through the determination of phosphorus content in water,plant growth and phosphorus content in the plant,the effect of enhanced phosphorus removal by various high efficiency phosphate solubilizing bacteria was studied.The main innovative research results are as follows: High-throughput sequencing analysis revealed that the most aboundant domain in the studied wetland rhizosphere was bacteria,followed by eukaryotes,the least was archaea.The most bacteria were Acidobacteria and Proteobacteria,which accounted for 34.94% and 34.19% respectively.The most aboundant species of fungi were Sordariomycetes,accounting for 37.06%.An ammoxidation archaea named Candidatus Nitrosoarchaeum was the most aboundant in archea,accounting for 48.07%.They are obviously predominance.The rhizosphere microbial communities in the wetland could promote phosphorus uptake by plants,and total phosphorus of the root,stem and leave of the plants that with rhizospheric microorganisms increased more after culture.The available phosphorus,insoluble inorganic phosphorus and organic phosphorus in water can be transformed and plant absorption could be promote by the rhizosphere microbial communities,and further promoted the removal of total phosphorus in water.Inorganic phosphorus(P)-solubilizing bacteria(IPS B)and organic P-mineralizing bacteria(OPMB)were isolated rhizosphere soil of the wetland.The solubilizing of inorganic phosphorus was the major contribution to phosphorus availability,since the isolated bacteria released much more available phosphorus from inorganic tricalcium phosphate than lecithin.The same strain had different release effects on inorganic insoluble phosphorus and organic phosphorus,indicating that the factors affecting the dissolution and release of organic phosphorus and inorgani c phosphorus were different.In the medium of tricalcium phosphate,the highest short-term phosphorus solubilizing and release rate was 0.53 mg·L-1·h-1 in 96 hours,and the highest phosphorus solubilizing and release rate was 0.38 mg·L-1·h-1,0.50 mg·L-1·h-1 and 0.52 mg·L-1·h-1 in 10 days,respectively.The amount of dissolved phosphorus released by different strains in different media was diverse.In organic phosphorus medium,the highest short-term phosphorus release rate was 0.029 mg·L-1·h-1 in 96 hours and 0.0078 mg·L-1·h-1 in 10 days.The bacteria released the most dissolved phosphorus which was 125.88 mg·L-1 from tricalcium phosphate medium in 10 days,while the bacteria released the most dissolved phosphorus from organic phosphorus medium among the isolates,with a concentration of 1.88 mg·L-1 in 10 days.The bacteria with fastest short-term phosphorus release rate screened from the rhizosphere of Acorus calamus was identified as Pseudomonas sp.and the bacteria released the most dissolved phosphorus screened from the rhizosphere of reed was identified as Pseudomonas knackmussii.Different phosphate solubilizing bacteria had different effects on phosphorus content in water and phosphorus uptake by wetland plants.M24 and M25,which had the highest phosphate solubilizing capacity,were the most effective in removing phosphorus and promoting phosphorus uptake in plants.Phosphorus uptake by plants is mainly reflected by the growth of leaves and the increase of phosphorus content.The removal rate of total phosphorus in water increased with the raise of amount of phosphate solubilizing bacteria seeded on the rhizosphere of the plants,and the increase of phosphorus content in each part of the plant was more obvious.The p H variation was small during the incubation,which was ranged from 6.7~ 7.1.This study provides important basic data and conclusions for the use of highly effective phosphate solubilizing bacteria to enhance plant absorption of phosphorus and improve the phosphorus removal efficiency of wetlands.更多还原