Role of Phytochromes
Phytochromes are the leaf pigments which are used to initiate photoperiodism in plants. The flowering plants uses the photoreceptor proteins which are usually present in the leaves to detect the period of darkness and light. Phytochromes are of two types: Active form and inactive forms. Active forms predominates during the day whereas the inactive form predominates during the night. In the absence of light the active form of phytochromes reverts to an inactive form.
Photoperiodism: Meaning, Process and Examples
Photoperiodism is a biological response of plants and animals to change in the proportion of dark and light. Garner and Allard first studied photoperiodism in plants in 1920. “Photo” means light and “period” means the length of time. Plants require light to bloom. The duration when the plant is required to bloom is known as critical photoperiod. Photoperiodism helps to determine the flowering season of different types of plants.