# Why do Crypts bloom in the spring?



## HeyPK (Jan 23, 2004)

My guess is that they are short day plants, meaning that they really need a long night, since plants really measure the night length, rather than the day length. Plants have a unique pigment system. The pigments are called phytochromes, and they exist in two forms. Each form can be converted to the other. Phytochrome red (Pr) absorbs red light (optimum wavelength for absorption = 660nm) when it does absorb red light, it converts to the other form, Phytochrome far red (Pfr). This form absorbs far red light at a wavelength of 730nm). When it absorbs far red light, it gets converted back to Pr. 

During the day there is more red light than far red light, and so most of the phytochrome in a plant is in the Pfr form at the end of the day. The Pfr is the active form in plants that triggers various plant responses. During the night Pfr slowly breaks down or slowly converts to Pr. Long night plants (short day) are triggered to bloom if the Pfr drops below a certain level. If it doesn't get low enough, then the plant stays vegetative and does not bloom. Thus a short night (long day) keeps the plant vegetative. 

Short night (long day) plants are just the opposite. A high level of Pfr triggers blooming and a low level triggers vegetative growth. Thus, a short night triggers blooming, but a longer one results in vegetative growth. 

It has been found that just a short burst (a minute or two?) of red light will convert most of the Pr to Pfr. Similarly, a short burst of far red light will convert most of the Pfr to Pr. Thus, if you start the night of a long night plant with a burst of far red light, you, in effect, lengthen the night. Theoretically, you could get your crypts to bloom in the summer, if you gave them far red light for a minute or so at the beginning of each night, even if the night is short. 

I don't know how long the burst of far red has to be. I am only guessing a minute, or two. Intensity is important, too. More intense far red light will work more quickly than less intense. 

When blooming is triggered, there will be a delay until the flower is actually seen. I don't know how long that delay is in crypts.


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## Phil Edwards (Jan 22, 2004)

Has this been the majority of your experience Paul? Most of the flowers I've had have bloomed with a 12/12 photoperiod. To be fair, that was only been 6 species out of the many I had and they were all with 100% artifical light. I haven't yet tried growing them near a window or other source of natural lighting.

Serious question: Are there short/long day/night plants in the tropics? I would think that there wouldn't be enough variation in photoperiod or angle of incidence in SE Asia. I'd like to know more about this though, it could be a very useful tool.

Thanks!

~Phil


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## SCMurphy (Jan 28, 2004)

My guess would be based on typical crypt stream habitat, it would be the change from muddy water to clear water, or no water, when the rainy season subsides. The temperate change in length of day triggers the same response. Phil's plants, however, are just too pent up not to finally flower.


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## HeyPK (Jan 23, 2004)

My experience has been that most of my crypts have bloomed in the spring or fall, and they have only bloomed when they have been exposed to daylight without room lights being on to shorten the night. I have some emersed C. walkeri in a room with most of my tanks. The walkeri gets most of its light from a window, but there is enough room light after dark from the tank lights, which are set for a 16 hour day, that I never see blooming in this gallon jar of emersed walkeri. The other jar of walkeri that is blooming is on a windowsill in another part of the house where room lights are not on after dark. It is getting light only from the window. I have occasionally gotten a crypt to bloom in the fall, usually October. Again, these plants have been emersed and getting only light from the window. I have only had one crypt growing in plastic soda pop bottles bloom, a C. cordata. The rest of the crypts that have bloomed have been in glass jars. I think that the plastic is somewhat toxic and usually keeps the crypt too unhealthy to bloom. 

Long night plants (short day) only require that the night be longer than a certain length of time. If crypts bloom on a 12:12 schedule, that could mean that they bloom because the night is longer than a certain time that is less than 12 hours. Photoperiodism in the cocklebur plant has been studied a lot, and it blooms if the night is 8 hours or longer. The dark period has to be continuous. Even faint light can disrupt the long night. The only exception would be light that is far red. Ordinary room light or light from tank lights, etc. has more red light than far red, and so it converts Pr to Pfr, overall, and makes it less likely that the Pfr level will drop during the night to the required level to trigger blooming.


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