Chapter 23, Problem 21A

Summary Introduction

To write:

The reason why short-day and long-day is not the best descriptive terms of flowering plants.

Introduction:

A short-day plant flowers when it is exposed daily to some of hours of darkness that is more than its critical period. For example, a short-day plant ought to flower whilst uncovered to sixteen hours of darkness. Short-day plants flower in the period of winter, spring or fall, whilst the range of hours of night is extra than the range of hours of light. A long-day plant flowers whilst the range of hours nights is much less than it critical period. These plants flower in the course of the summer. 

Explanation of Solution

Short-day plants form flowers only while day duration is much less than approximately 12 hours. If those are uncovered to greater than 12 hours of light per day, bloom formation does not occur. Other plants require only a short night time to flower. These are termed "long day" plants. These blooms only after they acquire greater than 12hours of light. Many of our summer time blooming plant life and lawn greens are long day plants, which include asters, coneflowers, California poppies, lettuce, spinach and potatoes. These all bloom while the times are lengthy, in the course of our temperate summers.

Conclusion

It is very difficult to describe a plant as short- day and long-day flowering plant because there is no exact critical period for blooming of flowers that is the reason why it is not the best descriptive terms for flowering plants.