If a tree in North India flowers three times a year (in October,January,and July),it is considered to be:

What is the site of perception of photoperiod necessary for the induction of flowering in plants?

Define/Explain: Photoperiodism.

When all parts except the leaves of a short-day plant are covered with a light-proof cover and then subjected to short-day light/dark treatment,it will produce flower buds. When a portion of this plant is grafted onto another plant of the same species which has been prevented from flowering by excessive exposure to light,this latter plant will also produce flower buds. Which is the best inference from this result?

If the dark period is interrupted by red light in $SDP$,the plant will show:

The pigment phytochrome is involved in: