Explain with example the three categories of plant based on photoperiodism
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1) Short Day Plants (SDP):
These plants require a relatively short day light period (usually 8-10 hours) and a continuous dark period of about 14-16 hours for subsequent flowering (Fig. 18.1A). Some examples of these plants which are also known as long-night-plants are Maryland Mammoth variety of tobacco (Nicotiana tabacum) Biloxi variety of Soybeans (Glycine max), Cocklebur (Xanthium pennsylvanicum).
i. In short day plants the dark period is critical and must be continuous. If this dark period is interrupted even with a brief exposure of red light (660-665 mµ wavelength), the short day plant will not flower (Fig. 18.1B).
ii. Maximum inhibition of flowering with red light occurs at about the middle of critical dark period.
(2) Long Day Plants (LDP):
These plants require a longer day light period (usually 14-16 hours) in a 24 hours cycle for subsequent flowering. Some examples of these plants which are also called as short night plants are Hyoscyamus niger (Henbane) Spinacea (spinach) Beta vulgaris (Sugar beet).
i. In long day plants the light period is critical.
ii. A brief exposure in the dark period or the prolongation of the light period stimulates flowering in long day plants.
(3) Day Neutral Plants:These plants flower in all photoperiods ranging from 5 hours to 24 hours continuous exposure. Some of the examples of these plants are tomato, cotton, sunflower, cucumber and certain varieties of peas and tobacco.
During recent years certain intermediate categories of plants have also been recognised. They are,
Long Short Day Plant
These are short day plants but must be exposed to long days during early periods of growth for subsequent flowering. Some of the examples of these plants are certain species of Bryophyllum.
Short-Long Day Plants:
These are long day plants but must be exposed to short days during early periods of growth for subsequent flowering. Some of the examples of these plants are certain varieties of wheat (Triticum) and rye (Secale).
Hope this helps you , if it was , plz mark brainliest
These plants require a relatively short day light period (usually 8-10 hours) and a continuous dark period of about 14-16 hours for subsequent flowering (Fig. 18.1A). Some examples of these plants which are also known as long-night-plants are Maryland Mammoth variety of tobacco (Nicotiana tabacum) Biloxi variety of Soybeans (Glycine max), Cocklebur (Xanthium pennsylvanicum).
i. In short day plants the dark period is critical and must be continuous. If this dark period is interrupted even with a brief exposure of red light (660-665 mµ wavelength), the short day plant will not flower (Fig. 18.1B).
ii. Maximum inhibition of flowering with red light occurs at about the middle of critical dark period.
(2) Long Day Plants (LDP):
These plants require a longer day light period (usually 14-16 hours) in a 24 hours cycle for subsequent flowering. Some examples of these plants which are also called as short night plants are Hyoscyamus niger (Henbane) Spinacea (spinach) Beta vulgaris (Sugar beet).
i. In long day plants the light period is critical.
ii. A brief exposure in the dark period or the prolongation of the light period stimulates flowering in long day plants.
(3) Day Neutral Plants:These plants flower in all photoperiods ranging from 5 hours to 24 hours continuous exposure. Some of the examples of these plants are tomato, cotton, sunflower, cucumber and certain varieties of peas and tobacco.
During recent years certain intermediate categories of plants have also been recognised. They are,
Long Short Day Plant
These are short day plants but must be exposed to long days during early periods of growth for subsequent flowering. Some of the examples of these plants are certain species of Bryophyllum.
Short-Long Day Plants:
These are long day plants but must be exposed to short days during early periods of growth for subsequent flowering. Some of the examples of these plants are certain varieties of wheat (Triticum) and rye (Secale).
Hope this helps you , if it was , plz mark brainliest
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