Tapetum

(redirected from tapeta)
Also found in: Dictionary, Medical.

tapetum

[tə′pēd·əm]
(botany)
A layer of nutritive cells surrounding the spore mother cells in the sporangium in higher plants; it is broken down to provide nourishment for developing spores.
(neuroscience)
A reflecting layer in the choroid coat behind the neural retina, chiefly in the eyes of nocturnal mammals.
A tract of nerve fibers forming part of the roof of each lateral ventricle in the vertebrate brain.

Tapetum

 

a layer (occasionally several layers) of cells in the sporangia of the majority of higher plants; it is rich in nutrients and physiologically active substances. The tapetum may originate from the archespore, as in leptosporangiate ferns and selaginellas. It may be the inner layer of the sporangium wall, as in eusporangiate ferns, plants of the order Lycopodiales, and plants of the genus Equisetum, or the inner layer of a microsporangium, as in seed plants.

The substances in tapetum cells are used by the developing sporocytes and spores; in seed plants they are used by the pollen grains as well. The tapetum cells either form a periplasmodium, or amoeboid tapetum, or they maintain their position, forming a secretory tapetum. There is no tapetum in the sporangia of Psilotophyta or Isoëtales.

References in periodicals archive ?
Conclusion Half-brother Daaree scored on Tapeta at Wolverhampton.
And Southwell's PS8million refurbishment will be completed when Fibresand makes way for Tapeta, which is widely used in America and Australia.
"She is doing very well and should run her race provided she handles the Tapeta."
It has taken considerable time and effort to get used to working with Tapeta, as well as new working practices for race days and overall track maintenance.
Dickinson has two Tapeta tracks at his stables in Maryland and also hopes to utilise many other new technologies, including a hyperbaric chamber, an auxiliary energy system and a bio-mechanical analyser.
Tapeta is a synthetic surface consisting of sand, fiber, rubber and a unique brand of wax.
Bin Surour said: "They are nice horses who go well on the Tapeta. It is a good race as you would expect but they are in good form and should run well."
Dickinson will now concentrate all his efforts into developing the all-weather surface Tapeta, which is being increasingly used worldwide.
Cats have iridescent tapeta in their eyes forgathering the palest traces of light; but all that gathered scattery light in their eyes, then, prevents cats from perceiving fine details.
Conway and Walters' restoration is achieved by the insertion of two fragments of Livy: (1) `auratae vaginae, aurata baltea illis erant', quoted explicitly from Livy Book 9 by Nonius (286.4= 194.20M); (2) `erant et equorum inaurata tapeta', quoted by Probus in Instituta Artium (GL IV 129-30).
Wolverhampton was cleared of upwards of six inches of snow yesterday but with temperatures as low as -11C forecast overnight, how the Tapeta reacts will be key to the meeting going ahead.
A successful floodlit trial evening has already taken place with horses galloping on the tapeta.