Chapter 36, Problem 1TYK

Why are N, P, and K considered limiting nutrients?

a. They tend to be found in extremely low levels within plants.

b. Their presence limits the availability of micronutrients.

c. Their availability tends to limit plant growth.

d. They limit the amount of cation exchange taking place in roots.

Summary Introduction

Introduction:

The concept of limiting nutrients explains that the nutrient that is in short supply relative to the other nutrients will exhaust first and will limit the growth of the plant cells.

Answer to Problem 1TYK

Correct answer:

The availability of nutrients tends to limit the growth of the plant.

Explanation of Solution

Explanation/Justification for the correct answer:

Option (c) is given that availability of limiting nutrients tends to limit the growth of a plant. Nitrogen is an essential nutrient and a key element in the growth of the plant. Phosphorus aids in the transfer of energy from sunlight to the plants and regulates the growth of the plant. Potassium regulates the closing and opening of stomata and the production of ATP in plants. If these nutrients are exhausted, the plant growth will be affected. Hence, Option (c) is correct.

Explanation for incorrect answers:

Option (a) is given that limiting nutrients are found at very low levels in the plants. Nitrogen, phosphorus, and potassium are macronutrients and these are present in large quantity. So, it is a wrong answer.

Option (b) is given that presence of limiting nutrients limits the availability of micronutrients. Micronutrients or trace elements are iron, boron, chlorine, magnesium, zinc, and copper. The presence of macronutrients does not affect the levels of micronutrients. So, it is a wrong answer.

Option (d) is given that limiting nutrients limit the cation exchange occurring in the plants. Limiting nutrients do not interfere with the exchange of cations that is occurring in the roots. So, it is a wrong answer.

Hence, options (a), (b), and (d) are incorrect.

Conclusion

Nutrients are necessary for the growth and metabolism of the plant. Nitrogen, potassium, and phosphorus are crucial for the plant growth as they are the limiting nutrients, but are macronutrients. They do not exhibit their effect on limiting the availability of micronutrients and the exchange of cations in the roots of plants.