Plant Vascular System Flashcards
What does herbaceous mean?
Doesn’t produce wood.
What does dicotyledonous mean?
Seedlings have 2 leaves instead of 1.
Xylem Vessels?
Dead, carry water and mineral ions.
Xylem tracheids?
Dead, carry water and mineral ions but are slightly narrower that vessels.
Xylem fibres?
Dead, provide support, elasticity and tensile strength.
Xylem parenchyma?
Alive, acts as ‘packing’ tissue to support vessels.
Structure of Xylem?
They are dead and do not contain any cytoplasm.
Cell walls impregnated with lignin.
Small pores in lignin layer (boarded pits).
No end cell walls.
Function of Xylem structure?
Minimises resistance to flow of water.
Prevents water loss and vessel from collapsing.
Allows water to move laterally in and out of vessel.
Can transport a continuous column of water.
What do Phloem tissue transport?
Assimilates
Structure of Sieve Tube Elements.
No nucleus and very little cytoplasm.
End cell walls have holes in (forming sieve plates).
Function of Sieve Tube Element structure.
Leaves space for sap to flow and reduces resistance.
Allows sap to move from one sieve tube element to another.
Structure of Companion cells.
Many mitochondria to produce ATP.
Directly linked to sieve tube elements by plasmodesmata.
Function of Companion Cell structure.
ATP needed for loading phloem with sucrose.
Gaps in cell wall where cytoplasm is continuous.
