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The diagram shows a vascular bundle from a flowering plant - HSC - SSCE Biology - Question 27 - 2016 - Paper 1
Question 27
The diagram shows a vascular bundle from a flowering plant. (a) On the diagram, clearly label a xylem vessel. (b) A mutation in this species causes the walls of th... show full transcript
Worked Solution & Example Answer:The diagram shows a vascular bundle from a flowering plant - HSC - SSCE Biology - Question 27 - 2016 - Paper 1
Step 1
On the diagram, clearly label a xylem vessel.
Answer
To label a xylem vessel on the diagram, identify the thick-walled cells typically located near the center of the vascular bundle. These cells are usually larger in diameter compared to surrounding cells. Clearly mark one of these cells as 'Xylem Vessel' with an arrow pointing towards it.
Step 2
Explain why the leaves of these mutant strains will wilt more easily.
Answer
The xylem is responsible for transporting water and nutrients from the roots to the leaves of the plant. In mutant strains where the walls of the xylem vessels are significantly reduced in thickness, the structural support provided by these walls is compromised. This reduction in thickness can lead to greater collapsibility of the xylem vessels under pressure.
As a result, during periods of high transpiration or low water availability, these weakened xylem vessels may not effectively conduct water, leading to insufficient hydration of the leaves. This inadequate water supply can cause the leaves to lose turgor pressure, making them more prone to wilting.