Plant mineral requirementsEdexcel International A Level Biology: Flashcards

Exam questions on Plant mineral requirements

1. A farmer notices that the older, lower leaves of her wheat crop have turned pale yellow and the plants are shorter than normal, while the youngest leaves are still green. A soil test shows that the soil is very low in nitrate ions.
   Suggest why the older leaves show the symptoms before the youngest leaves.2 marks
2. A gardener grows tomato plants in compost. Some of the plants show yellowing between the veins of their leaves, and others have young leaves that are distorted. The gardener thinks that the plants are short of mineral ions.
   Explain why a tomato plant short of magnesium ions grows poorly.2 marks
3. A student investigated the effect of mineral deficiency on the growth of barley seedlings. Seedlings were grown for 21 days in four aerated culture solutions: a complete solution, a solution lacking nitrate, a solution lacking magnesium and a solution lacking calcium. At the end, the mean dry mass per seedling was 148 mg in the complete solution, 61 mg without nitrate, 97 mg without magnesium and 112 mg without calcium.
   Explain why the student also grew seedlings in a complete solution, and describe two variables that the student should control.3 marks