内生真菌对苇状羊茅和多年生黑麦草影响的研究进展

综述了内生真菌的分类及其在宿主苇状羊茅Festuca arundinacea和多年生黑麦草Lolium perenne中的分布与传播方式,阐述了内生真菌对苇状羊茅和多年生黑麦草生长、抗生物(病虫害)和非生物胁迫(P胁迫和干旱胁迫等)、以及对其他草类的竞争他感作用的影响,并提出今后的研究方向.     

AM真菌与禾草内生真菌对黑麦草抗旱性的影响

通过温室盆栽试验,从植物生长、养分吸收和抗逆相关酶等方面探究了AM真菌与禾草内生真菌互作对黑麦草(Loliumperenne)抗旱性的影响,以期为充分利用两类微生物来提高植物抗逆性提供理论依据。本研究包括单独接种AM真菌、禾草内生真菌,AM真菌+禾草内生真菌以及无AM真菌和无禾草内生真菌4种处理,黑麦草分别由含有禾草内生真菌(E+)和不含禾草内生真菌(E-)种子建植获得。并于黑麦草生长38 d后,按照土壤最大持水量的15%、30%、45%和60%设置4个水分梯度,共16种处理。结果表明,接种AM真菌与禾草内生真菌显著促进了45%和60%土壤水分条件下黑麦草的生长,促进了其对N、P的吸收,增强了黑麦草体内过氧化物酶活性,降低了丙二醛浓度,表明本研究所用共生微生物仅在较为干旱条件下提高了植物的耐旱性。     

Evaluation of perennial ryegrass straw as a forage source for ruminants

Two experiments were conducted to evaluate perennial ryegrass straw as a forage source for ruminants. Experiment 1 evaluated digestion and physiological variables in steers offered perennial ryegrass straw containing increasing levels of ergot alkaloid, lolitrem B. Sixteen ruminally cannulated Angus x Hereford steers (231+/-2 kg BW) were blocked by weight and assigned randomly to one of four treatments. Steers were provided perennial ryegrass straw at 120% of the previous 5-d average intake. Before straw feeding, soybean meal was provided (0.1% BW; CP basis) to meet the estimated requirement for degradable intake protein. Low (L) and high (H) lolitrem B straws (<100 and 1,550 ppb, respectively; DM basis) were used to formulate treatment diets: 100% L; 67% L:33% H; 33% L:67% H; 100% H (DM basis). Intake and digestibility of DM and OM, and ruminal pH, total VFA, and NH3-N were not affected by increasing lolitrem B concentration. Ruminal indigestible ADF (IADF) fill increased linearly (P = 0.01) and IADF passage rate decreased linearly (P = 0.04) as lolitrem B increased. Experiment 2 evaluated performance and production by 72 Angus x Hereford cows (539+/-5 kg BW) consuming perennial ryegrass straw containing increasing lolitrem B during the last third of gestation. Cows were blocked by body condition score and randomly assigned to one of three treatments. Cows were provided perennial ryegrass straw ad libitum and supplemented with soybean meal (0.1% BW; CP basis) to meet the estimated requirement for degradable intake protein. Mixtures of a L and H lolitrem B straw (467 and 2,017 ppb, respectively) were used to formulate treatment diets: 100% L, 50% L:50% H, 100% H (DM basis). Thirteen of 24 cows on the 100% H treatment exhibited signs of ryegrass staggers and were removed from the study; nevertheless, lolitrem B concentration did not influence pre- or postcalving weight or body condition score change. These data suggest that feeding perennial ryegrass straw containing up to 1,550 ppb lolitrem B (DM basis) did not adversely affect nutrient digestion or physiological response variables in steers. However, providing straw with a lolitrem B concentration of approximately 2,000 ppb (DM basis) resulted in 54% of cows exhibiting signs of ryegrass staggers. These data suggest that blending straws with a high (>2,000 ppb) and low (<500 ppb) concentration of lolitrem B can be a successful management practice.     

Lolitrem B residue in fat tissues of cattle consuming endophyte-infected perennial ryegrass straw.

Lolitrems are neurotoxins found in endophyte-infected perennial ryegrass. Lolitrems, primarily lolitrem B, are the causative agents of ryegrass staggers in livestock. To guarantee the safety of meat produced from cattle consuming endophyte-infected perennial ryegrass, lolitrem B concentrations in tissues of Japanese Black cattle were determined using high-performance liquid chromatography. Lolitrem B was not detected in muscle, liver, kidney, or cerebrum of a Japanese Black cow with signs of ryegrass staggers. In contrast, perirenal fat contained 210 ppb lolitrem B. Three cows that received half as much perennial ryegrass straw as the cow with ryegrass staggers showed no clinical signs of ryegrass staggers. However, low concentrations of lolitrem B (less than 150 ppb) were detected in their fat tissue. These observations indicate that human exposure to the neurotoxic effect of lolitrem B through beef is unlikely. The amount of lolitrem B consumed by cattle can be estimated by the determination of lolitrem B in fat tissue.     

禾草内生真菌与2种AM真菌互作对黑麦草生长的影响

在温室盆栽条件下,以侵染内生真菌和未侵染内生真菌的黑麦草为材料,接种幼套球囊霉(Claroideoglomus etunicatum)和根内球囊霉(Rhizophagus intraradices)以及两种AM真菌的混合菌剂,通过比较单一及混合AM真菌和禾草内生真菌对黑麦草株高、根长、生物量、P含量、可溶性糖、可溶性蛋白以及光合指标等方面的差异,探究AM真菌与禾草内生真菌对黑麦草生长的影响。结果表明,接种幼套球囊霉、根内球囊霉和混合菌剂的黑麦草平均AM真菌侵染率分别为44.04%,34.13%和41.13%,禾草内生真菌降低AM真菌平均侵染率22.28%。接种AM真菌和侵染禾草内生真菌均提高了黑麦草形态和生理生化指标,且二者(尤其是幼套球囊霉与禾草内生真菌)共存时,黑麦草的形态和生理生化指标最高,与既不侵染禾草内生真菌也不接AM真菌的处理相比,幼套球囊霉与禾草内生真菌共同作用时总P含量、总生物量和净光和速率分别提高48.21%, 21.12%和73.53%,总可溶性糖和蛋白分别提高147.12%和24.27%。总体而言,AM真菌显著促进了植物地上、地下部分生长,而禾草内生真菌主要促进植物地上部分的生长。     

西藏青稞秸秆与多年生黑麦草混合青贮发酵品质的研究

本研究旨在将青稞秸秆与黑麦草以不同比例混合青贮,评价其发酵品质,筛选出适宜的混合比例。试验设青稞秸秆单独青贮(对照组)、80%青稞秸秆+20%多年生黑麦草混贮(L组)、60%青稞秸秆+40%多年生黑麦草混贮(M组)及40%青稞秸秆+60%多年生黑麦草混贮(H组)4个处理。青贮后第7,14和30天后打开青贮窖,测定青贮饲料发酵品质。结果表明,青稞秸秆与黑麦草混合青贮显著(P<0.05)提高了乳酸和水溶性碳水化合物含量,显著(P<0.05)降低了pH值和干物质含量,M和H组在乳酸产生的同时乙酸含量显著(P<0.05)提高,混贮组氨态氮/总氮略低于对照组(P>0.05),各组均显示较低的丙酸和丁酸含量。从秸秆利用最大化的角度出发,建议以40%黑麦草混合青贮较为适宜。     

Young perennial ryegrass staggers in a dairy herd

Ryegrass staggers was diagnosed in a group of young stock on a dairy farm in the Netherlands. The cattle were fed on ryegrass hay originating from a farm in the region. The typical clinical signs observed in this herd were difficulty in rising, hypermetria of especially the front legs, incoordination, and tremors of the head and neck muscles. The morbidity of the illness was about 80 percent and there was no mortality. Four weeks after withdrawal of the hay, the animals recovered completely. The diagnosis was confirmed by demonstrating high concentrations of Lolitrem-B (1.7 ppm) in the hay. This neurotoxin is usually produced by the endophyte Neotyphodium lolii with which ryegrass may be infected. This is the first case of ryegrass staggers in cows reported in the Netherlands since 1992.     

坪用多年生黑麦草在成都的引种适应性研究

研究了 16个多年生黑麦草草坪草新品种的引种适应性 ,结果表明 :16个黑麦草品种基本上均能适应成都地区 ,绿期达 36 5d;冬春季草坪质地较好 ,各项评分得分较高 ,但夏季表现枯草层多 ,草坪密度变稀 ;从总体表现来讲 ,Top hat、Barusa94 - 11、Pinnaele表现较其它品种优 ;从色泽上看 ,Top hat、Barusa94 - 11、J6 1PR2 76得分较高。     

多花黑麦草不同生长期营养价值评定

采用饲料常规分析方法,如范氏洗涤纤维和两级离体消化法对多花黑麦草不同生长时期的常规营养成分、范氏纤维和体外消化率进行测定。结果表明:多花黑麦草随着生育期的延长,粗蛋白,Ca和P含量以及体外消化率逐渐下降,范氏纤维指标逐渐升高。在抽穗期CP水平最高,Ca和P相对也较高,多花黑麦草刈割饲用的最佳时期是抽穗期。     

添加糖蜜和乳酸菌制剂对西藏青稞秸秆和多年生黑麦草混合青贮发酵品质的影响

为探究不同添加剂对青稞秸秆与多年生黑麦草(4∶6)混合青贮发酵品质的影响,试验设对照组(C)、乳酸菌制剂组(LAB)、糖蜜组(M)、乳酸菌制剂+糖蜜组(LAB+M)4个处理,青贮后第7, 24和45天打开,测定青贮发酵品质。结果表明,添加乳酸菌制剂加速了青贮早期乳酸发酵进程,但由于底物不足,青贮后期丁酸含量和氨态氮/总氮值有所升高;添加糖蜜补充了发酵底物,促进了乳酸发酵,显著(P<0.05)提高了乳酸含量,降低了pH值(P<0.05),从而有效地抑制了有害微生物的活性,减少了丙酸和丁酸的生成。乳酸菌制剂+糖蜜组与单独添加乳酸菌制剂组相比显著提高了青贮发酵品质, 但与单独添加糖蜜组相比差异不显著,表明发酵底物不足是限制青稞秸秆与多年生黑麦草混合青贮发酵品质的主要因素。     

添加糖蜜对青稞秸秆和多年生黑麦草混合青贮发酵品质及营养价值的影响

试验在青稞秸秆与多年生黑麦草以6∶4混合的基础上,添加3%,4%和5%的糖蜜,旨在进一步改善混合青贮发酵品质和营养价值,为西藏地区青稞秸秆青贮利用提供理论依据。结果显示,青贮前14天,糖蜜添加组乳酸含量快速增加,pH值迅速下降。对照组pH值未能降至4.2以下,而糖蜜添加组均在4.0左右,乳酸、水溶性碳水化合物含量和乳酸/乙酸显著高于(P<0.05)对照组,氨态氮/总氮均低于对照组,且添加3%糖蜜已达到优质青贮饲料标准。青贮第60天糖蜜添加组有较高的粗蛋白含量,较低的中性洗涤纤维和酸性洗涤纤维含量,各组体外降解率均高于青贮材料。综合考虑,在青稞秸秆和黑麦草以6∶4混合的基础上添加3%的糖蜜可获得优质青贮饲料。     

草坪型多年生黑麦草种子生产性能的研究

采用裂区试验设计,研究了施肥量和播利量及其组合对草坪型多年生黑麦草种子生产性能的影响。结果表明,施肥量处理间以Ｎ·Ｐ·Ｋ比例为８０：３０：３０的种子产量最高;播种量对多年生黑麦草结实性能的种子产量的影响差异不显,因此,在多年生黑麦草种子生产中采用低播种量较好,对种子生产性能而言,施肥量效应与播种量效应间彼此独立。     

木糖对多年生黑麦草愈伤组织生长的影响

木糖被认为是生物安全的选择试剂.为探讨木糖异构酶基因能否作为筛选标记在多年生黑麦草(Lolium perenne)遗传转化中运用.以成熟种子诱导的愈伤组织为外植体.研究木糖作为碳源对愈伤组织生长的影响,5周后观察结果.结果表明,在愈伤组织继代培养基(SM)中分别添加蔗糖、木糖以及不同配比蔗糖+木糖,愈伤组织生长状况不同...     

多年生黑麦草LpGCS基因克隆及其在烟草中的初步功能验证

本研究以多年生黑麦草‘高帽2号’叶片为试材,根据同源基因的CDS序列设计简并引物,采用RT-PCR和RACE技术,克隆了多年生黑麦草γ-谷氨酰基半胱氨酸合成酶基因LpGCS。该基因全长为1674 bp(GenBank登录号:KJ551844),具有完整的开放阅读框(ORF),共1125 bp;对其氨基酸序列特性、结构以及与其他8种同源基因氨基酸序列间的同源性进行了研究,预测该蛋白分子量为42.86 kDa,属于不稳定类蛋白质,其蛋白质二级结构以α-螺旋为主;蛋白质氨基酸序列与其他8种同源基因氨基酸序列间同源性都比较高;此外,成功构建了该基因的正、反义植物表达载体pCAMBIA-Ubi-LpGCS+和pCAMBIA-Ubi-LpGCS-,并通过农杆菌介导法获得转正、反义基因烟草。对转基因植株和野生型烟草进行镉离子胁迫试验,生理生化指标测试结果表明镉离子胁迫处理10 d后,转LpGCS+植株中MDA含量低于野生型,光合色素含量与POD、SOD、CAT活性均高于野生型;而转LpGCS-植株中MDA含量高于野生型,光合色素含量与POD、SOD、CAT活性均低于野生型。综上所述,LpGCS基因在烟草中的过量表达可以提高植株的耐镉胁迫能力,为进一步利用该基因转化多年生黑麦草培育抗重金属植株奠定基础。     

多年生黑麦草种质资源物候期和形态性状

为评价并筛选具有优异特性的多年生黑麦草(Lolium perenne)种质资源,本研究选取99份多年生黑麦草种质资源,对其物候期及8个形态性状进行观测和分析,并依据各形态指标开展主成分分析和聚类分析.结果表明:供试种质的全生育期为252.0～310.0 d,形态性状均表现出了丰富的变异,其变异系数为22.63%～44....     

不同外植体对多年生黑麦草愈伤组织诱导的影响

对多年生黑麦草的3个品种进行愈伤组织诱导,选取成熟种子、成熟胚、胚轴、胚根4种外植体。结果表明,胚轴、胚根诱导效果较差,成熟胚在愈伤组织的诱导率、鲜重及愈伤质量方面均优于成熟种子。2,4-D浓度在2~4mg/L,6-BA浓度为0.025mg/L时有利于成熟胚诱导产生愈伤组织;成熟种子为外植体时,2,4-D浓度在5~8mg/L,6-BA浓度在0.025mg/L或0.2mg/L有利于成熟种子诱导产生愈伤组织。2,4-D浓度为2mg/L,6-BA浓度为0.5mg/L时成熟胚和成熟种子诱导的愈伤组织鲜重均达到最大。特拉华在愈伤组织的诱导率、增殖速度及愈伤质量方面表现较优,托亚次之,尤文图斯较差。AC和LH有利于植株的再生。