Adaptations for transport in plants 3.2

What is the structure of the root?

•Vascular bundle (innermost part) - contains xylem in x shape and phloem tubes around it.

•pericycle surrounds vascular bundle

•endodermis - cells have casparain strips made of Suberin meaning passage of water and nutrients must take symplast route and this means plant can regulate uptake

•cortex - transports water and nutrients

•epidermis - root hair cells nutrients absorbed by the root to the vascular bundle

What are the different routes across the cortex?

•apoplast pathway is the transport route through cell wall, it is the fastest route across the cortex, water moves by cohesion, and it can’t continue at endodermis due to casparian strip so water forced into symplast route

•Symplast pathway is transport route through cytoplasm by osmosis and then passes between cells through the plasmodesmata

•Vacuolar route is a pathway where water moves between cytoplasm and vacuole and then from cell to cell via plasmodesmata, it is the slowest route due to membrane crossing

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