Which of the following pigments absorbs red and far-red light?

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

What do you understand by photoperiodism and vernalisation? Describe their significance.

Most of the plants are seasonal due to

What will happen if several bulbs are lighted in soybean fields at night?

$A$ 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?