What is a bordered pit?
What is a bordered pit?
Bordered pits are cavities in the lignified cell walls of xylem conduits (vessels and tracheids) that are essential components in the water-transport system of higher plants.
What is simple pit and bordered pit?
Simple pits are areas of the tracheid cell wall so thin that nutrient rich solutions can pass through them, to be dispersed throughout the plant. Bordered pits have the secondary cell wall extending over the pit with a small hole in the secondary cell wall that allows the water to pass through.
What is the difference between pits and bordered pit?
The key difference between bordered pit and simple pit is that bordered pit has a secondary wall overarching the pit cavity forming a border while simple pit does not have an arching of the secondary wall and narrowing of the pit towards the lumen. A pit is a thin depressed portion of the secondary cell wall.
How are bordered pits formed?
Bordered pits form in radially expanding and expanded primary-walled cambial derivatives and, when produced in opposition to one another in adjoining cells, bordered-pit pairs develop (Figs.
What is torus in botany?
The ‘torus’ is an impermeable, typically lignin-based thickening at the centre of the pit membrane, which regulates flow of water by preventing cavitation, in case an air bubble gets introduced.
What is torus in biology?
Biology. Receptacle (botany), the thickened part of a stem from which the flower and fruit parts grow.
Where is torus present in plant?
A torus is present in intervascular pit membranes in the wood of Daphne odora and D.
What is torus structure?
In geometry, a torus (plural tori, colloquially donut or doughnut) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis that is coplanar with the circle.
What is mean pit?
1 : a cavity or hole in the ground usually made by digging a gravel pit. 2 : an area set off from and often sunken below surrounding areas a barbecue pit a theater’s orchestra pit. 3 : a small hole or dent on a surface.
What are torus in pits?
The torus and margo are characteristic features of bordered pit-pairs in gymnosperms, such as Coniferales, Ginkgo, and Gnetales. In other vascular plants, the torus is rare. The pit membrane is separated into two parts: a thick impermeable torus at the center of the pit membrane, and the permeable margo surrounding it.
What is a torus in anatomy?
Medical Definition of torus 1 : a doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle. 2 : a smooth rounded anatomical protuberance (as a bony ridge on the skull) a supraorbital torus.
How do you define a torus?
1 : a doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle. 2 : a smooth rounded anatomical protuberance (as a bony ridge on the skull) a supraorbital torus.