tracheid उदाहरण वाक्य

Then, the first tracheids of the transition zone are formed, where the radial size of cells and thickness of their cell walls changes considerably.
Their stems are similar in structure to woody dicots except that most gymnosperms produce only tracheids in their xylem, not the vessels found in dicots.
During evolution the strength of the tracheid cell walls was enhanced, the ability to conduct water was lost and the size of the pits was reduced.
He performed a comparative analyses of the vasculatures of living and fossil gymnosperms and came to the conclusion that the storage parenchyma has been derived from tracheids.
However, by the time they become competent to conduct water, all xylem tracheids and vessels have lost their cytoplasm and the cells are therefore functionally dead.

Wider tracheids allow water to be transported faster, but the overall transport rate depends also on the overall cross-sectional area of the xylem bundle itself.
Both prostrate and upright stems have a central strand of conducting tissue which contains simple tracheids, so that " Stockmansella " is a vascular plant.
The size of tracheids is limited as they comprise a single cell; this limits their length, which in turn limits their maximum useful diameter to 80 ?m.
Nitrogen availability in the rooting medium also affects the size and structure of tracheids formed in the long lateral roots of white spruce ( Krasowski and Owens 1999 ).
A tracheid, once cavitated, cannot have its embolism removed and return to service ( except in a few advanced angiosperms which have developed a mechanism of doing so ).