Holdfasts vary in shape and form depending on both the species and the substrate type. The holdfasts of organisms that live in muddy substrates often have complex tangles of root-like growths. These projections are called haptera and similar structures of the same name are found on lichens. The holdfasts of organisms that live in sandy substrates are bulb-like and very flexible, such as those of sea pens, thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted. The holdfasts of organisms that live on smooth surfaces (such as the surface of a boulder) have flattened bases which adhere to the surface. The organism derives no nutrition from this intimate contact with the substrate, as the process of liberating nutrients from the substrate requires enzymatically eroding the substrate away, thereby increasing the risk of organism falling off the substrate.
The claw-like holdfasts of kelps and other algae differ from the roots of land plants, in that they have no absorbent function, instead serving only as an anchor.[2]
holdfast, biology, other, uses, holdfast, disambiguation, holdfast, root, like, structure, that, anchors, aquatic, sessile, organisms, such, seaweed, other, sessile, algae, stalked, crinoids, benthic, cnidarians, sponges, substrate, holdfast, torn, from, floor. For other uses see Holdfast disambiguation A holdfast is a root like structure that anchors aquatic sessile organisms such as seaweed other sessile algae stalked crinoids benthic cnidarians and sponges to the substrate 1 Holdfast torn from the sea floor by a stormEocrinoid holdfasts on an Ordovician hardground in Utah Holdfasts vary in shape and form depending on both the species and the substrate type The holdfasts of organisms that live in muddy substrates often have complex tangles of root like growths These projections are called haptera and similar structures of the same name are found on lichens The holdfasts of organisms that live in sandy substrates are bulb like and very flexible such as those of sea pens thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted The holdfasts of organisms that live on smooth surfaces such as the surface of a boulder have flattened bases which adhere to the surface The organism derives no nutrition from this intimate contact with the substrate as the process of liberating nutrients from the substrate requires enzymatically eroding the substrate away thereby increasing the risk of organism falling off the substrate The claw like holdfasts of kelps and other algae differ from the roots of land plants in that they have no absorbent function instead serving only as an anchor 2 References edit D N Thomas 2002 Seaweeds Natural History Museum London ISBN 978 0 565 09175 0 Attenborough D 1984 The Living Planet p 232 amp 235 Collins BBC ISBN 0 563 20207 6 nbsp This Alga related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Holdfast biology amp oldid 1148341936, wikipedia, wiki, book, books, library,
