1. These are plants which require less exposure to light for a period less than the critical duration.

2. If night is interrupted by light then there is no flowering.

3. These need light of short wave lengths whose value is below critical point.

4. These produce flowering in winter.

7. If days are interrupted by darkness then no effect.

Long day plants :

1. These are plants which require the exposure to light for a period exceeding a well defined critical duration.

2. If night is interrupted by light then no such effect on flowering.

3. These need light whose value is above critical point.

5. These produce flowers in summer.

6. If days are interrupted by darkness then no flowers.