Question

What factor of light has proven to be the most critical to floral development? Length of uninterrupted light periods Length of uninterrupted dark periods Light quality Maximum exposure to light

Answer 1

Length of uninterrupted dark periods is the factor of light that is proved to be most critical to floral development.

Step-by-step explanation:

• Photoperiodism is the main factor which determines floral development in a plant. This controls the flowering response according to the ‘relative lengths of periods of light or darkness’. A photoperiod is defined as the “recurring cycle of ‘uninterrupted light’ and dark periods that a plant is exposed to within a 24-hour period.” Accordingly, plants are classified:

1. Long-day plant: Needs >12 hours of sunlight or <12 hours of uninterrupted darkness
2. Short-day plant: Needs <12 hours of sunlight or >12 hours of uninterrupted darkness
3. Neutral: Photoperiod does not involve in floral development

• When a short-day plant is under increased periods of ‘uninterrupted darkness’, it will bloom more than when a long-day plant is exposed to more sunlight. Hence, it is proved that length of uninterrupted darkness is critical for floral blooming.