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To determine the effect of a plant parasite on the plant’s growth, an experiment was carried out with alfalfa plants - VCE - SSCE Biology - Question 4 - 2005 - Paper 1
Question 4
To determine the effect of a plant parasite on the plant’s growth, an experiment was carried out with alfalfa plants. Two alfalfa seeds were planted into each of 30... show full transcript
Worked Solution & Example Answer:To determine the effect of a plant parasite on the plant’s growth, an experiment was carried out with alfalfa plants - VCE - SSCE Biology - Question 4 - 2005 - Paper 1
Step 1
Why was the dry weight of the plants measured?
Answer
The dry weight of the plants was measured because it provides an indication of plant growth or biomass. Dry weight is a more reliable measure than wet weight since it eliminates the variability caused by water content. Since different plants may contain varying amounts of water, measuring dry weight gives a true representation of the plant's growth.
Step 2
Suggest what the root parasites were obtaining from the plant.
Answer
The root parasites were likely obtaining nutrients such as sugars, glucose, or other essential materials necessary for their growth and survival. These nutrients are critical for the parasites as they rely on the host plant for sustenance.
Step 3
Given the data above, state one conclusion about the effect of the parasites on the alfalfa.
Answer
The data suggests that the presence of the root parasites, Odontites rubra and Rhinanthus serotinus, negatively impacts the growth of the alfalfa plants. The total dry weight of the plants decreased significantly in the groups with parasites compared to the group with only alfalfa plants, indicating that the parasites may reduce the overall health and growth of the host plants.