Impotance of day length ( photoperiodism ) in flowering of plants was first shown in

Options

A. Lemna
B. tobacco
C. cotton
D. Petunia

Answer

B

Explanation

Photoperiodism was first discovered by Garner and Allard (1920, 1922). They observed that malyland mammoth variety of tobacco could be made to flower only by reducing the light hours with artificial darkning.
On the basis of photoperiodic response to flowering plants have been divided into short day plants (tobacco), long day plant (e.g. wheat, hanbane), short long day plants. (e.g. Campanula), long short day plants (e.g. Bryophyllum) intermediate plants (e.g. wild kidney bean) and day neutral plants (e.g cotton)