help! biology homework water movement in plants

hi people i need with these question thank you

A beaker was filled with a dye solution. An actively transpiring plant was then pushed under the surface of the dye and the stem cut.

4a) Explain why the dye moved up the stem towards the leaves.
b) What happened to the tension in the water column in the xylem when the stem was cut?
c) As a result of this what happened to the length of tghe water columns in the cut pieces of stem?
d) Use your answers to (b) and (c) to help explain why the dye went into the xylem in the root end of the stem.

Reply 1

Golden Maverick

starfrogsplash

hi people i need with these question thank you

A beaker was filled with a dye solution. An actively transpiring plant was then pushed under the surface of the dye and the stem cut.

4a) Explain why the dye moved up the stem towards the leaves.
The plant is respiring and transpiration is also taking place. This means water is being lost in the leaves so is drawn up from the roots via the xylem.

b) What happened to the tension in the water column in the xylem when the stem was cut?
The tension was released as previously the 'pull' from the leaves is being counteracted by capillary action when the stem is out of water. When cut underwater it is now aqain a continuous column.

The other 2 questions are a bit strange. The water column length would be shortened as you have cut the stem, but I don't see how that is important.
Dye moves into the plan at the root end because that is where the xylem opens into the water, as there are no roots this is the only way it can take up water.