Increasing Germination Rates

Sorry this is a bit long, I wanted to avoid being confusing by skipping to many details. It all leads to an experiment I�m planning on a potential way to increase germination rates in cannabis seeds.

Seed germination is controlled by a number of factors, such as temperature, moisture, and time. These factors are commonly accounted for and altered according to the species, or even strain, to maximize germination of the most seeds. However, the wavelength of light exposed to the seed prior to darkness is not commonly regulated, and this may be able to make a huge difference.

The way it works:
Phytochromes are receptor molecules found in the cells of all higher plants. These receptors absorb light from the red and far-red region of the light spectrum, and control a variety of responses in flowering plants. These responses include, but is not limited to, seed germination; seedling elongation; size, shape, and number of leaves; photoperiodism; and synthesis of chlorophyll.
(In a bit more optional detail: The phytochrome molecule can occur in two different molecular shapes. One molecular shape for the phytochrome is Pr. When in this shape it can absorb red light, which changes the molecular shape to Pfr. When in the Pfr form it is able to absorb far-red light, which will change it back to the Pr shape. The Pfr shape is the only one that is biologically active: That is, it�s the only one that induces the listed responses. Therefore, to induce the responses, one should expose the phytochromes to red light.)

Before even this much was known (and this is still not a fully understood process) the following occurred:

Experiments were performed by the USDA on the effects of red light on seed germination. They used lettuce seeds that had been soaked in water. Each group of seeds was then subject to a different set of light treatments, then allowed to germinate in the dark. The actual experiment used a number of different groups, but for this briefer explanation I will only discuss a couple (the rest reinforce the same observation).

The control group was allowed to germinate in the dark, with the following results:

http://www.fullmeltbubble.com/galler...dark_thumb.jpg

Another group was exposed to a flash of red light, then straight to darkness for the remainder of time. These results were considerably more impressive:

http://www.fullmeltbubble.com/galler...dark_thumb.jpg

Both groups were given the same amount of time to germinate. The only difference between the two is that the second group was exposed to a flash of red light before being put in the dark.

(More information on phytochrome research is available here (seed germination is just the tip of the iceberg, and there are many more great sites with information on this topic): http://www.ars.usda.gov/is/timeline/light.htm?pf=1 )

Personally, when I first heard about this I wondered why red light hitting a seed directly before dark would increase germination rates, and what factors in nature had created a competitive advantage to seeds possessing this trait. My speculative conclusion is derived as follows: Two of the most important factors in a seedlings survival is that it is close enough to the surface of the soil, and that it will receive enough sunlight once it has sprouted to grow into an adult form. On earth sunset is a time of day that has proportionally more red light than the rest of the day, and is followed by dark. By the red light from sunset hitting the seeds it encourages growth of seedlings that are not deeply buried in soil, and the fact that the seedling is receiving sunlight during sunset means that it is more likely (though still not guaranteed) to be in an area where it will receive adequate sunlight to grow and flourish. This paragraph is my personal theory on the evolutionary aspects of this trait, but to return to the original topic,

The way the phytochromes function in plants is absolutely incredible. Just one wavelength being absorbed by one phytochrome induces a cascade of reactions that ultimately, through gene expression regulation, can be amplified to the production of hundreds of �secondary messenger molecules.� It is because of this that it only requires a brief exposure to red light to induce germination.

This sounds like a potentially great method to increase germination. I�m currently planning my own parallel experiment to test this on cannabis seeds. Will definitely post pictures as I go.

It'd be great to hear others thoughts about this.

MI

this sounds like epigenetics-something i am learning about on another board. epigenetics, as i understand, is the way an adverse environment will induce an altering of the genetics of a plant to compensate for the environment. survival of the fittest where the fittest have genes they pass to their progeny that will make the future generations more and more tolerant of their environment. survival of the fittest....(evolution?).
i think your paragraph is wonderfully stimulating. i find popping beans to be very nerve wracking lol. when you're perpetually poor (as i tend to be) every bean counts in the quest. im hi and i think there was something else i was going to say so i be back!
great thread and welcome to fullmelt!
pwf

This is absolutely a form of epigenetics. Epigenetics goes beyond environmental adaptation. It can be thought of as the genetics that aren't directly coded for in our DNA. If you consider genetics as the DNA sequence that becomes proteins, epigenetics is all of the factors that control which DNA sequences are becoming which proteins. In this case, the activation of phytochromes is being used to induce the response of germination. Phytochromes do different things in different plants, parts of plants, and at different stages of development.

Survival of the fittest is a phrase used to describe natural selection, Darwin's proposed theory on a mechanism of evolution. Evolution is an observable phenomenon (no one disputes the evolution of new dog breeds or cannabis strains), for which a number of mechanisms are known and theorized.

Increasing germination rates is ultimately valuable to all smokers. The more seeds that germinate into plants, the more genetic variation and distinct phenotypes that can be found in any batch of viable seeds with a less than perfect germination rate.

Looking forward to having more to show (results!) in the near future.

MI

Really interesting read, cant wait for your experiments on this matter. As pwf stated, with us poor folks we need every bean to germ that we can. Looking forward to updates and pics soon!