Photoperiodism in plants Photoperiodism in plants Photoperiodism the

Photoperiodism in plants

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod).

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod). Long-day plants (LDP): - Only flower when the photoperiod exceeds a certain value, known as critical day length (CDL).

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod). Long-day plants (LDP): - Only flower when the photoperiod exceeds a certain value, known as critical day length (CDL). - Does not have to be longer than 12 hours.

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod). Long-day plants (LDP): - Only flower when the photoperiod exceeds a certain value, known as critical day length (CDL). - Does not have to be longer than 12 hours. - Characteristic of higher altitudes, where seasonal variation in daylength is greater.

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod). Long-day plants (LDP): - Only flower when the photoperiod exceeds a certain value, known as critical day length (CDL). - Does not have to be longer than 12 hours. - Characteristic of higher altitudes, where seasonal variation in daylength is greater. - LDP’s begin to flower when the days are lengthening, in spring and early summer – if transplanted to the tropics, it may not flower because the days aren’t long enough.

Photoperiodism in plants Photoperiodism – the regulation of seasonal activity by daylength (photoperiod). Long-day plants (LDP): - Only flower when the photoperiod exceeds a certain value, known as critical day length (CDL). - Does not have to be longer than 12 hours. - Characteristic of higher altitudes, where seasonal variation in daylength is greater. - LDP’s begin to flower when the days are lengthening, in spring and early summer – if transplanted to the tropics, it may not flower because the days aren’t long enough. - EG – Temperate grasses, snapdragons, radish and lettuce

Photoperiodism in plants Short-day plants (SDP) - Only flower when the photoperiod is less than the CDL.

Photoperiodism in plants Short-day plants (SDP) - Only flower when the photoperiod is less than the CDL. - Many native tropical species are SDP’s even though the daylength may not vary more than two hours during the year.

Photoperiodism in plants Short-day plants (SDP) - Only flower when the photoperiod is less than the CDL. - Many native tropical species are SDP’s even though the daylength may not vary more than two hours during the year. - EG – Maize and sugar cane.

Photoperiodism in plants Short-day plants (SDP) - Only flower when the photoperiod is less than the CDL. - Many native tropical species are SDP’s even though the daylength may not vary more than two hours during the year. - EG – Maize and sugar cane. Day-neutral plants - Are not affected by photoperiod - EG – dandelion, tomato, and garden pea.

Photoperiodism in plants Short-day plants (SDP) - Only flower when the photoperiod is less than the CDL. - Many native tropical species are SDP’s even though the daylength may not vary more than two hours during the year. - EG – Maize and sugar cane. Day-neutral plants - Are not affected by photoperiod - EG – dandelion, tomato, and garden pea. ** Over-simplification. Photoperiod can be affected by plant age, temp and nutrient availability.