Mass flow of sucrose down the phloem occurs as water enters sieve tubes by osmosis, increasing hydrostatic pressure where sucrose enters (source), and water leaves sieve tubes by osmosis at the sink where sucrose is actively removed, decreasing pressure, creating a gradient for flow.
- low wp in sieve tubes where sucrose enters - water moves by osmosis from xylem into sieve tubes - increase in water volume causes increase in hydrostatic pressure - sucrose actively transported from sieve tubes into sink by companion cell - low wp at sink - water moves by osmosis from sieve tubes into sink - decrease in water volume reduces hydrostatic pressure - mass flow of sucrose down hydrostatic pressure gradient
| Front | How does the mass flow of sucrose down the phloem occur? |
|---|---|
| Back | - low wp in sieve tubes where sucrose enters - water moves by osmosis from xylem into sieve tubes - increase in water volume causes increase in hydrostatic pressure - sucrose actively transported from sieve tubes into sink by companion cell - low wp at sink - water moves by osmosis from sieve tubes into sink - decrease in water volume reduces hydrostatic pressure - mass flow of sucrose down hydrostatic pressure gradient |
Tags: plant_transport
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