L1 is a slide of a stained transverse section through a plant leaf. Fig. 2.1 shows an image of some epidermal cells from the surface of a different leaf, viewed under a microscope. 8 µm [Figure 2.1] Plants of the same species were grown for 6 months. Each plant was grown in a different percentage of shade. After 6 months, the mean specific leaf area was recorded, as shown in Table 2.1. Table 2.1 | percentage shade | mean specific leaf area /cm²g⁻¹ | |---|---| | 5 | 118 | | 40 | 140 | | 50 | 151 | | 60 | 153 | | 90 | 206 | [Figure 2.2]

1. (a)(i)Draw a large plan diagram of the whole section on L1. Use a sharp pencil. Use one ruled label line and label to identify a trichome.[5]
2. (a)(ii)Observe the upper epidermis and the layer of cells beneath it on the section of the leaf on L1. Select a group of four adjacent cells, two cells from the upper epidermis and two cells from the layer below the upper epidermis. Each cell must touch at least two of the other cells. • Make a large drawing of this group of four cells. • Use one ruled label line and label to identify a chloroplast in one cell.[5]
3. (b)(i)Measure the lengths of the epidermal cells using the lines M1, M2, M3, M4 and M5 in Fig. 2.1 and calculate the mean length of the lines. Show your working. M1 = M2 = M3 = M4 = M5 = mean length of lines =[2]
4. (b)(ii)Using the scale bar and the mean length of lines from (b)(i), calculate the mean actual length of the epidermal cells. Show your working. mean actual length = µm[2]
5. (c)(i)Plot a graph of the data shown in Table 2.1 on the grid in Fig. 2.2. Use a sharp pencil.[4]
6. (c)(ii)Using the data in Table 2.1 and your graph in Fig. 2.2, describe the trend in mean specific leaf area.[2]
7. (c)(iii)Use the graph in Fig. 2.2 to find the mean specific leaf area in 30% shade. mean specific leaf area cm² g⁻¹[1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.