1. Mineral nutrients
(a) are not essential to plant growth, since all a plant needs is water and CO2.
(b) contribute little to the weight of a plant.
(c) enter plants via the stomata.
(d) are organic nutrients.
2. Professor Arun claims to have discovered a new macronutrient required for plant growth. Most of Professor Arun’s colleagues are skeptical of this claim. Why might they consider it unlikely?
(a) All the nutrients required for plant growth have already been found.
(b) It is very difficult to prove that a plant needs a certain nutrient.
(c) Plants need thousands of nutrients; a new one is not significant.
(d) Any nutrient needed in large amounts has probably been found already.
3. Soil could be deficient in any of the following nutrients. If you had to supply one of them, which would be needed in the smallest amount?
(a) iron (b) phosphorus
(c) nitrogen (d) potassium
4. Which of the following is a symptom of magnesium deficiency?
(a) yellowing of younger leaves’ prior to yellowing of older leaves.
(b) enhanced plant growth, since magnesium is toxic to plants.
(c) chlorosis
(d) decreased transpiration
5. Topsoil
(a) is the relatively inert upper layer of soil.
(b) does not retain water.
(c) is a mixture of rock fragments, living organisms, and humus.
(d) is uniform in texture.
6. The roots of many aquatic plants have special structures that project above the surface of the water. For example, cypress trees (which grow in swamps) have knees that extend upward above water level. Which of the following is the most logical function of these structures?
(a) obtaining carbon dioxide for photosynthesis
(b) nitrogen fixation
(c) obtaining oxygen for the roots
(d) transpiration
7. The clay particles in soil are important because they
(a) are composed of nitrogen needed by plants.
(b) eliminate spaces for air and facilitate drainage.
(c) fill spaces and keep oxygen out of the soil.
(d) are charged and hold ions needed by plants.
8. Soil can easily become deficient in _____, because these ions are negatively charged and do not stick to negatively charged clay particles.
(a) potassium. (b) calcium.
(c) magnesium. (d) nitrate.
9. Fertilizers are usually enriched in
(a) iron, manganese, and zinc.
(b) calcium, boron, and carbon.
(c) nitrogen, phosphorus, and potassium.
(d) molybdenum, copper, and magnesium.http://www.blogger.com/img/blank.gif
10. Nitrogen-fixing bacteria in the soil
(a) convert nitrates to N2.
(b) convert ammonia into ammonium.
(c) convert atmospheric nitrogen into ammonia.
(d) use nitrates to make amino acids that plants can use.
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