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Thread: So what do they do for 3 weeks?

  1. #9
    Tropical Fish Enthusiast jimscott's Avatar
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    So maybe I ought to have gradually increased the time I had the Grolite on?

  2. #10
    Sundewist Dimka's Avatar
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    I don't think so. Its probably that the heat lasts long enough for their liking and they pop out.
    Or you can divide your seeds into 2 batches and try out both methods.
    I got a mix of seeds recently and they supposedly have a lot of different species there (I bet its just intermedia and binata judging by the look of them lol) both temperate and not. So I divided them and put one part in the fridge and another on a windowsill. I suppose in a month something will pop out
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  3. #11
    Tropical Fish Enthusiast jimscott's Avatar
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    Water temperature that the pots sit partially in is ~95 F. The Grolite is on for ~15 hours per day. That just sprouted a D. harmeyerorum. I would kill for the D. ordensis seeds to do anything! I wonder if the spatulatas, glanduligera, intermedia, and capensis would respond better than just "room temp".

  4. #12
    Sundewist Dimka's Avatar
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    On that list of yours I only grew intemedia and statulata from seeds. In my experience, they both germinate just fine with pretty much any warm conditions.
    It is hard to always be a human being... people get in the way.

    An education was a bit like a communicable sexual disease. It made you unsuitable for a lot of jobs and then you had the urge to pass it on.
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  5. #13
    Tropical Fish Enthusiast jimscott's Avatar
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    I guess I'll have to move them to the fishtank setup.

  6. #14
    Hello, I must be going... Not a Number's Avatar
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    http://www.sciencedirect.com/science...68c78f22d35132

    Seed dormancy-breaking and germination requirements of Drosera anglica, an insectivorous species of the Northern Hemisphere

    Carol C. Baskin, Milbergc, Lars Anderssond and Jerry M. Baskina

    Acta Oecologica
    Volume 22, Issue 1, January-February 2001, Pages 1-8

    Abstract

    Seeds of Drosera anglica collected in Sweden were dormant at maturity in late summer, and dormancy break occurred during cold stratification. Stratified seeds required light for germination, but light had to be given after temperatures were high enough to be favorable for germination. Seeds stratified in darkness at 5/1 C and incubated in light at 12/12 h daily temperature regimes of 15/6, 20/10 and 25/15 C germinated slower and to a significantly lower percentage at each temperature regime than those stratified in light and incubated in light. Length of the stratification period required before seeds would germinate to high percentages depended on (1) whether seeds were in light or in darkness during stratification and during the subsequent incubation period, and (2) the temperature regime during incubation. Seeds collected in 1999 germinated to 4, 24 and 92 % in light at 15/6, 20/10 and 25/15 C, respectively, after 2 weeks of stratification in light. Seeds stratified in light for 18 weeks and incubated in light at 15/6, 20/10 and 25/15 C germinated to 87, 95 and 100 %, respectively, while those stratified in darkness for 18 weeks and incubated in light germinated to 6, 82 and 91 %, respectively. Seeds collected from the same site in 1998 and 1999, stratified in light at 5/1 C and incubated in light at 15/6 C germinated to 22 and 87 %, respectively, indicating year-to-year variation in degree of dormancy. As dormancy break occurred, the minimum temperature for germination decreased. Thus, seed dormancy is broken in nature by cold stratification during winter, and by spring, seeds are capable of germinating at low habitat temperatures, if they are exposed to light.(emphasis mine)

    Quote Originally Posted by Dimka View Post
    and seeds have no photosensitive parts on the outside.
    Seed dormancy and the control of germination
    William E. Finch-Savage and Gerhard Leubner-Metzger

    http://www.seedbiology.de/pdf/Tansle...rmancy2006.pdf

    It is widely accepted that temperature regulates both dormancy and germination and that light regulates germination; however, it is a matter of debate whether light is also a regulator of dormancy (Bewley & Black, 1994; Vleeshouwers et al., 1995; Casal & Sanchez, 1998; Pons, 2000; Baskin & Baskin, 2004; Fenner & Thompson, 2005; Kucera et al., 2005). Light has been considered both to stimulate germination (e.g. Vleeshouwers et al., 1995) and to terminate dormancy (e.g. Benech-Arnold et al., 2000; Batlla et al., 2004). To some extent, this depends on where one chooses to draw the line between the processes of dormancy and germination. In this review, we have used the definition above, that dormancy is a seed characteristic that defines the conditions required for germination, and therefore any cue that widens the environmental requirements for germination should be regarded as a dormancy release factor. Following this argument, exposure to light changes the seed so that it can germinate in darkness and is therefore the last step in the dormancy-breaking process, rather than the first step in the germination process (Bewley & Black, 1994; Pons, 2000; Leubner-Metzger, 2003). This light effect (red light via phytochrome) can also be reversed in some cases by far-red light, until the seed is committed to the process of germination (Casal & Sanchez, 1998; Sanchez & Mella, 2004). In seeds with coat dormancy, it is thought that light and gibberellins (GA) can both release (coat) dormancy and promote germination (e.g. Casal & Sanchez, 1998; Leubner-Metzger & Meins, 2001; Leubner-Metzger, 2001; Sanchez & Mella, 2004; Kucera et al., 2005).
    A wide range of factors can therefore alter dormancy in PD seeds. However, there is an important distinction in the seed response to these factors. (1) There are factors that are related to slow seasonal change. These factors (e.g. temperature) are integrated over time to alter the depth of dormancy, and the sensitivity to other factors (e.g. light). (2) There are other factors that indicate in a more immediate way that conditions are suitable for germination (e.g. light), which could be considered to terminate dormancy and therefore induce germination. Each of these factors therefore removes successive blocks to germination, but this process usually needs to be carried out in a set order for it to work, i.e. in the process described light must come last to be effective. There is recent evidence from global transcriptional analysis of dormant states that the successive blocks are associated with both quantitative and qualitative changes in gene expression programmes (Cadman et al., 2006 and pers. comm.).


    See also The Seed Biology Place
    Seed Germination
    Seed Dormancy 1
    Seed Dormancy 2
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  7. #15
    Sundewist Dimka's Avatar
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    Cool. I still don't get how light affects them. Seed shell has no photosensitive parts, so how does it improve germination? Who knows? Maybe its like a microwave effect or something?
    Its interesting... I think I'll take botany sometime just out of interest... when I see the light in my educational tunnel
    It is hard to always be a human being... people get in the way.

    An education was a bit like a communicable sexual disease. It made you unsuitable for a lot of jobs and then you had the urge to pass it on.
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  8. #16
    Tropical Fish Enthusiast jimscott's Avatar
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    Thanks for providing that article. Now, D. anglica is a temperate, right? What about species that are triopical in nature? Do they need some sort of cold and wet period first?

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