EnvReg213-page13 - In other words, a short-day plant has a...

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Plant Environmental Regulators - 13 Just in case you were wondering, the determination of short-day or long-day is not the absolute number of hours of light, but a critical number that either can not be exceeded or else must be exceeded. Both long-day and short-day plants might bloom when there is 12 hours of light. The critical thing is that a short-day plant cannot exceed “X” hours of light to flower and a long-day plant must exceed “Y” hours of light in order to flower.
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Unformatted text preview: In other words, a short-day plant has a maximum light limit, while a long-day plant has a minimum light limit. Moreover, plants are actually measuring darkness, not daylight. Interruption of the dark by even short exposures to light during the critical time period will affect flowering. • In short day (long-night) plants, the presence of Pfr inhibits flowering. • In long day (short-night) plants, the presence of Pfr promotes flowering....
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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