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Figure 2 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake - Edexcel - GCSE Biology - Question 2 - 2020 - Paper 1
Question 2
Figure 2 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake. (a) Water lilies have stomata on the upper surface of the leaves. Explain w... show full transcript
Worked Solution & Example Answer:Figure 2 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake - Edexcel - GCSE Biology - Question 2 - 2020 - Paper 1
Step 1
Explain why water lilies have no stomata on the lower surface of the leaves.
Answer
The lower surface of the water lily leaf is submerged in water, meaning it is not in contact with air. Therefore, gas exchange cannot occur effectively in this submerged area, as water prevents the entry of oxygen and carbon dioxide, leading to reduced or no transpiration.
Step 2
Step 3
Describe how this sugar is transported from the leaves to the flowers of the water lily.
Answer
The glucose produced during photosynthesis is converted to sucrose, which is then transported through the phloem. This process occurs via translocation, where sugars are dissolved in the water and actively transported to the flowers.
Step 4
Explain why this non-indigenous plant now covers the whole surface of the lake.
Answer
The conditions in the lake are suitable for the growth of the water lily due to factors like sunlight and nutrient availability. Additionally, the water lily has outcompeted native plants for resources. Without natural herbivores to control its growth, the plant has proliferated and now covers the entire surface.