1. Explain the difference between autotrophic and heterotrophic nutrition .
2. What is meant by essentiality? What is the difference between an element and a beneficial element? Describe the steps you would go through in order to determine the essentiality or nonessentially of an element for a higher plant.
3. List the 17 elements that are essential for the growth of all higher plants. Be able to identify one or more principal structural or metabolic roles for each essential element.
4. Deficiencies of iron, magnesium, and nitrogen all cause chlorosis. Iron chlorosis develops only between the veins of young leaves while chlorosis due to both magnesium and nitrogen deficiencies develops more generally in older leaves. Explain these differences. Why does each deficiency lead to chlorosis and why are the patterns different ?
5. For what reasons might a soil rich in calcium supply too little phosphorous for plant growth ?
6. What is a chelating agent? Explain how chelating agents help to maintain iron availability in nutrient cultures and soils.
7. What is meant by critical toxicity level? Which elements are most likely to be both essential and toxic to plans?
8. There are currently 17 elements known to be essential for higher plants. Is it possible that other elements might be added to this list in the future? Explain your answer.