Sir,A flash of red light followed by flash of far red light given during the middle of night to a Short day plant,then what will happen and why?
Photoperiodism may be defined as the reaction of plants and animals to the length of the day and the night. Some plants need to be exposed to sunlight for a particular duration of time to induce flowering. It is the reason behind the seasonal blooming of flowers.
For example, tulips flower in spring and lilies flower in winter.
Certain animals also depend on the daylength for a variety of their characteristics.
Photoperiodism in Plants
Most angiosperms (flowering plants) use photoperiodism to determine when to flower. To do that they use one of the photoreceptor protein present in their body, such as cryptochrome or phytochrome.
There is a well defined critical duration. This critical duration is different for different plants. Based on this duration, plants can be categorized in three categories:
- The plants which need the exposure of light more than this duration are called long day plants (LDP).
- Those which need an exposure less than this duration are called short day plants (SDP).
- Plants which do not have this constraint for the process of flowering are known as day neutral plants (DNP).
Plants which are LDP, such as chrysanthemums, hibiscus, petunias and spinach, can never be found where the length of the day is less. Similarly, SDP plants, such as cotton, spinach, rice and sugarcane are not typically found where the length of the night is less. Research and investigation has shown that darkness is more important to SDPs than light is to LDPs. That is to say that LDPs are more likely to flower even if their period in the light is interrupted by darkness for a certain amount of time than SDPs, if their period in darkness is interrupted by sudden bright light.
Day neutral plants, on the other hand, do not let light or darkness affect the timing of their flowering. Instead, their flowering is based on other factor such as age or some external stimulus. Rose, tomato and cucumber may be cited as examples.
Photoperiodism may be defined as the reaction of plants and animals to the length of the day and the night. Some plants need to be exposed to sunlight for a particular duration of time to induce flowering. It is the reason behind the seasonal blooming of flowers.
For example, tulips flower in spring and lilies flower in winter.
Certain animals also depend on the daylength for a variety of their characteristics.
Photoperiodism in Plants
Most angiosperms (flowering plants) use photoperiodism to determine when to flower. To do that they use one of the photoreceptor protein present in their body, such as cryptochrome or phytochrome.
There is a well defined critical duration. This critical duration is different for different plants. Based on this duration, plants can be categorized in three categories:
- The plants which need the exposure of light more than this duration are called long day plants (LDP).
- Those which need an exposure less than this duration are called short day plants (SDP).
- Plants which do not have this constraint for the process of flowering are known as day neutral plants (DNP).
Research and investigation has shown that darkness is more important to SDPs than light is to LDPs. That is to say that LDPs are more likely to flower even if their period in the light is interrupted by darkness for a certain amount of time than SDPs, if their period in darkness is interrupted by sudden bright light.
Day neutral plants, on the other hand, do not let light or darkness affect the timing of their flowering. Instead, their flowering is based on other factor such as age or some external stimulus. Rose, tomato and cucumber may be cited as examples.
