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1.
高羊茅的生理生态及其生化特性研究进展   总被引：31，自引：8，他引：23  
在研究和大量借鉴国内外最新研究成果的基础上,系统论述和报道了高羊茅在水分、温度、酸碱盐以及重金属等逆境胁迫下的生理变化,也包括内生真菌和植物生长调节剂对高羊茅的影响.同时,对高羊茅的生化特性的研究进展作了报道,主要包括高羊茅品种的生化鉴定以及以转基因技术应用为主的基因工程等方面的研究.展望了高羊茅在生理生态以及生化特性方面的研究趋势,特别是高羊茅的抗性机理以及有关分子生物学方面的研究将成为未来研究的重点和热点,为今后深入开展高羊茅的研究和利用提供科学依据.  相似文献   

2.
内生真菌对苇状羊茅和多年生黑麦草影响的研究进展   总被引：7，自引：4，他引：3  
张颖  韩建国 《草业科学》2004,21(7):59-65
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.  相似文献   

3.
旷宇  南志标  田沛 《草业学报》2016,25(2):160-168
本试验以带Epichloё内生真菌(E+)及不带内生真菌(E-)中华羊茅种子为研究材料,研究其水引发后,在NaCl胁迫条件下的萌发情况。结果表明,NaCl胁迫显著降低中华羊茅种子发芽率、发芽势、发芽指数、胚芽长、胚根长和干重。除对照处理外,相对于不带内生真菌的中华羊茅种子,内生真菌能显著提高不同NaCl浓度胁迫条件下中华羊茅种子的萌发力及幼苗生长。水引发与内生真菌可产生互作,在引发时间为20 min时与内生真菌的互作效果最为明显,在不同NaCl浓度胁迫下中华羊茅种子各萌发指标及幼苗生长情况均显著高于其他处理。在对各指标的相关性分析显示,中华羊茅种子的发芽率、发芽势、发芽指数、胚芽长、胚根长和干重相互之间均呈极显著正相关。  相似文献   

4.
苇状羊茅及多年生黑麦草内生真菌的研究进展   总被引：1，自引：1，他引：0  
本文介绍了重要禾本科牧草苇状羊茅及多年生黑麦草内生真菌对家畜的影响、对寄主本身的影响及内生真菌的传播、控制、鉴定和运用。苇状羊茅与多年生黑麦草内生真菌同属枝顶孢霉属(Acremonium),极为相似。苇状羊茅内生真菌导致牛的苇状羊茅中霉症。多年生黑麦草内生真菌造成羊及其它家畜的黑麦草蹒跚病。内生真菌可促进寄主的生长、延长寄主的寿命、抵抗病虫的侵害。内生真菌通过种子传递给牧草后代,牧草生产中用种子贮藏、种子高温处理、种子或植株药物处理控制内生真菌,防止牛的苇状羊茅中毒症和羊的黑麦草蹒跚病。草坪生产中通过接种内生真菌增加草坪草的抗虫、抗病能力,并延长其寿命。  相似文献   

5.
苇状羊茅及多年生黑麦草内生真菌的研究进展   总被引：5，自引：0，他引：5  
本文介绍了重要禾本科牧草苇状羊茅及多年生黑麦草内生真菌对家畜的影响，对寄主本身的影响及内生真菌的传播，控制，鉴定和运用。苇状羊茅与多年生黑麦草内生真菌同属枝顶孢霉属，极为相似，苇状羊茅内生真菌导致牛的苇状羊茅中霉症。多年生黑麦草内生真菌造成羊及其它家畜的黑麦草蹒跚病，内生真可促进寄主的生长，延长寄主的寿命，抵抗病虫的侵害。内生真菌通过种子传递给牧草后代，牧草生产中用种子贮藏，种子高温处理，种子或植  相似文献   

6.
高羊茅种子内生真菌的消毒方法   总被引：4，自引：1，他引：3  
在高羊茅Festuca arundinacea组织培养中最常用的外植体是成熟种子,而种子中共生的半知菌亚门内生真菌Neotyphodium coenophialum使消毒较为困难,污染率高.为了研究温水处理对富含内生真菌的高羊茅种子发芽率、污染率和出愈率的影响,以不同温度(40,50,60℃)、不同时间(10,20,30min)的温水浸泡和次氯酸钠配合使用处理高羊茅种子,并进行发芽率试验和愈伤组织培养.经统计学分析发现,适用于富含内生真菌的高羊茅种子的最佳消毒组合为50℃温水浸泡10min,再经70%酒精处理5min,然后用次氯酸钠处理15min.消毒方法在保证较高种子发芽率的前提下,可降低种子污染率,提高出愈率.该消毒技术对于解决高羊茅因内生真菌造成的严重污染、出愈率低等现象有重要作用,并为高羊茅再生体系构建奠定重要的试验基础.  相似文献   

7.
为探明内生真菌在航天诱变材料黔草1号高羊茅中的分布情况和种类,利用光学显微镜进行镜检观察,对被侵染的航天诱变材料高羊茅展开内生真菌分离培养研究。结果发现,内生真菌的菌丝体普遍存在于试验材料的叶片、叶鞘、茎节间,内生真菌侵染率大小为:茎节叶鞘叶片,侵染差异在航诱材料与对照间(未经航天诱变的原始材料黔草1号)差异不显著(P0.05);对分离条件优化后,发现从试验材料中分离的内生真菌在pH 7.5,25℃黑暗培养的条件下以添加高羊茅煎煮液的马铃薯琼脂糖培养基PSA的培养效果最佳;在pH 7.5,25℃紫外光照/黑暗交替培养的条件下以添加高羊茅煎煮液的水琼脂培养基WSA的促孢效果最佳。  相似文献   

8.
有些禾本科植物内生真菌能为宿主植物带来抗病虫害、抗旱、促进苗期生长和分蘖等性能。研究利用种子中Neotyphodium属内生真菌含菌率不同的苇状羊茅Festuca arundinacea、多年生黑麦草Lolium perenne和野生鹅观草Roegneria kamoji进行了室内发芽试验、室外和人工气候箱内的盆栽试验以及室内外蚜虫接种试验,调查了内生真菌对其宿主苗期生物学特性的影响。发现种子含菌率比较高的苇状羊茅和多年生黑麦草分蘖多,幼苗抗虫性明显提高;种子含菌率比较高的鹅观草发芽率高,出苗整齐,生长快,分蘖多,但幼苗无明显的抗虫性。研究结果进一步说明了禾本科植物内生真菌在农业上具有广阔的利用前景。  相似文献   

9.
披碱草内生真菌对三种草坪草种子与种苗的化感效应   总被引：4，自引：1，他引：3  
以多年生黑麦草、高羊茅和草地早熟禾3种草坪草作为供试对象,用种子萌发法和盆栽法初步测定了披碱草内生真菌的化感效应。结果表明,披碱草内生真菌对3种草坪草种子萌发与生长具有一定的影响作用。种子室内滤纸萌发条件下,披碱草草粉对3种草坪草种子萌发有一定的抑制作用;且内生真菌显著增强了披碱草草粉对多年生黑麦草苗重、对高羊茅的发芽率、根长、苗长、苗重和对草地早熟禾发芽率的抑制作用(P<0.05),显著降低了披碱草草粉对多年生黑麦草的根长和苗长、对高羊茅的根重以及对草地早熟禾根长的抑制作用(P<0.05)。盆栽条件下,披碱草草粉对3种草坪草的生长均有一定的促进作用;且内生真菌显著增强了披碱草草粉对高羊茅初期发芽率的促进作用(P<0.05),显著降低了披碱草草粉对多年生黑麦草的初期发芽率和对草地早熟禾苗长的促进作用(P<0.05)。  相似文献   

10.
脱浩东  杨松  张兴旭  李春杰  南志标 《草业科学》2011,28(12):2107-2111
以多年生黑麦草(Lolium perenne)、高羊茅(Festuca arundinacea)和草地早熟禾(Poa pratensis)为研究对象,用种子萌发法和盆栽法测定了野大麦(Hordeum brevisubulatum)内生真菌(Neotyphodium)对这3种草坪草种子萌发及生长的影响。结果表明,在种子萌发试验中,野大麦草粉对3种草坪草的生长均有一定的抑制作用,而且内生真菌显著增强了野大麦草粉对多年生黑麦草苗长、须根数和对草地早熟禾苗长的抑制作用（P<0.05）;显著降低了野大麦草粉对多年生黑麦草和高羊茅的发芽率及高羊茅苗长的抑制作用（P<0.05）。在盆栽试验中,野大麦草粉对3种草坪草的生长均有一定的促进作用,而且内生真菌显著增强了野大麦草粉对高羊茅和草地早熟禾的苗长和发芽率的促进作用（P<0.05）。  相似文献   

11.
Cattle grazing tall fescue (Festuca arundinacea Schreb.) often develop fescue toxicosis. This condition is thought to be caused by ergot alkaloids produced by the endophyte Neotyphodium coenophialum. Endophytes from wild tall fescue plants, which do not produce ergot alkaloids, were transferred into the endophyte-free tall fescue germplasm, HiMag. The novel associations also lacked the ability to produce ergot alkaloids. Our objective was to determine whether cattle grazing these novel endophyte associations showed signs of fescue toxicosis. At the Fayetteville, Arkansas location, tester steers (n = 72) were assigned to one of four pasture treatments: endophyte-free HiMag tall fescue (HiMag-); 'Kentucky-31' tall fescue infected with its native, toxic endophyte (KY+); and two novel endophyte-infected tall fescue associations, HiMag4 and HiMag9. At the Mount Vernon, Missouri location, steers (n = 54) were used to test three of the four cultivars (HiMag9 was not tested). Ergot alkaloid concentrations in the forage of HiMag4 and HiMag9 were low or undetectable. Respiration rate, rectal temperature, ADG, and hair scores were measured during the grazing period. Blood was collected via jugular venipuncture and used for prolactin, aspartate aminotransferase, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), cholesterol, triglyceride, and creatinine analysis. Weight gains by steers grazing HiMag4 and HiMag9 did not differ from those of steers grazing HiMag-, but were greater than gains (P < 0.05) by steers on the KY+ treatment. Steers grazing KY+ had higher (P < 0.05) respiration rates, rectal temperatures, and hair scores than did steers grazing novel endophyte and HiMag- pastures. Prolactin, ALP, cholesterol, LDH, and triglycerides all were suppressed (P < 0.05) in steers grazing KY+ compared with steers grazing novel endophyte and HiMag- pastures. Steers grazing the novel endophyte tall fescues did not suffer from the decreased weight gains and toxicities associated with fescue toxicosis, resulting in enhanced animal production.  相似文献   

12.
Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.  相似文献   

13.
Livestock grazing endophyte (Acremonium coenophialum Morgan-Jones and Gams)-infected tall fescue (Festuca arundinacea Schreb.) perform poorly due to tall fescue toxicosis, especially when animals are under heat stress. In order to determine whether thiamin promotes recovery from tall fescue toxicosis, 1 or 0 g of thiamin per day, as mononitrate, was fed orally to adult Angus (Bos taurus) cows (380 +/- 8 kg) grazing either tall fescue pasture with and without endophyte or alfalfa (Medicago sativa L.). A tethered grazing system employing a split-plot design was used to estimate intake and components of ingestive behavior. No significant differences attributable to thiamin supplements were seen in rates of intake and biting, grazing time and intake per bite when cows grazed endophyte-infected tall fescue during the first 4 d of exposure. When cows grazed endophyte-infected (greater than 95%) tall fescue with 2,091 micrograms/g loline alkaloids after 4 d of exposure, the untreated animals ingested herbage dry matter (DM) at 1.19 kg/h, whereas the cows receiving thiamin ate 1.57 kg/h (P less than .05). Cattle achieved these rates of DM intake by forming bites of 1.0 and 1.2 g DM at 24 and 26 bites/min when treated with 0 and 1 g of thiamin per day, respectively. Thiamin supplements had no effect on ingestive behavior of cows grazing endophyte-free tall fescue or alfalfa after exposure to these forages for 4 d. Responses to thiamin generally were greater when cattle grazing endophyte-infected tall fescue were exposed to heat stress. Oral thiamin supplementation may alleviate tall fescue toxicosis of beef cattle during warm weather.  相似文献   

14.
Effects of the endophyte Acremonium coenophialum in tall fescue on pregnant mares and foal viability were evaluated. Twenty-two mature pregnant mares were randomly chosen to graze either Kentucky-31 tall fescue that was free from A coenophialum (endophyte-free, EF) or tall fescue infected with A coenophialum (endophyte-present, EP) after the first 90 days of pregnancy through parturition. Concentrations of pyrrolizidine and ergopeptine alkaloids were significantly greater in EP grass, compared with EF pasture. Ten of 11 mares grazing EP pasture had obvious dystocia. Mean duration of gestation was significantly greater for the EP group, compared with the EF group. Foal survivability was severely reduced among mares grazing EP fescue with only 1 foal surviving the natal period. Udder development and lactation were low in mares grazing EP grass. The absence of clinical problems in mares grazing EF grass implicated the endophyte as the causative agent of reproductive problems and perinatal foal mortality in pregnant mares grazing endophyte-infected fescue grass. Caution should be exercised in allowing pregnant mares to graze pastures infected with the endophyte A coenophialum.  相似文献   

15.
Fungal endophyte (Acremonium spp.) toxicity affects sheep and cattle grazing a number of forages, including ryegrasses (Lolium spp.) and tall fescue (Festuca nrundinacea). The endophyte in tall fescue is responsible for ill thrift, as indicated by low weight gains or weight loss(1) and decreased reproductive efficiency(2), and is associated with increased body temperatures. Extensive research has been undertaken in the USA to determine ways of reducing the impact of fescue toxicity on the beef industry(3), whilst New Zealand research is directed toward both ryegrass and fescue endophyte toxicity and its impact on sheep(4)(5) and cattle(6) production. Much of this work involves field evaluations of productive performance in animals fed toxic and non-toxic forage, so that it is important to be sure that treatment effects are due to the endophyte.  相似文献   

16.
Effects of fescue toxicosis on reproduction in livestock.   总被引：3，自引：0，他引：3  
Fescue toxicosis in livestock is due to ingestion of endophyte (Acremonium coenophialum) -infected tall fescue. Understanding mechanisms responsible for decreased calving and growth rates, delayed onset of puberty, and impaired function of corpora lutea in heifers at puberty consuming endophyte-infected fescue is an emerging field in reproductive toxicology. The condition decreases overall productivity through a reduction in reproductive efficiency, reduced weight gains, and lowered milk production. Reproduction in cattle may be further compromised by winter coat retention, increased susceptibility to high environmental temperatures, and light intolerance. Endocrine effects in steers associated with infected tall fescue include reduced prolactin and melatonin secretions and altered neurotransmitter metabolism in the hypothalamus, the pituitary, and pineal glands. Ewes have decreased prolactin and lengthened intervals from introduction of the ram until conception. The endophyte induces prolonged gestation, thickened placentas, large, weak foals, dystocia, and agalactia in pregnant mares. Ergot peptide alkaloids, produced by the endophyte, are suggested as the primary cause of fescue toxicosis. These compounds reduce prolactin, increase body temperatures, and have powerful vasoconstrictive effects. Neurohormonal imbalances of prolactin and melatonin, with restricted blood flow to internal organs, may be the principal causes of aberrant reproduction, growth, and maturation in livestock consuming endophyte-infected tall fescue.  相似文献   

17.
Livestock grazing endophyte (Acremonium coenophialum)-infected tall fescue (Festuca arundinacea Schreb. cv. Kentucky 31) at high ambient temperatures may suffer from fescue toxicosis. Adult Angus cows (Bos taurus) were fed 0 to 1 kg/d of 70% infected tall fescue seed containing about 4.4 g of loline alkaloids in factorial combination with thiamin at 0 or 1 g/d. Cows assigned to the zero level of tall fescue seed received a supplement of equivalent energy and protein. Ingestive behavior was measured at 1330 to 1430 EDT during two 4-d periods in two consecutive weeks in August on alfalfa (Medicago sativa L.) pastures using a tethered grazing system. Alfalfa intake per measured grazing session of cows given tall fescue seed declined linearly (P less than .01) as air temperatures during grazing increased above 25 degrees C, largely because of shorter grazing meals. Thiamin increased alfalfa intake per measured grazing session by extending grazing time. Alkaloids in ingested endophyte-infected tall fescue induce thiamin deficiencies in cattle that result in symptoms of tall fescue toxicosis.  相似文献   

18.
Increased costs of annual establishment of small grain pasture associated with fuel, machinery, and labor are eroding the profitability of stocker cattle enterprises. Interest has therefore increased in development of cool-season perennial grasses that are persistent and high quality. This study occurred on 24 ha (divided into thirty 0.81-ha paddocks) located at the University of Arkansas Division of Agriculture Livestock and Forestry Branch Station, near Batesville. Two tall fescue (Festuca arundinacea Schreb.) cultivars infected with novel endophytes (NE), Jesup infected with AR542 endophyte (Jesup AR542), and HiMag infected with Number 11 endophyte (HM11) were established in September 2002. Jesup AR542 and HM11 were compared with endemic endophyte Kentucky 31 (KY-31) tall fescue; wheat (Triticum aestivum L.) and cereal rye (WR, Secale cereale L.) planted in September 2003, 2004, and 2005; and annual ryegrass [RG, Lolium perenne L. ssp. multiflorum (Lam.) Husnot] planted in September 2004 and 2005. Each year, 3 steers (3.7 steers/ha) were placed on each pasture for fall and winter grazing, and 5 steers (6.2 steers/ha) were placed on each pasture for spring grazing. Animal performance is presented by year in the presence of a year x treatment interaction (P < 0.01). Body weight gain per hectare of steers grazing NE tall fescue was greater (P < 0.01) than those of KY-31 and WR during 2003 to 2004, whereas in 2004 to 2005, BW gain per hectare of steers grazing NE and RG did not differ (P < or = 0.29) and was greater (P < 0.01) than that of WR, which was greater (P < 0.01) than that of KY-31. During 2005 to 2006, BW gain per hectare was greater (P < 0.01) for steers grazing RG than those of NE and WR, which did not differ (P > or = 0.14). Body weight gain per hectare was least (P < 0.01) for steers grazing KY-31. Average net return of NE tall fescue was greater (P < 0.01) than KY-31, but profitability of NE did not consistently differ from cool-season annuals. Across the 3-yr study, NE tall fescue produced net returns per hectare of $219; this level of profitability would require 4 yr for a new planting of NE tall fescue to break even. Novel endophyte tall fescues offer potential benefits related to decreased risk of stand establishment of annual forage crops, longer growing season, and acceptable animal performance.  相似文献   

19.
Most of the tall fescue pastures in the United States are infected by an endophyte, N. coenophialum. The fungus derives nutrients from the plant while supplying the plant with toxins for defense. The most detrimental toxins for animals in tall fescue are ergopeptine alkaloids, especially ergovaline. Ergovaline functions as a dopamine D2 agonist and alters prolactin and several other hormones in the body. Pregnant mares are most susceptible during their last month of gestation. Clinical signs include prolonged gestation, dystocia, retained placentas, agalactia, and dysmature foals that are either stillborn or weak.  相似文献   

20.
The objective of the current study was to delineate changes that occur in serum analytes and blood cellular elements in cattle that graze endophyte-infested (Neotyphodium coenophialum) tall fescue. Tall fescue is grown on more than 35 million acres (14.2 million ha) of pasture in the United States, and three-fourths of the pastures are infected with the endophyte at a 60% or greater level. Tall fescue toxicosis caused by endophyte-produced ergot alkaloids continues to be the most important grass-related disease in the United States, in terms of economic loss to animal producers. However, the agronomic attributes of tall fescue make it an attractive forage species because of its ability to withstand cool temperatures, drought, poor soil conditions, and intensive defoliation from herbivore species, including insects. Tall fescue toxicosis is a complex disease and the need exists to understand the mechanisms of the toxic effects in order to institute effective, prophylactic control measures. Our group previously reported changes that occur in serum biochemical analytes of cattle that graze endophyte-infected tall fescue. An additional year's worth of data have been added, strengthening and corroborating these data. Consistent and significant changes associated with tall fescue toxicosis during the 3-yr study included decreased serum concentrations of cholesterol, globulin (increased albumin/globulin ratio), prolactin, total protein, and copper. The activity of alanine aminotransferase was decreased in serum, whereas an increase in serum concentrations of creatinine and total bilirubin occurred. The present report also documents comparative hemograms of cattle that grazed endophyte-infected or endophyte-free tall fescue over a prolonged period. The mean erythrocyte counts were increased in cattle that grazed endophyte-infected tall fescue, whereas mean corpuscular hemoglobin and mean corpuscular volume were decreased, as were mean eosinophil counts. Thus, repeatable changes have been identified that occur in serum biochemical and blood cellular values of cattle grazing endophyte-infected tall fescue that will aid in understanding the pathogenesis of the disease. In addition, these consistently altered parameters can be used to assess the effectiveness of potential prophylactic treatments.  相似文献   

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