Photoperiodism - Plant Physiology

 Photoperiodism 

• Response of plant to day light period specially flowering behaviour is called photoperiodism

• The term photoperiodism was coined by Garner and Allard (1920).

 They classified plants into three categories: 

a. Short day plants: 

• Such plants require the day length less than 12 hours for flower initiation..

 • E.g. tobacco, soybean, rice, generally kharif crops and many tropical plants.

 b. Long day plants:

 • Such plants require more than 14 hours day light for flower initiation.

 • E.g. wheat, barley, sugar beet, castor, generally Rabi crops

 c. Day neutral plants:

 • Such plants are unaffected by the day length e.g. maize, tomato, buckwheat, sunflower, cotton, cucumber etc.