The area of photoperception in plants is

Phytochrome plays an important role in

The site of perception of light in plants for flowering is

Some varieties of wheat are known as spring wheat while others are called winter wheat. The former variety is sown and planted in spring and is harvested by the end of the same season. However,winter varieties,if planted in spring,fail to flower or produce mature grains within a span of a flowering season. Explain,why?

Which is not a requirement of vernalisation?

Define/Explain: Photoperiodism.