Coralloid roots are just like lateral roots, but highly specialized to contain cyanobacteria.
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Ossicaulis species have gills that are adnexed, adnate or somewhat decurrent and a stipe that is centrally or laterally attached to the cap. The hyphal system is monomitic (meaning only generative hyphae are present), the trama is regular, and there are clamp connections in the hyphae. Spores are small and ellipsoidal in shape. The cap cuticle features coral-shaped (coralloid) hyphae, and there are additionally coralloid to narrowly club-shaped cheilocystidia in the hymenium.
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Since Z. floridana is a cycad, which are the only group of gymnosperms that form nitrogen-fixing associations, it depends on microbes as a source of nitrogen. It forms a symbiotic relationship with nitrogen-fixing cyanobacteria, which live in specialized roots called coralloid roots and are green in color despite not actively photosynthesizing. The filamentous cyanobacteria belonging to the genus Nostoc, which is able to form symbiosis with a wide range of organisms, inhabits the mucilage in the microaerobic and dark intercellular zone in between the inner and outer cortex of coralloid roots. This zone is transversed and connected by elongated Zamia cells.
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Diaporthe toxica is a plant endophyte and occasionally a plant pathogen.Williamson et al. (1991) Formation of subcuticular coralloid hyphae by Phomopsis leptostromiformis. Plant Disease 75:1023-1026 D. toxica produces secondary metabolites that result in toxicoses of animals such as lupinosis of sheep.
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In addition, endomycorrhizae are present in roots and allow for increased absorption of nutrients and water. Symbiotic blue-green algae are also found in the coralloid (i.e. upward growing) roots. They assist the plant by fixing nitrogen thus giving the plant essential nutrients in exchange for protection.
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The crowded, stiff, narrow leaflets are long and have strongly recurved or revolute edges. The basal leaflets become more like spines. The petiole or stems of the sago cycad are long and have small protective barbs. Roots are called coralloid with an Anabaena symbiosis allowing nitrogen fixation.
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Hamburg 30.32 (2002): 125–155 (see p. 129). This species is very similar to the apostulate Canoparmelia caroliniana, showing the same colour, size and reticulate maculae. C. caroliniana, however, has true isidia. Big coralloid pustules that in some cases become sorediate are a characteristic feature for C. albomaculata.
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EcM fungal partners characteristically suppress root hair development of their plant symbiont. They can also increase root branching by inducing cytokinins in the plant. These branching patterns can become so extensive that a single consolidated mantle can envelop many root tips at a time. Structures like this are called tuberculate or coralloid ectomycorrhizas.
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Cycads are long-lived and slow-growing, with slow recruitment and population turnover. All cycads possess 'coralloid' (meaning coral-like) roots. These roots contain symbiotic cyanobacteria that fix gaseous nitrogen from the atmosphere and provide essential nitrogenous compounds to the plant. This can be a great advantage, as many cycads grow in nutrient-poor habitats.
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Plants do not reproduce until 10 to 20 years of age and are thought to live over 60 years. They regrow from the ground after bushfire. Seedlings of Macrozamia spiralis have a tuber and coralloid roots that rise up above the ground containing cyanobacteria. These exist in a symbiotic relationship with their cycad host by nitrogen fixation.
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Niebla usneoides is distinguished by a thallus divided into numerous subtubular more or less linear shaped branches, to 4 cm high and 8 cm across, that are fringed above with spiculiform branchlets and by short coralloid isidia (isidium) along margins. The branches become terminally whip-like, or abruptly curved. Pycnidia and apothecia are absent. Similar species are Niebla suffnessii and Niebla isidiaescens.
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They are fragile structures and may break off and be distributed by wind, animals, and splashing raindrops. In terms of structure, isidia may be described as warty, cylindrical, clavate (club- shaped), scale-like, coralloid (coral-shaped), simple, or branched. Examples of isidiate lichens include members of the genera Parmotrema and Peltigera. C. palmicola photographed through a dissecting microscope (x40) showing isidia.
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C. striata near Barrier Lake, Alberta. Note the two pale leaves sheathing the lower part of the stem, and part of the coralloid rhizome showing on the left behind the base of the stem. Like other coralroot orchids, the plant takes its name from its coral-shaped rhizomes. It has an erect stem about tall that may be red, pink, purple, or yellow-green to almost white.
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Its pustulae are found as marginal and submarginal, its coralloid being isidioid, at times exhibiting granular soredia apically. Its medulla is white, while its underside possesses a rugose and veined light brown center, as well as a rugose, veined and papillate margin. Its rhizinae are simple, measuring between long, being coloured brown and being few in number. Apothecia and pycnidia are absent in Canoparmelia albomaculata.
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Seedlings of Macrozamia communis have a tuber and coralloid roots that rise up above the ground containing cyanobacteria. These exist in a symbiotic relationship with the cycad by nitrogen fixation. The seeds of the burrawang are a good source of starch but are poisonous to eat unless treated. The Cadigal people pounded and soaked the seeds in water for a week, changing the water daily.
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Their roots have small secondary roots. The coralloid roots develop at the base of the stem at or below the soil surface. Male and female sporophylls are spirally aggregated into determinate cones that grow along the axis. Female sporophylls are simple, appearing peltate, with a barren stipe and an expanded and thickened lamina with 2 (rarely 3 or more) sessile ovules inserted on the inner (axis facing) surface and directed inward.
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A young Thomas Pennant, c.1740 A visit to Cornwall in 1746–47, where he met the antiquary and naturalist William Borlase,Cunningham, 1834. awakened an interest in minerals and fossils which formed his main scientific study during the 1750s. In 1750, his account of an earthquake at Downing was inserted in the Philosophical Transactions of the Royal Society, where there also appeared in 1756 a paper on several coralloid bodies he had collected at Coalbrookdale, Shropshire.
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Cox and his colleagues found that BMAA is produced by symbiotic cyanobacteria found in the coralloid roots of cycads. Other than that, fruit bats or flying foxes, feeds on cycad seeds, and were a common food for the Chamorros. The bats bioaccumulate BMAA in their fat, and eating even a few bats would cause a dose of BMAA similar to levels that produced disease symptoms in the earlier animal models. The content of free BMAA in fruit bats was up to 3 mg/g (approximately 30 mM), while that in the broth in which the fruit bats had been cooked was up to 3 mg/250 ml.
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Cycads are gymnosperms (naked seeded), meaning their unfertilized seeds are open to the air to be directly fertilized by pollination, as contrasted with angiosperms, which have enclosed seeds with more complex fertilization arrangements. Cycads have very specialized pollinators, usually a specific species of beetle. They have been reported to fix nitrogen in association with various cyanobacteria living in the roots (the "coralloid" roots). Cycads all over the world are in decline, with four species on the brink of extinction and seven species have fewer than 100 plants left in the wild. 23,420 species of vascular plant have been recorded in South Africa, making it the sixth most species-rich country in the world and the most species-rich country on the African continent.
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The cap cuticle, which is not clearly differentiated from the cap tissue, consists of thin-walled, interwoven hyphae 2.5–9 μm in diameter. The tissue of the universal veil on the cap consists of more or less parallel and erect rows of roughly spherical, and ellipsoid to broadly ellipsoid cells, up to 78 by 65 μm and spindle- to club-shaped cells up to 125 by 30 μm. These latter cells are terminal or in short, terminal chains, and are borne on moderately abundant, thin-walled, branched, interwoven, sometimes nearly coralloid hyphae, 3–9.5 μm diameter with a few scattered oleiferous (oil-containing) hyphae, 5–12.5 μm diameter. The distribution of hyphae at the stem base is similar to that on the cap, but with more filamentous hyphae.
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