【作者】 方爱国；

【导师】 李春杰；

【作者基本信息】 兰州大学 ， 植物病理学， 2013， 硕士

【摘要】 禾草内生真菌(Neotyphodium/Epichloe)和丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)是两类最主要的草地植物共生真菌,其与草地植物的共生,可增加宿主植物抗旱等抗逆特性,促进宿主植物生长。野大麦(Hordeum brevisubulatum)是一种生长于甘肃临泽天然草地的耐盐碱优良牧草。本论文分别以带内生真菌和AMF(M+E+)、只带AMF但不带内生真菌(M+E-),只带内生真菌但不带AMF(M-E+)和均不带内生真菌和AMF(M-E-)的野大麦为植物材料,通过研究在NaCl (0,200,400,600mmol/L)和P (0,0.05,2mmol/L)处理下禾草内生真菌和菌根菌对野大麦株高、分蘖、生物量及N、P含量等方面的影响,初步研究了在不同胁迫下内生真菌和菌根菌对宿主植物所起的作用,并寻找共生真菌-宿主植物-外界环境的动态平衡。获得了以下主要结果：1.正常条件下,内生真菌的存在可显著抑制丛枝菌根真菌的侵染(P＜0.05),抑制率为41.67%。内生真菌和菌根真菌均可显著增加野大麦的地上生物量和总生物量(P＜0.05),而菌根菌可显著增加野大麦的地下生物量(P＜0.05)。两种共生体结构共存时野大麦的N含量显著小于单个共生体的处理(P＜0.05)。只带菌根(M+E-)的野大麦P含量显著大于两种共生体结构共存时的野大麦P含量(P＜0.05),表明内生真菌的存在降低菌根菌对野大麦P的吸收和积累。2.盐胁迫条件下,两种真菌单独或共同存在均可增加野大麦地上、地下和总生物量。与不带菌处理(M-E-)相比,当NaCl浓度为200mmol/L时,内生真菌单独(M-E+)或两种真菌共存(M+E+)都能显著增加地上生物量(P<0.05),而菌根的存在(M+E+和M+E-)对地下生物量有显著促进作用(P＜0.05)；NaCl浓度为400mmol/L时,带内生真菌和AM真菌的处理显著提高了野大麦的生物量(P＜0.05),但三个处理之间差异不显著(P＞0.05)；当NaCl浓度达到600mmol/L时,各菌处理之间生物量则无显著性差异(P＞0.05)。随着NaCl胁迫浓度从(0-600mmol/L)的增加,野大麦各处理地上全氮含量先增加后降低、地下N和P均呈现下降的趋势。在200mmol/LNaCl时,内生真菌可显著促进地上N的吸收(P<0.05);AMF可显著促进地上和地下P的吸收(P＜0.05)；两种菌共存时促进作用则不明显。3.高磷(Hp,2mmol/L KH2PO4)、低磷(Lp,0.05mmol/L KH2PO4)和无磷(Op)水平下,与不带菌的处理(M-E-)相比,M-E+显著提高了野大麦的株高和分蘖P＜0.05)；M+E+处理的地上、地下生物量显著大于其它水平的处理(P＜0.05)。在Op条件下,有AM真菌的处理M+E+和M+E-地下生物量显著高于其它处理(P＜0.05)。在Lp水平下,带内生真菌的处理M-E+和带AM真菌的处理M+E-对野大麦的氮、磷的累积有显著的促进作用(P＜0.05)。更多还原

【Abstract】 Neotyphodium/Epichloe endophytes not only confer enhanced fitness, but also have the positive effect on stress tolerance and plant growth of the host grass. Arbuscular Mycorrhizal Fungi (AMF) can improve the mineral nutrition especially P uptake and storage in the plants. Both symbionts of Neotyphodium endophyte and AMF in wild barley (Hordeum brevisubulatum) were studied under different conditions of normal, salt (0,200,400,600mmol/L NaCl) and phosphorus (0,0.05,2mmol/L P) stresses, with four treatments of both endophyte infected (M+) and AMF infected (M+)(M+E+), only AMF (M+E-), only endophyte infected (M-E+) and non fungi (M-E-). The main results were summarized as followings:1. Under the normal conditions, AMF infection and colonization in H. brevisubulatum were significantly inhibited by the Neotyphodium endophyte (P<0.05), the inhibition rate was41.67%. The above-ground and total biomass of the grass were significantly increased by both grass endophytes and AMF, while the root biomass was significantly increased by AMF (P＜0.05), but not endophyte. The accumulation of nitrogen (N) and phosphrus (P) in host grass showed that the contents of total N in the treatments with only endophyte or AMF infected alone was significantly higher than those of with both fungi infected, respectively (P＜0.05). P absorption and accumulation caused by AMF were inhibited by the endophyte as well.2. Under the salt stress condition, the shoot biomass of the M+E+and M-E+treatments were increased significantly (P＜0.05), and the root and total biomass of the M+E+, M+E-and M-E+treatments were significantly (P＜0.05) promoted under200mmol/L NaCl solution..Under400mmol/L NaCl solution, both endophyte and AMF had positive promotion to its host plant (P＜0.05), however, there was no significantly diferencees among them under600mmol/L NaCl. With increasing of NaCl solution, the shoot N content in the plant increased then decreased, but root N and P decreased. But the content of N in root and P tended to be decresed. Under200mmol/L NaCl, endophyte could significantly increase absorption of shoot N (P＜0.05), AMF could significantly increase absorption of shoot and root P.. However, there was not significant promotion effect by endophyte and AMF co-existed.3. Under treatments of high P (2mmol/L KH2PO4, Hp), low P (0.05mmol/L KH2PO4, Lp) and non-P (0mmol/L KH2PO4, Op) conditions, compared with non-fungal treatment, only endophyte (M-E+) could significantly improve plant height and tiller numbers (P＜0.05), dual infection (M+E+) significantly increased shoot and root biomass of plant (P＜0.05). Under Op level, M+E+and M+E-had significantly more root biomass than those of under other treatments (P＜0.05). Under the Lp level, both M-E+and M+E-increased the content of N and P accumulation in host plants (P＜005).更多还原