thermal time scale

thermal time scale

[′thər·məl ′tīm ‚skāl]
(astrophysics)
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In Figure 1, the germination time courses of seeds sowed at different times (Assays I, II, III and IV) are displayed, both in clock time (graphics in the left column) and thermal time scale calculated according to the method DD1 (right column).
dubium seeds from different sources in a thermal time scale, in which the germination curves from different seed populations tend to be more clustered, suggesting little variation among thermal time requirements in different populations, since there is no reduction in seed viability along time.
The equation estimates progress in cumulative germination on a thermal time scale, and for presentation, all times to germination, [t.sub.g], were normalized on a thermal time scale by multiplying by the factor (T - [T.sub.b]) (Garcia-Huidobro et al., 1982).
The estimated [T.sub.b] values were used to normalize cumulative germination on a thermal time scale, and observed germination percentages for all temperatures were fitted reasonably well with a single germination curve (Fig.
Germination time courses at the infra-optimum temperatures were normalised on a thermal time scale (Garcia-Huidobro et al., 1982) from the parameter [T.sub.b] (base temperature) identified according to the model: probit(g) = {log [(T-[T.sub.b])[t.sub.g]]--log [theta][T.sub.50]}/ [sigma][[theta].sub.T], where probit(g) is the probit transformation of percentage g; [t.sub.g] is the time to germination of g per cent; [sigma][T.sub.50] or [mu] is the median thermal time to germination and; [sigma][[theta].sub.T] is the standard deviation (the inverse of the slope of the probit regression line).
The cumulative distribution of the isothermal germination of Ocotea pulchella seeds in the infra-optimum range on a thermal time scale shows that the progress toward germination in that range is relatively low as compared, for example, to cultivated crops (Covell et al., 1986).
These stars have now evolved rapidly on thermal time scales to higher mass and luminosity.