Exam 38: Plant Nutrition

Figure 38.1 -Iron shortage is the most common human nutritional deficiency in the world.Plants are the major source of iron in most diets,so researchers are interested in understanding their mechanism of iron intake and in developing iron-rich crops.Recently,researchers showed (Vert et al.,IRT1,an Arabidopsis transporter essential for iron uptake from the soil and for plant growth.Plant Cell 14 [2002]:1223-33)that under iron-deficient conditions,the IRT1 gene is responsible for most of the iron uptake activity in roots.To demonstrate the importance of IRT1 for iron accumulation,researchers measured leaf iron content in irt1-1 mutants containing deactivated IRT1.Mutant plants were grown in iron-poor soil (irt1-1 in graph)and soil rich with iron (irt1-1 +Fe in graph).Wild-type (WT)plants grown in iron-poor soil were used as a control.Which of the graphs represent the data researchers might have received in their experiment?

Which of the following is the most energy-demanding process?

What is the charge on the inside of a plant cell plasma membrane?

Where are ion channels localized?

For most plants,a higher amount of humus in the soil is

To understand the role of zinc in plant growth and development,you are growing a tomato plant using hydroponics.Which plant organs do you expect to have defects if you provide the plant with a solution devoid of zinc?

The micronutrient iron is abundant in soil,but often unavailable to plants due to insolubility.Knowing that the reaction Fe(OH)₃ + 3H⁺ ↔ Fe³⁺ + 3H₂O occurs,and assuming all soil samples have same total amount of iron in them,which type of soil would you predict to have the highest amount of soluble iron?

Which elements are most often the limiting nutrients for plant growth?

Which of the following is not true about an essential nutrient?

What type of soil is most difficult for roots to penetrate?

After mutagenesis and screening take place,you have found a mutant that is able to grow in soil with high copper content.Protein analysis shows that the concentration of metallothioneins in the mutant is different from that in normal plants.How does the concentration of metallothioneins likely differ in the mutant relative to the normal plant?

Give two reasons that relatively few plants thrive in bogs.

Soil leaching is usually

What major benefits do plants and mycorrhizal fungi receive from their symbiotic relationship?

Which elements are responsible for the greater part of plant wet weight?

How would you expect the root system of a plant grown by hydroponics to compare to the root system of a plant grown in soil?

What is the function of proton pumps localized in the plant plasma membrane?