黑麦草-内生真菌共生体对磷缺乏的生理生态反应

选取感染和未感染的黑麦草为材料,在田间盆栽条件下研究内生真菌感染对宿主植物抵抗磷胁迫方面的贡献。结果表明,土壤中缺磷或内生真菌感染对黑麦草地上部生长的影响不显著,但内生真菌感染对植株地下部生长和生理指标有明显影响。缺磷条件下,内生真菌感染有助于黑麦草地下部分的生长,表现在根系总长度更长,生物量更大;同时根中酚类物质和有机酸的含量也显著高于未感染植株,但因酚类物质和有机酸总量增加的同时并未伴随着二者浓度的增加,由此推测,内生真菌在改变宿主黑麦草根系代谢活动方面的贡献有限。此外,内生真菌感染显著提高了宿主植物的磷利用效率,这可能和缺磷条件下内生真菌感染植株具有更高的酸性磷酸酶活性有关。     

渗透胁迫下内生真菌感染对黑麦草幼苗生长的影响

以含有内生真菌的黑麦草(Lolium perenne L．)种子为材料,采用4C冰箱内和20℃光照培养箱内保存18个月的方式分别构建内生真菌感染(EI)和内生真菌非感染(EF)的黑麦草种群,通过比较EI和EF种群在正常条件下(对照)和渗透胁迫条件下种子发芽、幼苗生长等方面的差异,探讨内生真菌对其宿主植物的直接和间接影响。结果表明：在对照和胁迫条件下,E1种子的发芽势均明显高于EF种子,而只在重度渗透胁迫下,E1种子的发芽率才显著高于EF种子。对于黑麦草幼苗而言,渗透胁迫下内生真菌对宿主植物的地上部分和地下部分均有增益作用,最终表现为E1种群的总生物量显著高于EF种群,其中对地上部分的促进作用表现为内生真菌的存在不仅提高了宿主叶片的延伸速率、使EI叶片比EF叶片更长、叶面积更大,而且在重度胁迫下,E1种群的分蘖数也显著高于EF种群;对地下部分的促进作用表现为EI种群的根系总长度和根干重均高于EF种群。     

不同pH砖红壤浸提液和内生真菌对黑麦草幼苗生长生理的影响

以带内生真菌(E+)和不带内生真菌(E-)的多年生黑麦草(Lolium perenne)种子为材料,采用室内种子萌发实验,分析多年生黑麦草在不同pH(4.47~6.12)砖红壤浸提液中种子萌发、幼苗形态指标及生理指标的变化,探讨内生真菌对酸性环境中多年生黑麦草幼苗生长和生理特性的影响。结果表明:(1)在相同带菌情况下(内生真菌侵染E+或未浸染E-),随着砖红壤浸提液pH值的降低(浸提液酸性的增强),E+和E-种子发芽率、发芽势、发芽指数、活力指数、胚芽长、胚根长、胚芽鲜重和胚芽干重均表现为逐渐下降的趋势,且5个砖红壤浸提液处理均显著低于相应对照(CK,pH 6.12);幼苗脯氨酸含量、超氧化物歧化酶活性、过氧化物酶活性和丙二醛含量呈上升趋势,且5个砖红壤浸提液处理均显著高于相应CK。(2)除CK外,在相同pH砖红壤浸提液处理下,内生真菌侵染显著提高了多年黑麦草的发芽率、胚芽长、鲜重和干重等形态指标及脯氨酸含量和超氧化物歧化酶活性,却显著降低了过氧化物酶活性和丙二醛含量;在砖红壤浸提液pH为4.47~6.12时,E+萌发种子胚根长与E-之间无显著差异。研究发现,不同pH砖红壤浸提液对E+和E-种子萌发、生长和生理有一定的影响,内生真菌的侵染可促进宿主植物的生长,同时对砖红壤浸提液pH值具有较宽的适应范围,可将多年生黑麦草内生真菌共生体应用于酸性土壤改良。     

内生真菌侵染对黑麦草种子萌发、幼苗生长及渗透胁迫抗性的影响

以含有内生真菌的黑麦草(Lolium perenne L.)种子为材料,采用4 ℃冰箱内和20 ℃培养箱内保存18个月的方式分别构建内生真菌侵染（EI）和内生真菌非侵染（EF）的黑麦草种群,通过比较EI和EF种群在正常条件下（对照）和渗透胁迫条件下种子发芽、幼苗生长等方面的差异,探讨内生真菌对其宿主植物的直接和间接影响。结果表明：在对照和胁迫条件下,EI种子的发芽势及发芽率均明显高于EF种子,而在重度胁迫下EI植株的叶延伸速率、根系总长度高于EF植株。内生真菌对宿主植物分蘖数和生物量的变化没有促进作用,但     

内生真菌侵染对黑麦草种子萌发、幼苗生长及渗透胁迫抗性的影响

 以含有内生真菌的黑麦草(Lolium perenne L.)种子为材料,采用4 ℃冰箱内和20 ℃培养箱内保存18个月的方式分别构建内生真菌侵染（EI）和内生真菌非侵染（EF）的黑麦草种群,通过比较EI和EF种群在正常条件下（对照）和渗透胁迫条件下种子发芽、幼苗生长等方面的差异,探讨内生真菌对其宿主植物的直接和间接影响。结果表明：在对照和胁迫条件下,EI种子的发芽势及发芽率均明显高于EF种子,而在重度胁迫下EI植株的叶延伸速率、根系总长度高于EF植株。内生真菌对宿主植物分蘖数和生物量的变化没有促进作用,但     

氧化石墨烯对黑麦草种子内生真菌群落结构和多样性的影响

为了探究氧化石墨烯(GO)对黑麦草种子内生真菌群落结构和多样性的影响,将黑麦草种子在0.4%、0.8%和1.2%水平的GO溶液中胁迫4 d,采用高通量测序技术,分析GO胁迫下黑麦草种子内生真菌群落组成和多样性的变化。结果显示,4个样本所有样品共分离获得303种真菌,归属于10门39纲84目160科240属。在门分类水平上,子囊菌门(Ascomycota)和担子菌门(Basidiomycota)是主要的内生真菌类群;在属分类水平上,各处理的共有优势菌属为链格孢属(Alternaria)。不同GO处理黑麦草种子内生真菌群落结构存在差异,随着GO浓度的增加,子囊菌门的丰度出现下降,0.8%和1.2%GO处理较对照分别显著降低了19%和20%(P<0.05);所有GO处理的担子菌门丰度均显著高于对照(P<0.05);1.2%处理链格孢属的丰度较对照显著降低了37.36%。与对照相比,1.2%GO 处理内生真菌的丰富度和多样性显著增加,ACE、Chao1和Shannon指数分别增加了123.5%、127.4%和117.5%(P<0.05)。主坐标分析(PCoA)分析表明,1.2%GO处理内生真菌群落结构与其他处理有较大差异;线性判别分析(LEfSe)分析发现, 各处理差异指示种明显不同。可见,GO改变了黑麦草种子内生真菌群落的组成和多样性,尤其是高浓度处理(1.2%)。研究可为碳纳米材料暴露对共生物种的潜在影响研究提供参考。     

水分胁迫下内生真菌感染对黑麦草叶内游离脯氨酸和脱落酸含量的影响

以黑麦草为实验对象,研究了干旱胁迫条件下内生真菌感染对植株叶片含水量和叶内游离脯氨酸含量的影响,同时对渗透胁迫条件下植株叶内ABA含量的变化进行了分析。结果表明：①内生真菌的感染有助于使叶片保持较高的含水量;②在两种形式的水分胁迫下,。前期至中期高感染种群的叶片游离脯氨酸含量低于感染种群,而在末期则有高出低感染种群的趋势;③内生真菌感染对黑麦草叶内ABA累积的正效应只发生在轻度渗透胁迫下的较短时间范围内。     

内生真菌感染对干旱胁迫下黑麦草生长的影响

 内生真菌是生活在健康植物的茎叶内,形成不明显感染的一类真菌。以黑麦草（Lolium perenne L.）为实验材料,研究在不同强度的干旱胁迫下内生真菌（Neotyphodium lolii）侵染对其叶片延伸生长、分蘖数和生物量的影响。结果表明,与非感染种群相比,内生真菌感染对黑麦草叶片延伸速率无明显促进作用;内生真菌感染种群具有明显较多的分蘖数;在重度胁迫并经过恢复期后,内生真菌感染种群具有较高的根冠比。因而内生真菌可能通过提高植物的分蘖能力和促进有机物向根系的分配来促进宿主植物的营养生长并提高其抗旱性     

植物-内生真菌共生体对昆虫种群的影响

植物内生真菌与植食性昆虫共用寄主植物作为食物、能量来源及栖息场所,三者之间的互作关系复杂多变,在生物种群控制、生物进化和植物生产中发挥重要作用.从植物-内生真菌共生体、内生真菌对植食性昆虫与多级营养层的影响,及内生真菌抗虫代谢产物等方面概括了内生真菌-植物-昆虫相互关系的研究进展,建议将植物内生真菌纳入植物生态学、昆虫生态学和作物病虫害控制的范畴内.     

渗透胁迫和缺磷对小麦幼苗生长的影响

水培条件下缺磷小麦幼苗的叶片含水量和叶绿素含量显著降低,丙二醛含量增加,小麦幼苗生长受抑,地上部分生长受到的影响大于根系,上述指标的变化幅度还与缺磷程度呈正相关,且不耐低磷品种中国春大于耐低磷品种烟中144。在相同条件下,渗透胁迫和缺磷两者表现出胁迫加剧的现象。     

高羊茅和多年生黑麦草内生真菌的分子检测

根据GenBank上报道的内生真菌Neotyphodium coenophialum和N.lolii的Nc25基因序列,设计了2对特异性引物FM1/R1和F3/R652,建立了一套适合于从高羊茅和多年生黑麦草种子中检测内生真菌N.coenophialum和N.lolii的常规PCR和巢式PCR方法。     

多年生黑麦草的逆境生理研究进展

在研究和借鉴国内外最新研究成果的基础上,系统论述和报道了多年生黑麦草在水分、温度以及重金属等逆境胁迫下的生理变化,展望了多年生黑麦草在逆境生理方面的研究趋势,指出多年生黑麦草的抗性机理以及相关分子生物学方面的研究将成为未来研究的重点和热点,为今后深入开展多年生黑麦草的研究和利用提供科学依据。     

Influence of Nitrogen Fertilizer and Endophyte Infection on Ecophysiological Parameters and Mineral Element Content of Perennial Ryegrass

An expedment was designed to determine the effect of the fungal endophyte Neotyphodium lolii on the growth, physiological parameters and mineral element content of perennial ryegrass (Lolium perennel L.), when growing at two N supply levels. Endophyfe infection had a significant positive effect on both shoot and root growth of ryegrass, but this difference was only significant in the high N supply treatment. At high N supply, endophyte-infected (EI) plants accumulated more soluble sugar in the sheath and the root than endophyte-free (EF) plants. Endophyte infection affected mineral element concentrations In the root more than in the shoot. We found a significant effect of endophyte infection on B, Mn and Mg in the root, but significant effect was only found on B in the shoot. EI plants tended to accumulate less B in the shoot at both N levels, but accumulated more B, Mn and Mg in the root at low N levels. The difference of growth parameters in different periods was significant. The content of soluble sugar and crude protein in the sheath were also dependent on the growth stages of both EI and EF plants.     

低磷胁迫对水稻苗期侧根生长及养分吸收的影响

用蛭石与石英砂作为混合培养介质研究了低磷胁迫对水稻（Oryza sativa L.)苗期侧根发生发育的影响及其与磷吸收的相关关系。结果表明：低磷对水稻的侧根发生发育具有明显的诱导作用及基因型差异。相关性分析表明：单位侧根长度的增加与单位根表面积的增大极显相关,而单位侧根数量的增多与单位根表面积的增大无显的相关性。表明单位根表面积的增加主要来自于单位侧根的伸长。侧根参数与磷含量的相关性分析表明：低磷条件下,侧根总长度和侧根数量都与植株磷含量存在显的正相关,根系总表面积与磷含量存在极显的正相关。表明在低磷条件下,侧根的发生发育对水稻的磷吸收具有重要的作用。根系和地上部的可溶性糖含量分析表明;低磷胁迫改变了同化物在地上部和根系的分配。生物量测定表明：低磷胁迫显增大了植株的根冠比。     

Effect of Phosphorus Deficiency Stress on Rice Lateral Root Growth and Nutrient Absorption

Six rice (Oryza sativa L.) genotypes with different performances under phosphorus (P) deficiency stress were tested in mixed growth medium of vermiculite and sand under different conditions of P supply to evaluate the effects of P deficiency stress on lateral root growth and the relations between lateral root growth induced by P deficiency and P absorption. The results showed that elongation and development of lateral root were induced by P deficiency. There was significant genotypic variation in lateral root growth in response to P deficiency. A significant positive correlation was observed between the increase of lateral root length per cm of nodal root and the increase of root surface area per cm of nodal root (RSAP), while no significant correlation was observed between the increase of lateral root number per cm of nodal root and the increase of RSAP. The result suggested that the increase of root surface area under P deficiency condition could be mainly attributable to the increase of lateral root length induced. P uptake was significantly positively correlated with the total root surface area and positively correlated with the total lateral root length and the total lateral root number under P deficiency, which implied that elongation and development of lateral root were important to the ability of P uptake from growth medium where P supply was poor. Analysis of soluble sugar content indicated that P deficiency stress changed the distribution of carbohydrate between roots and shoots.     

Development of a genomic microsatellite library in perennial ryegrass (Lolium perenne) and its use in trait mapping

Background and Aims: Perennial ryegrass (Lolium perenne) is one of the key forageand amenity grasses throughout the world. In the UK it accountsfor 70 % of all agricultural land use with an estimated farmgate value of £6 billion per annum. However, in termsof the genetic resources available, L. perenne has lagged behindother major crops in Poaceae. The aim of this project was thereforethe construction of a microsatellite-enriched genomic libraryfor L. perenne to increase the number of genetic markers availablefor both marker-assisted selection in breeding programmes andgene isolation. Methods: Primers for 229 non-redundant microsatellite markers were designedand used to screen two L. perenne genotypes, one amenity andone forage. Of the 229 microsatellites, 95 were found to showpolymorphism between amenity and forage genotypes. A selectionof microsatellite primers was selected from these 95 and usedto screen two mapping populations derived from intercrossingand backcrossing the two forage and amenity grass genotypes. Key Results and Conclusions: The utility of the resulting genetic maps for analysis of thegenetic control of target traits was demonstrated by the mappingof genes associated with heading date to linkage groups 4 and7.     

Phosphorus nutrition-mediated effects of arbuscular mycorrhiza on leaf morphology and carbon allocation in perennial ryegrass

The aim of this work was to disentangle phosphorus status-dependent and -independent effects of arbuscular mycorrhizal fungus (AMF) on leaf morphology and carbon allocation in perennial ryegrass (Lolium perenne). To this end, we assessed the P-response function of morphological components in mycorrhizal and nonmycorrhizal plants of similar size. AMF (Glomus hoi) stimulated relative P-uptake rate, decreased leaf mass per area (LMA), and increased shoot mass ratio at low P supply. Lower LMA was caused by both decreased tissue density and thickness. Variation in tissue density was almost entirely caused by variations in soluble C, while that in thickness involved structural changes. All effects of AMF were indistinguishable from those mediated by increases in relative P-uptake rate through higher P-supply rates. Thus the relationships between relative P-uptake rate, leaf morphology and C allocation were identical in mycorrhizal and nonmycorrhizal plants. No evidence was found for AMF effects not mediated by changes in plant P status.