Chapter 30, Problem 1TY

Which of the following can limit plant growth in nature?

1. sunlight
2. water
3. carbon dioxide
4. fixed nitrogen
5. all of the above

Summary Introduction

Introduction:

The primary factors necessary for plant growth are air, light, water, temperature, nutrients. These factors affect the growth hormones making the plant grow quickly or slowly depending on the changes to any of these factors. Light stimulates growth as photosynthesis takes place producing sugars that gets transported to all parts of plants, Water is essential for the transfer of nutrients from soil to plants through roots.

Answer to Problem 1TY

The correct answer is option (e) all of the above

Explanation of Solution

Explanation/justification for the correct answer:

Option (e) all of the above. For plant growth air, light, water, temperature, nutrients, carbon dioxide and nitrogen are essential factors. Even if one of these factors is limited, it will cause stunted growth. Light in adequate amounts and intensity affects the plant shoots and root development. Also, nitrogen and carbon dioxide are essential elements for growth. Another, most important element is water which helps in absorption of nutrients from soil.

Explanation for incorrect answer:

Option (a) sunlight. This is necessary for the development of chlorophyll which helps in photosynthesis. The duration and intensity varies from plant to plant as each will display upper and lower temperature tolerance. Also photosynthesis process increases with increase in temperature. As this is the only option out of others, it is an incorrect answer.

Option (b) water. It is one of the important factors necessary for growth of plants as nutrients are absorbed through it from the soil. The sugar produced by photosynthesis is transported by water to all parts of the plant. As this is only one of the options out of others, it is an incorrect answer.

Option (c) carbon dioxide. This component is absorbed by the plants and in combination with sunlight converts the carbon dioxide and water to produce sugar and oxygen. The sugar is used for growth of plants. Besides carbon dioxide, the other essential factors are light, water. So, this answer is incorrect.

Option (d) fixed nitrogen.Nitrogen in the soil is a critical limiting element for plant growth as it is a major component of chlorophyll which is an important pigment for photosynthesis. It is also essential for amino acids as it is necessary for proteins. This is just one of the factors necessary for plant growth. So, this answer is incorrect.

Conclusion

The most important components that aid in the growth of plant is air, light, water, temperature, nutrients along with carbon dioxide and nitrogen. If one of these factors is limited, it affects the growth of plant. As light is necessary for photosynthesis, the intensity and duration also decides the amount of food produced by the plants. Water, is very important as it helps in absorption of nutrients from the soil.Nitrogen and carbon dioxide are other essential elements for growth.

Hence, the correct answer is option (d) All of the above.