Lolium arundinaceum | |
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Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Clade: | Commelinids |
Order: | Poales |
Family: | Poaceae |
Subfamily: | Pooideae |
Genus: | Lolium |
Species: | L. arundinaceum |
Binomial name | |
Lolium arundinaceum (Schreb.) Darbysh. | |
Synonyms | |
List
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Lolium arundinaceum, tall fescue is a cool-season perennial C3 species of grass which native to Europe. It occurs on woodland margins, in grassland and in coastal marshes. It is also an important forage grass with many cultivars that used in agriculture and is used as an ornamental grass in gardens, and sometimes as a phytoremediation plant.
Most publications have used the names Festuca arundinacea or, more recently, Schedonorus arundinaceus for this species, but DNA studies appear to have settled a long debate that it should be included within the genus Lolium instead.
Tall fescue is a long-lived tuft-forming perennial (called a bunchgrass in the US), with erect to spreading hollow flowering stems up to about 165 cm (5'6") tall (exceptionally up to 200 cm) which are hairless (glabrous), including the leaf sheaths, but with a short (1.5 mm) ligule and slightly hairy (ciliate) pointed auricles that can wrap slightly around the stem. The leaf blade is flat, up to about 10 mm wide, and also glabrous, but rough on both sides and the margins. The tillers (non-flowering stems) are typically shorter but otherwise similar to the culms. The leaves have prominent veins running parallel the entire length of the blade. Emerging leaves are rolled in the bud. Note that most grasses are folded not rolled, which make this a key identification feature on tall fescue.
Flowering typically occurs from early June until late August, with an erect to slightly nodding open panicle up to about 40 cm (1'6") long. The branches are normally in pairs, each of which has 3-18 spikelets, which are 9-15 mm long and comprise 4-8 bisexual florets and two short, unequal glumes. The lower glume has only 1 nerve whereas the upper one has 3. The lemmas typically have a short (3 mm) awn arising just below the tip. Each floret has 3 stamens with anthers about 3-4 mm long. The fruit is a nut or caryopsis with the seed tightly enclosed by the hardened lemma and palea. [1] [2] [3] [4]
Tall fescue was first described (as Festuca arundinacea) by the German naturalist Johann Christian Daniel von Schreber in 1771. Its inclusion within the genus Festuca was due to the similarity of the flowers and inflorescences. However, there has been much debate since 1898 about its relationship to the genus Lolium , largely because of hybridization with Lolium perenne (species in separate genera are far less likely to form hybrids than those within the same genus). [5] [6] Recent DNA studies have shown that it should indeed be considered a ryegrass (Lolium) rather than a fescue (Festuca) because these species are more closely related to each other, despite the fact that ryegrasses have inflorescences of spikes rather than racemes. [7] [8]
Its chromosome number is 2n = 42. [2]
Tall fescue has become an invasive species and noxious weed in native California grasslands and habitats, such as the California coastal prairie plant community.
In its native European environment, tall fescue is found in damp grasslands, river banks, and coastal area. [9] The British National Vegetation Classification lists it as a minor component in a range of grassland types, but it is particularly characteristic of its own MG12 Festuca arundinacea community, which is a tussocky type of pasture that occurs in brackish grazing marshes around the south and west coasts. This vegetation type is also home to some uncommon plants such as parsley water-dropwort and slender spike-rush. [10] Tall fescue is also found in a number of salt marsh and maritime cliff communities. [11] In New Zealand, where it is introduced, the species is particularly prolific in salt marshes, where it is often dominant. [12]
Its Ellenberg values in Britain are L = 8, F = 6, R = 7, N = 6, and S = 1, which show that it favours damp, brightly sunny places with neutral soils and moderate fertility, and that it can occur in slightly brackish situations. [13]
Tall fescue can be found growing in most soils of the southeast including marginal, acidic, and poorly drained soils and in areas of low fertility, and where stresses occur due to drought and overgrazing. [14] These beneficial attributes are now known to be a result of a symbiotic association with the fungus Neotyphodium coenophialum . [15]
This association between tall fescue and the fungal endophyte is a mutualistic symbiotic relationship (both symbionts derive benefits from it). The fungus remains completely intercellular, growing between the cells of the aboveground parts of its grass host. The fungus is asexual, and is transmitted to new generations of tall fescue only through seed, a mode known as vertical transmission. [15] Thus in nature, the fungus does not live outside the plant. Viability of the fungus in seeds is limited; typically, after a year or two of seed storage the fungal endophyte mycelium has died, and seeds germinated will result in plants that are endophyte-free. [16]
The tall fescue–endophyte symbiosis confers a competitive advantage to the plant. Endophyte-infected tall fescue compared to endophyte-free tall fescue deters herbivory by insects and mammals, [17] bestows drought resistance, [18] and disease resistance. [19] In return for shelter, seed transmission, and nutrients the endophyte produces secondary metabolites. These metabolites, namely alkaloids, are responsible for increased plant fitness. Alkaloids in endophytic tall fescue include 1-aminopyrrolizidines (lolines), ergot alkaloids (clavines, lysergic acids, and derivative alkaloids), and the pyrrolopyrazine, peramine.
The lolines are the most abundant alkaloids, with concentrations 1000 higher than those of ergot alkaloids. Endophyte-free grasses do not produce lolines, and, as shown for the closely related endophyte commonly occurring in meadow fescue, Neotyphodium uncinatum , [20] the endophyte can produce lolines in axenic laboratory culture. However, although N. coenophialum possesses all the genes for loline biosynthesis, [21] it does not produce lolines in culture. [20] So in the tall fescue symbiosis, only the interaction of the host and endophyte produces the lolines. [15] Lolines have been shown to deter insect herbivory, and may cause various other responses in higher organisms. Despite their lower concentrations, ergot alkaloids appear to significantly affect animal growth. Ergots cause changes in normal homeostatic mechanisms in animals that result in toxicity manifested through reduced weight gains, elevated core temperatures, restricted blood flow, reduced milk production and reproductive problems. Peramine, like the ergot alkaloids, is found in much lower concentrations in the host compared with loline alkaloids. Its activity has been shown to be primarily insecticidal, and has not been linked to toxicity in mammals or other herbivores. [22]
Tall fescue was introduced into the United States in the late 19th century, but it did not establish itself as a widely used perennial forage until the 1940s. As in Europe, tall fescue has become an important, well-adapted cool season forage grass for agriculture in the US with many cultivars. In addition to forage, it has become an important grass for turf and soil conservation. Tall fescue is the most heat tolerant of the major cool season grasses. Tall fescue has a deep root system compared to other cool season grasses. This non-native grass is well adapted to the "transition zone" Mid Atlantic and Southeastern United States and now occupies over 35,000,000 acres (140,000 km2). [23]
The dominant cultivar grown in the United States is Kentucky 31. In 1931 E. N. Fergus, a professor of agronomy at the University of Kentucky, collected seed from a population on a hillside in Menifee County, Kentucky although formal cultivar release did not happen until 1943. Fergus heard about this "wonder grass" while judging a sorghum syrup competition in a nearby town. He wanted to see this grass because it was green, lush, and growing well on a sloped hillside during a drought. While visiting the site he was impressed and took seed samples with him. With this seed he conducted variety trials, initiated seed increase nurseries, and lauded its performance. It was released as Kentucky 31 in 1943 and today it dominates grasslands in the humid southeastern US. In 1943, Fergus and others recognized this tall fescue cultivar as being vigorous, widely adaptable, able to withstand poor soil conditions, resistant to pests and drought. [23] It is used primarily in pastures and low maintenance situations.
Breeders have created numerous cultivars that are dark green with desirable narrower blades than the light green coarse bladed K-31. Tall fescue is the grass on the South Lawn of the White House. [24]
The predominant cultivar found in British pastures is S170. [25]
Horses are especially prone to reproductive problems associated with tall fescue, often resulting in death of the foal, mare, or both. [26] Horses which are pregnant may be strongly affected by alkaloids produced by the tall fescue symbiont. Broodmares that forage on infected fescue may have prolonged gestation, foaling difficulty, thickened placenta, or impaired lactation. In addition, the foals may be born weakened or dead. [27] To moderate toxicosis, it is recommended that pregnant mares should be taken off infected tall fescue pasture for 60–90 days before foaling as late gestation problems are most common. [28]
Fescue toxicity in cattle appears as roughening of the coat in the summer and intolerance to heat. Cattle that graze on tall fescue are more likely to stay in the shade or wade in the water in hot weather. In the winter, a condition known as "fescue foot" might afflict cattle. This results from vasoconstriction of the blood vessels especially in the extremities, and causes a gangrenous condition. Untreated, the hoof might slough off. Additionally, cattle may experience decreased weight gains and poor milk production when heavily grazing infected tall fescue pasture. [23] To deter toxicosis cattle should be given alternative feed to dilute their infected tall fescue intake.
Carbon cycling in terrestrial ecosystems is a major focus of research. Terrestrial carbon sequestration is the process of removing carbon dioxide from the atmosphere via photosynthesis and storing this carbon in either plant or soil carbon pools. Increases in soil organic carbon help aggregate the soil, increase infiltration, reduce erosion, increase soil fertility, and act as long lived pools of soil carbon. Many studies have suggested that long term endophyte-infected tall fescue plots increase soil carbon storage in the soil by limiting the microbial and macrofaunal activity to break down endophyte infected organic matter input and by increasing inputs of carbon via plant production. [29] While the long term studies tend to show an increase in carbon storage, the short term studies do not. However, short term studies have shown that the endophyte association results in higher above- and belowground plant biomass production compared to uninfected plants, [29] as well as a decrease in certain microbial communities. [30] Site-specific characteristics, such as management and climate, need to be further understood to realize the ecological role and potential benefits of tall fescue and the endophyte association as it relates to carbon sequestration.
New cultivars are being bred and tested every year. A major focus of research is producing endophyte-infected tall fescue cultivars that have no detrimental effects to livestock while keeping the endophytic effects of reduced insect herbivory, disease resistance, drought tolerance, and extended growing season. Novel endophytes, also referred to as "friendly" endophytes, are symbiotic fungi that are associated with tall fescue, but do not produce target alkaloids in toxic concentrations. A widely used and tested novel endophyte is called MaxQ and is grown in the tall fescue grass host Georgia-Jesup. [31] This cultivar of tall fescue-novel endophyte combination produces ergot alkaloids at near zero levels while maintaining the concentration of other alkaloids.
Forage is a plant material eaten by grazing livestock. Historically, the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage.
Lolium is a genus of tufted grasses in the bluegrass subfamily (Pooideae). It is often called ryegrass, but this term is sometimes used to refer to grasses in other genera.
Festuca (fescue) is a genus of flowering plants belonging to the grass family Poaceae. They are evergreen or herbaceous perennial tufted grasses with a height range of 10–200 cm (4–79 in) and a cosmopolitan distribution, occurring on every continent except Antarctica. The genus is closely related to ryegrass (Lolium), and recent evidence from phylogenetic studies using DNA sequencing of plant mitochondrial DNA shows that the genus lacks monophyly. As a result, plant taxonomists have moved several species, including the forage grasses tall fescue and meadow fescue, from the genus Festuca into the genus Lolium, or alternatively into the segregate genus Schedonorus.
Festuca ovina, sheep's fescue or sheep fescue, is a species of grass. It is sometimes confused with hard fescue.
British NVC community MG12 (Festuca arundinacea grassland) is one of the mesotrophic grassland communities in the British National Vegetation Classification system. It is one of three types of mesotrophic grassland classified as grass-dominated inundation communities.
Claviceps purpurea is an ergot fungus that grows on the ears of rye and related cereal and forage plants. Consumption of grains or seeds contaminated with the survival structure of this fungus, the ergot sclerotium, can cause ergotism in humans and other mammals. C. purpurea most commonly affects outcrossing species such as rye, as well as triticale, wheat and barley. It affects oats only rarely.
Lolium pratense, meadow fescue is a perennial species of grass, which is often used as an ornamental in gardens, and is also an important forage crop. It grows in meadows, roadsides, old pastures, and riversides on moist, rich soils, especially on loamy and heavy soils.
Epichloë is a genus of ascomycete fungi forming an endophytic symbiosis with grasses. Grass choke disease is a symptom in grasses induced by some Epichloë species, which form spore-bearing mats (stromata) on tillers and suppress the development of their host plant's inflorescence. For most of their life cycle however, Epichloë grow in the intercellular space of stems, leaves, inflorescences, and seeds of the grass plant without incurring symptoms of disease. In fact, they provide several benefits to their host, including the production of different herbivore-deterring alkaloids, increased stress resistance, and growth promotion.
Epichloë coenophiala is a systemic and seed-transmissible endophyte of tall fescue, a grass endemic to Eurasia and North Africa, but widely naturalized in North America, Australia and New Zealand. The endophyte has been identified as the cause of the "fescue toxicosis" syndrome sometimes suffered by livestock that graze the infected grass. Possible symptoms include poor weight gain, elevated body temperature, reduced conception rates, agalactia, rough hair coat, fat necrosis, loss of switch and ear tips, and lameness or dry gangrene of the feet. Because of the resemblance to symptoms of ergotism in humans, the most likely agents responsible for fescue toxicosis are thought to be the ergot alkaloids, principally ergovaline produced by E. coenophiala.
Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennial plants, most species live more than one season. Tussock grasses are often found as forage in pastures and ornamental grasses in gardens.
Ergovaline is an ergopeptine and one of the ergot alkaloids. It is usually found in endophyte-infected species of grass like Tall fescue or Perennial Ryegrass. It is toxic to cattle feeding on infected grass, probably because it acts as a vasoconstrictor.
Brown patch is a common turfgrass fungal disease that is caused by species in the genus Rhizoctonia, usually Rhizoctonia solani. Brown patch can be found in all of the cool season turfgrasses found in the United States. Brown patch is most devastating to: Bentgrass, ryegrass, Annual bluegrass, and Tall fescue. Brown patch is also found in Kentucky bluegrass and Fine fescue but this is rare or does minimal damage. Brown patch is known as a foliar disease, so it does not have any effect on the crown or roots of the turf plant.
A loline alkaloid is a member of the 1-aminopyrrolizidines, which are bioactive natural products with several distinct biological and chemical features. The lolines are insecticidal and insect-deterrent compounds that are produced in grasses infected by endophytic fungal symbionts of the genus Epichloë. Lolines increase resistance of endophyte-infected grasses to insect herbivores, and may also protect the infected plants from environmental stresses such as drought and spatial competition. They are alkaloids, organic compounds containing basic nitrogen atoms. The basic chemical structure of the lolines comprises a saturated pyrrolizidine ring, a primary amine at the C-1 carbon, and an internal ether bridge—a hallmark feature of the lolines, which is uncommon in organic compounds—joining two distant ring carbons. Different substituents at the C-1 amine, such as methyl, formyl, and acetyl groups, yield loline species that have variable bioactivity against insects. Besides endophyte–grass symbionts, loline alkaloids have also been identified in some other plant species; namely, Adenocarpus species and Argyreia mollis.
Plant use of endophytic fungi in defense occurs when endophytic fungi, which live symbiotically with the majority of plants by entering their cells, are utilized as an indirect defense against herbivores. In exchange for carbohydrate energy resources, the fungus provides benefits to the plant which can include increased water or nutrient uptake and protection from phytophagous insects, birds or mammals. Once associated, the fungi alter nutrient content of the plant and enhance or begin production of secondary metabolites. The change in chemical composition acts to deter herbivory by insects, grazing by ungulates and/or oviposition by adult insects. Endophyte-mediated defense can also be effective against pathogens and non-herbivory damage.
Lolium giganteum, giant fescue, is a woodland grass that grows on neutral to base-rich soils, often near streams or other damp places. It is native to Europe and much of Asia and has been introduced to parts of North America.
Lolium rigidum is a species of annual grass. Common names by which it is known include annual ryegrass, a name also given to Italian ryegrass, rigid ryegrass, stiff darnel, Swiss ryegrass and Wimmera ryegrass. It is a native of southern Europe, northern Africa, the Middle East and the Indian subcontinent and is grown as a forage crop, particularly in Australia, where it is also a serious and economically damaging crop weed.
Perennial ryegrass staggers is poisoning by peramine, lolitrem B, and other toxins that are contained in perennial ryegrass, and produced by the endophyte fungus Epichloë festucae which can be present in all parts of the grass plant, but tends to be concentrated in the lower part of the leaf sheaths, the flower stalks and seeds. This condition can affect horses, cattle, sheep, farmed deer and llamas. It regularly occurs in New Zealand and is known spasmodically from Australia, North and South America, and Europe.
Lolitrem B is one of many toxins produced by a fungus called Epichloë festucae var. lolii), which grows in Lolium perenne. The fungus is symbiotic with the ryegrass; it doesn't harm the plant, and the toxins it produces kill insects that feed on ryegrass. Lolitrem B is one of these toxins, but it is also harmful to mammals. The shoots and flowers of infected ryegrass have especially high concentrations of lolitrem B, and when livestock eat too much of them, they get perennial ryegrass staggers. At low doses the animals have tremors, and at higher doses they stagger, and at higher yet doses the animals become paralyzed and die. The blood pressure of the animals also goes up. The effect of the lolitrem B comes on slowly and fades out slowly, as it is stored in fat after the ryegrass is eaten. The condition is especially common in New Zealand and Australia, and plant breeders there have been trying to develop strains of fungus that produce toxins only harmful to pests, and not to mammals.
Epichloë festucae is a systemic and seed-transmissible endophytic fungus of cool season grasses.
Epichloë hybrida is a systemic, asexual and seed-transmissible endophyte of perennial ryegrass within the genus Epichloë. An interspecies allopolyploid of two haploid parent species Epichloë typhina and Epichloë festucae var. lolii, E. hybrida was first identified in 1989, recognized as an interspecific hybrid in 1994, but only formally named in 2017. Previously this species was often informally called Epichloë typhina x Epichloë festucae var. lolii, or referenced by the identifier of its most well-studied strain, Lp1. Epichloë hybrida is a symbiont of perennial ryegrass where its presence is almost entirely asymptomatic. The species has been commercialized for the benefits of its anti-insect compounds in a pasture setting, although it is now more commonly used as an experimental model system for studying interspecific hybridization in fungi.