【作者】 张丽娜；

【导师】 陈学林； 王桔红；

【作者基本信息】 西北师范大学 ， 植物学， 2017， 硕士

【摘要】 外来植物的入侵能够引起入侵地土壤微生物群落结构、理化性质及酶活性的变化,这种改变反过来也会影响入侵植物的生长及入侵植物与当地植物的竞争,这种新的入侵机制叫土壤微生物学互作机制。外来入侵植物与入侵地土壤微生物群落间的互作与反馈已成为研究外来植物入侵机制的重要内容和国际研究热点。本实验通过野外取样和温室盆栽实验从地上地下生态学角度对外来植物的入侵机制进行探究,旨在为有效预防和控制外来入侵植物、维持生态系统的稳定提供信息。主要结果如下:1外来植物入侵后对其根际土壤微生物的影响1)微生物可培养结果显示:随着植物入侵程度的加深,土壤中细菌和真菌数量显著增加,而放线菌数量却有所减少,可见红毛草入侵可能会促进土壤真菌生长而抑制放线菌生长。磷脂脂肪酸(PLFA)分析结果表明:PLFA标记为细菌的有24种,放线菌4种,真菌4种,原生动物1种。随着红毛草入侵程度的增加,根际土壤中细菌、真菌、原生动物以及PLFAs的相对总含量均呈现逐渐增加的趋势;细菌含量在各样地土壤中均占主导地位,随着红毛草的入侵,细菌、真菌的含量分别增加了 11.34%、19.60%;与未入侵地的对照组结果相比,红毛草重度入侵地根际土壤微生物中的丛枝菌根真菌相对含量增加了 29.80%,伯克霍尔德菌增加了 18.25%,嗜热解氢杆菌增加了 11.57%。三种不同入侵程度红毛草根际土壤中微生物多样性水平均有一定的差异。2)随着红毛草入侵程度的加重,土壤全氮、碱解氮、速效钾含量都有所提高。其中,全氮提高了 22.16%,碱解氮提高了 70.51%,速效钾提高了 2.7%,而速效磷含量基本无差异;土壤pH(F=62.647,P<0.01)以及含水量都有极显著的差异,与红毛草非入侵地土壤相比,重度入侵土壤pH增加了 15.09%,含水量(F= 46.317,P<0.01)增加了 32.95%。3)与红毛草未入侵地土壤相比,红毛草大量入侵后其轻度入侵区和重度入侵区土壤蔗糖酶分别增加了 51.55%和73.46%,脲酶活性分别增加了 12.80%和68.60%,过氧化氢酶活性分别减小了 22.5%和59.33%,而纤维素酶活性变化较不显著。4)土壤中细菌、真菌、放线菌和原生动物含量与土壤蔗糖酶和脲酶活性、pH、含水量均呈正相关,与过氧化氢酶活性呈现负相关;真菌、原生动物含量与纤维素酶活性呈正相关,细菌、放线菌与纤维素酶呈负相关。红毛草的定居能够改变土壤微生物群落结构、酶的活性以及土壤理化性质。2盆栽实验结果在杀真菌、杀细菌以及高温高压湿热灭菌和未处理的南美蟛蜞菊重度入侵土壤中,三种植物生长情况均存在较大差异。尤其是在高温高压湿热灭菌土壤中南美蟛蜞菊的生长受到显著抑制,与未处理土壤中的生长情况相比,株高降低了17.59%,叶片数降低了 38.10%,生物量降低了 56.00%,电子传递速率变化不明显。另外,在杀真菌土壤和杀细菌土壤中金腰箭的生长也受到显著抑制。与未处理土壤中的生长情况相比较,杀真菌土壤中的金腰箭株高降低最多,为42.28%,叶片数降低了 38.89%,生物量降低了 16.99%,电子传递速率变化不明显;在杀细菌土壤中其株高降低了 36.64%,叶片数降低最多,为38.89%,生物量降低了33.67%,电子传递速率升高了 11.11%。由此可见,不含微生物的土壤对南美蟛蜞菊生长有较强抑制作用,不含真菌和细菌的土壤对金腰箭的生长有明显抑制作用。南美蟛蜞菊重度入侵土壤不仅适合南美蟛蜞菊的生长,也适合金腰箭的生长,对狗肝菜影响不大。3竞争实验表明:土壤灭菌和添加杀真菌剂后入侵植物南美蟛蜞菊与两种伴生种的相对竞争优势度都有所下降。其中,与未灭菌的对照组相比,南美蟛蜞菊和狗肝菜混种时湿热灭菌土壤中的相对竞争优势度从65.65%降到50.58%,南美蟛蜞菊和金腰箭混种时湿热灭菌土壤中的相对竞争优势度从53.87%降到40.92%,说明入侵植物南美蟛蜞菊与其伴生植物竞争生长时部分微生物的促进作用较明显。研究结果还显示,南美膨蜞菊在四种处理土壤中的株高及生物量均表现为单种大于混种,说明伴生种狗肝菜和金腰箭抑制了南美蟛蜞菊的生长。本研究进一步证实土壤部分微生物类群有利于促进南美蟛蜞菊的竞争性扩张。更多还原

【Abstract】 The invasion of exotic plants can cause the microbial community structure of soil intrusion,physicochemical properties and enzyme activity change,this change in turn will affect the growth of plants and the invasion of invasive plants and native plants competition,invasion of this new mechanism called the interaction mechanism of soil microbiology.Invasive plant and soil microbial community between the intrusion the interaction and feedback mechanism of exotic plant invasion has become a research important content and the international research focus.This study from the angle of ecology underground alien plant invasion mechanism through field sampling and greenhouse pot experiment to explore,for the effective prevention and control of alien invasive plants,to maintain the stability of the ecosystem to provide information.The main results are as follows:1 Effects of exotic plant invasion on Rhizosphere Soil Microbes1)Microbial culture results display.There were 33 PLFA biomarkers in studied soil plots,including PLFA marker 24 bacteria species,four actinobacterias,four fungus and one protozoa;The invasion of R.repens may have greatly changed the microbial community structure in soil.With the increasing of invasion R.repens,the relatively contents of bacteria,fungi,protozoa,and total PLFAs showed a trend of increasing.Meanwhile,compared with the non-invasive soil,content of some functional microorganism in soil with strong invasion,in which the content of Abuscular mycorrhizal fungi increased by 29.80%,that of Burkholderia and Hydrogenobacter increased by 18.25%and 11.57%,respectively,indicating that these functional microorganisms may play an important role on the invasion of R.repens.In addition,Shannon-wiener index and Margalef index displayed an increasing trend with increasing of invasion,and the Pielou index showed a decreasing trend.2)With the red hair grass invasion degree increase,soil total nitrogen,available nitrogen,available potassium content was increased.The total nitrogen increased 22.16%,nitrogen increased 70.51%,available potassium increased by 2.7%,while the available phosphorus content had no difference between soil;pH(P<0.01)and the water there are very significant differences,compared with the red hair Caofei invaded soil,heavily invaded soil pH increased by 15.09%,water content(F = 46.317,P<0.01)increased by 32.95%.3)With the colonization and invasion of R.repens,the content of microorganism in soil significantly increased,in which the relative content of bacteria were increased by 11.34%,fungi and protozoa increased by 19.60%and 13.95%,respectively.Compared with the non-invaded soil,the invertase activity in soil with mold invasive and strong invasive increased by 51.55%and 73.46%,urease activity increased by 12.80%and 68.60%respectively,however,catalase activity decreased by 22.5%and 59.33%,and cellulase activity had no or less change.4)There was a significant positive correlation between the content of bacteria,fungi actinobacteria,protozoa and the invertase,urease activities,but a negative correlation with catalase activity.In addition,there was a significant positive correlation between the fungi,protozoa and cellulase activity,and a negative correlation between bacteria,actinobacteria and cellulase activity.The settlement of R.repens could change the soil microbial community structure,enzyme activity and soil physical and chemical properties.2 Greenhouse pot experiment shows:The experiment indicated that the growth of the three plants described above was different in disparate soil.The strongest growth inhibition is W.trilobata in sterilization soil.Compared with the growth of plants in untreated soil,the plant height was decreased by 17.59%,the number of leaves decreased by 38.10%,biomass was reduced by 56.00%.The growth inhibition of S.nodiflora was the greatest in anti-fungal soil.Compared with the plant in untreated soil,the height,the number of leaves,biomass,the electron transfer rate of S.nodiflora was decreased by 42.28%,38.89%,16.99%,7.41%.The growth inhibition of S.nodiflora was also the greatest in anti-bacteria soil,compared with the growth in untreated soil,the plant height was decreased by 36.64%,the number of leaves was decreased by 38.89%,biomass was reduced by 33.67%,the electron transport rate increased by 11.11%.The soil without microbes has a strong inhibitory effect on the growth of W.trilobata.The growth of fungi and bacteria in the soil of S.nodiflora had obvious inhibitory effects.The soil invaded by W.trilobata is not only suitable for W.trilobata’s growth,but also for its companion S.nodiflora’s growth.However,it has little effect on the D.chinensis.3 Competition experiments show:The relative competitive advantage of moist heat sterilization soil decreased from 65.65%to 50.58%when W.trilobata and D.chinensis mixed planting.The relative competitive advantage of moist heat sterilization soil decreased from 53.87%to 40.92%when W.trilobata and S.nodiflora mixed.The promoting effect of microorganism is obvious when invasive plant W.trilobata associated plant competition growth.The results also show that W.trilobata in four kinds of soil in height and biomass were a single value is higher than the mixed planting.That kind of associated(D.chinensis and S.nodiflora)inhibition of W.trilobata growth.This study further confirmed that the soil microbial community is conducive to promoting competition with W.trilobata.更多还原