The following points highlight the two main approaches of photoperiodic time measurement. Approach # 1. The Conception of Physiological Clock of Erwin Bunning: This is also known as biological clock or oscillating clock. Bunning performed several experiments in Kalanchoeblossfeldiana. In this species the petals open in the morning and close down in the evening. It is also possible to maintain [...]
Vernalization has multiple interactions with photoperiodism. Thus, a cold requirement for flowering appears to be associated with a specific photoperiod. The most well quoted instance is that of need for vernalization and LD which leads to flowering in late spring or early summer. However, a cold requirement may also be accompanied by a SD photoperiodic response. Vernalization is also known [...]
In this article we will discuss about:- 1. Meaning of Photoperiod 2. Photoperiodic Response Groups 3. Photoinductive Cycles 4. Genetic Approach 5. Flowering Hormone. Subject-Matter of Photoperiod: Two American plant physiologists, W.W. Garner and H.A. Allard (1920) while working at the USA department of Agriculture Research Laboratories at Beltsville, Maryland made observations that tobacco variety, Maryland Mammoth, grew vegetatively in [...]