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Figure 2 shows the leaves and flowers of water lily plants (Nymphaea dorata) 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 dorata) on a lake. (a) Water lilies have stomata on the upper surface of the leaves. Explain wh... show full transcript
Worked Solution & Example Answer:Figure 2 shows the leaves and flowers of water lily plants (Nymphaea dorata) 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
Water lilies have stomata primarily on the upper surface of their leaves because the lower surface is submerged in water. In this submerged environment, the lower surface is not in contact with air, which is essential for gas exchange. Therefore, there is no need for stomata to allow for this process, resulting in a lack of stomata on the lower surface.
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 into sucrose for transport within the plant. This sugar is primarily transported through the phloem, where it can be dissolved in water and moved using translocation. Active transport may also be involved in loading sucrose into the phloem.
Step 4
Explain why this non-indigenous plant now covers the whole surface of the lake.
Answer
The non-indigenous water lily plant likely covers the whole surface of the lake due to several factors:
- The conditions in the lake were favorable for its growth and photosynthesis, similar to its native environment.
- Being a vigorous species, it outcompeted local plants for resources like light and nutrients.
- Additionally, the absence of natural herbivores to keep its growth in check allowed it to proliferate unchecked, leading to its dominance in the lake.