translocation

How does glucose travel from the leaves to the rest of the plant?

via the phloem

What do the substances in the phloem need to be?

soluble in water

Where does the phloem take substances from and to?

the source to sink

What’s the source?

Places where substances are produced or sourced

What’s the sink?

the place where the substance is needed

How does sucrose enter the companion cell?

The H+ions and transported out of the cytoplasm actively by a companion cell, causing a concentration gradient to form and for H+ ions to return to the cytoplasm via co transport with sucrose

What is glucose converted to undergo translocation?

sucrose

How does sucrose get from the companion cell to the sieve tube elements?

via diffusion

What happens when lots of sucrose enters the sieve tube element?

water potential decreases

What does the decrease in water potential in the phloem cause?

Water to move from the xylem to the sieve tube element of the phloem via osmosis

What does water moving from the xylem to the phloem cause?

An increase in the hydrostatic pressure in the sieve tube element in the phloem

What does phloem unloading cause?

a higher water potential in the sieve tube element near the sink

What does the increased water potential in the sieve tube element near the sink cause?

water to move out of the phloem via osmosis and for the hydrostatic pressure to decrease within that sieve tube element

What does the decreased hydrostatic pressure at the sieve tube element near the sink cause?

A hydrostatic pressure gradient to form between the sieve tube element near the source and the sieve tube element near the sink

What does the hydrostatic pressure gradient caused by the varying hydrostatic pressures between the source and the sink cause?

sucrose to move from the source to the sink