In some plants,the cold treatment may be replaced by the application of

Effect of photoperiod on growth and development of plants,especially on flowering,is called

Which of the following factors exclusively affects reproduction in seasonal breeders,both plants and animals?

Some plants require a period of light greater than a critical duration for flowering. Such plants are called $..............$.

The name 'phytochrome' was given by

$A$ group of plants shows flowering in a $12$ hour day and $12$ hour night cycle. When the night phase of another group of the same plants is interrupted by a brief flash of light, flowering does not occur. In which of the following groups would you place these plants?