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狐尾藻腐解释放胡敏酸的特性及对沉水植物生长的影响
论文作者:童鞋论文网  论文来源:www.txlunwenw.com  发布时间:2019/9/11 8:31:25  

摘要:目前,在全球性生态问题中,湖泊富营养化因其会导致水生植被大规模衰退而备受瞩目,恢复沉水植被是当前生态修复工程中的重要内容。沉水植物腐解,残体会通过微生物分解缩合产生胡敏酸(HA),HA可以刺激植物激素的合成,因而探究沉水植物腐解释放 HA的特性及其对沉水植物生长的影响具有重要意义。本论文选择典型沉水植物狐尾藻、菹草为实验对象,分析狐尾藻在不同营养底泥腐解过程中HA的变化,并深入研究HA对狐尾藻和菹草这两种沉水植物生长以及生长过程中底泥细菌群落多样性的变化。研究成果如下:

(1)狐尾藻在不同营养底泥腐解过程中胡敏酸的变化研究

通过采用平行因子分析法,结合紫外吸收光谱技术、三维荧光光谱以及傅里叶变换红外光谱技术,研究狐尾藻在低、中、高营养底泥腐解过程中HA的变化,进一步阐释不同营养底泥对狐尾藻腐解的影响机制。结果表明,底泥营养水平越高,狐尾藻腐解得越快(P<0.05);荧光鉴别出不同营养底泥HA都含有1种类蛋白质组分C2和2种类富里酸组分C1、C3;各处理组的HA红外图谱在不同时间内相似,表明不同营养底泥腐解条件不同时间提取的HA官能团相似。

(2)胡敏酸对沉水植物生长及生理的影响研究

以原沉积物和分别添加2 g/kg、5g/kg、10 g/kg HA的沉积物作为底质培育沉水植物,采用室内模拟试验研究了HA对狐尾藻和菹草生长及生理的影响。结果显示,在狐尾藻和菹草生长初期,HA的添加会在一定程度上抑制植物的生长,但在整个培养期,与未添加HA组相比,5 g/ kg HA的添加对狐尾藻和菹草的生长有一定的促进,而10 g/kg HA的加入使得狐尾藻和菹草根系受到损伤,不利于其生长,与菹草相比,狐尾藻在高浓度HA胁迫条件下,光合作用能力更强;2 g/kg、5 g/kg HA添加条件下,超氧化物歧化酶(SOD)活性持续升高,10 g/kg胡敏酸添加组SOD活性先升高后降低,表明高浓度HA造成的环境胁迫对抗氧化酶系统形成了一定的伤害,使得丙二醛(MDA)有所增加,狐尾藻和菹草比原沉积物组分别增加了22.75 %、121.10 %。

(3)胡敏酸对底泥细菌群落结构的影响研究

在狐尾藻和菹草生长期间,高HA添加组(10g/kg)特有细菌种类较多,由于占比很小,丰富度极低,因而在门、科水平上优势菌种丰度分析结果中未能体现。狐尾藻生长(7-56 d)发现,4个处理组底泥中均以绿弯菌门(Chloroflexi)和变形菌门(Proteobacteria)居多,与第0 d相比厚壁菌门(Firmicutes)和放线菌门(Actinobacteria)的丰度明显降低,菹草生长(7-56 d)与第0 d相比,Firmicutes丰度明显降低,Proteobacteria丰度有所增加;主成分分析结果显示,在整个狐尾藻和菹草生长培养期,不同HA添加量对底泥细菌群落结构没有显著影响,这与门、科水平上细菌群落组成以及Alpha多样性分析结果一致。

At present, in global ecoligical issues,eutrophication of lacks is attracting attention because of its large-scaledecline in aquatic vegetation. Restoration of submerged vegetation is animportant part of the current ecological restoration project. Submergedmacrophytes themselves are decomposed and the residues pass throughmicroorganisms. Decomposition and condensation produce humic acid, humic acidcan stimulate the synthesis of plant hormones. Therefore, it is of greatsignificance to study the characteristics of humic acid macrophytesdecomposition release and its effect on the growth of submerged macrophytes. Inthis study, we selected  typicalsubmerged macrophytes (Myriophyllum spicatum and Potamogeton crispus) asexperimental subjects. Studying the characteristics of humic acid Myriophyllumspicatum decomposition release under different nutrient sediment conditions andin-depth studying effects of humic acid on the growth and bacterial communitydiversity of Myriophyllum spicatum and Potamogeton crispus. The researchresults are as follows:

(1)The changes ofhumic acid in the process of decomposition of Myriophyllum spicatum

By using parallel factor analysis method,combined with UV absorption spectroscopy, three-dimensional fluorescencespectroscopy and Fourier transform infrared spectroscopy, studying the changeof humic acid in low, medium and high nutrient sediments revealed fromMyriophyllum spicatum decomposition and in-depth understanding of the influencemechanism of different nutrient sediments on the decomposing of Myriophyllumspicatum. The results showed that the higher was the nutrient level of thesediment, the faster was the decomposing of the foxtail algae (P<0.05).Humic acid of different nutrient sediments were identified by fluorescencecontaining one kind of protein component C2 and two kinds of fulvic acidcomponents C1, C3; Humic acid extracted from different nutrient sedimentsanalyzed by infrared spectra was similar at different times, indicating that HAextracted at different decomposition conditions and times contains similar functionalgroups.

(2)Effects of humicacid on the growth and physiology of submerged macrophytes

 With the sediment applied with 0 g/kg, 2 g/kg, 5 g/kg, 10 g/kg humicacid as the substrate, a simulating experiment was conducted to study theimpacts of humic acid on the growth and physiology of Myriophyllum spicatum andPotamogeton crispus. The results showed that the growth of submerged plants wasinhibited by adding humic acid into sediment at early stage. Comparing withthose in control, the growth of Myriophyllum spicatum and Potamogeton crispusat 5 g/kg addition treatment were promoted in the whole process, 10 g/kgaddition treatment caused damage to the roots of Myriophyllum spicatum andPotamogeton crispus, which were not conducive to the growth of Myriophyllumspicatum and Potamogeton crispus. Compared with Potamogeton crispus,Myriophyllum spicatum can show stronger photosynthesis ability under the stressof high concentration of humic acid. At the 2 g/kg and 5 g/kg additiontreatments, SOD activities increased all the time. At the 10g/kg additiontreatment, the activities of SOD was increased firstly and decreased then. Itindicated that the environmental stress caused by high concentration of humicacid formed certain damage to the oxidase system, which increased themalondialdehyde (MDA) of Myriophyllum spicatum and Potamogeton crispus andincreased by 22.75% and 121.10% compared with the original sediment group.

(3)Effect of humicacid on bacterial community structure of sediment

During the growth of Myriophyllum spicatumand Potamogeton crispus, the high-HA addition group (10 g/kg) had more endemicbacteria species, and because of the small proportion and low enrichment, theabundance analysis of dominant species at the level of the door and family wasanalyzed.

关键词:水体富营养;狐尾藻腐解;胡敏酸;沉水植物生长;细菌群落多样性

water eutrophication; Myriophyllum spicatumdecomposition; humic acid;submerged macrophyte growth;bacteria community diversity

上一篇:超声-镧改性沸石对富营养水体同步脱氮除磷的研究     下一篇:无回流A1/O1/A2/O2+潜流式湿地处理农村生活污水效能研究
 
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