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Thread: Photoperiod

  1. #1
    Tropical Fish Enthusiast jimscott's Avatar
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    We all know that temperatutes wafle up and waffle down throughout the year. We also know that day length is a curve that either goes up or goes down. What does a plant perceive when it has cloudy days on end? Is it still recognizing change in day length even there is no sunshine?

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    I'm no expert, but I would guess amount of UV radiation is what triggers it. Even on cloudy days, UV radiation is still penetrating. Also, I would guess it's not based on day to day fluctuations, but more on the order of weeks.

    I would also think there is some innate response too. I don't know - has anyone ever tried to force dormancy in July?

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    I just had to do a little research on this and found that it's actually not daylength that triggers dormancy, but night length. Shorter nights trigger growth, longer nights trigger dormancy. This makes more sense to me. In all the biology classes i ever took, I don't recall ever learning this. amazing!

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    Lauderdale's Avatar
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    I had a D.Filiformis all red that formed a hibernacula in May of last year. I put it under my grow table, cut back on water and it came back quite nicely in September. I guess it was tired of growing.
    It started dormancy in October of this year.

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