The fabric xylemic (of the Greek xylon , " bois") is a unit including/understanding the xylème, of the Parenchyme of reserve, the associated cells as well as wood-and-bast Rayons. This fabric with the capacity to transport great quantities of water and nutrients since the ground to the photosynthetic factory: the Sheet S.

The xylème is composed of dead cells. Thus, the aqueous solutions do not need to cross plasmic Membrane to forward in the plant what allows him substantial profits of energy by avoiding in particular the use of dependant Pompe ATP. Xylème consists of two parts, the métaxylème (large cells) and the protoxylème (cells of reduced size).

Only at some plants, as at the Gymnosperme S, a transverse wall in the perforated trachéide remains Crible S. These trachéides name trachéides Scalariforme S.

The xylème has various stages of maturity according to the deposits of Lignine to the periphery of its walls. Thus, one distinguishes the trachéides ringed, spiral, réticulées to lead at the most advanced stage which is the punctuated vessel.

This lignin deposit makes it possible to very obtain a tube resisting able to transport the crude sap by a flow under tension. The sap is known as ascending, because it goes up along the xylème.

See too

• Phloem
• vegetable Fabric

Simple: Xylem