the xylem Flashcards
what is the xylem
dead, hollow, plant cells that have no end cell walls stacked together** to form a continous columnar tube**
what is the function of the xylem
- to transport water and inorgnic ions from the root hair cells in the soil up to the leaf itself
features of the xylem vessel
- no end cell walls
- no protoplasm
- no cellular contents
- dead
- contains lignin
what is unique about the xylems cell wall
it has a secondary cell wall inside the primary cellulose cell wall - made of lignin
what is the importance of lignin
- provides structural support and prevents the cell wall collapsing under tension or high pressure
- prevents water leakage/ water loss by being waterproof
what is different in a xylems cell wall depending on its age
its lignification
2 types of xylem vessels
- protoxylem
- metaxylem
what is protoxylem
the xylem found in the root hair cells that enable elongation from their lignification
what type of lignification does protoxylem have and what is their adaption to function
- annular
- spiral
adaption to function- the lignification
- doesnt restrict elongation of the xylem vessel which **makes it able to grow **
- also allows for a long time for the vessel to be fully lignified and mature
what is the metaxylems tpes of lignification and what are their adaption to function
- reticulate
- pitted
adaption to function-
the reticulate is interconnected
the pores in the pitted vessel allow rapid movement of water and ions from the xylem to adjacent cells and to the surrounding cells
where is metaxylem found
mature parts of the plant
what is the adaption to function of the general xylem in terms of transport of water
(why are they dead, hollow, neverending etc)
- able for water to move around with less resistance
- no cellular contents allows the xylem to carry a greater volume of water
