ISSN:
1365-3040
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract. The germination responses of a nondormant seed population of Amaranthus patulus Bertol, at constant sub-optimal temperatures in the range of 10–34°C were analysed through a detailed time-course study. Although a final germination percentage of nearly 100% was attained at temperatures above 18°C, it fell abruptly to zero with decreasing temperature from 17 to 10°C. The final germination percentage, v. temperature plotted on a normal probability scale yielded a straight line, indicating normality of the lower limit temperature within seed population with an estimated mean of 13.75°C and a standard deviation of 1.50°C. Simple linear relationships were obtained between the temperature and the germination rates, i.e., the reciprocals of the time taken to germinate by the subpopulations with 20–80% germination. The linear relationships were characterized by similar base temperatures or theoretical limit temperatures of about 11°C but there was a variation in the required ‘thermal times’ (θ), the distribution of which could be approximated for the seed population by the following distribution function:〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:01407791:PCE353:PCE_353_mu1"/〉where m is the median of the distribution and A is a parameter characterizing the pattern of the distribution. When the germination rates were calculated after subtracting 10–14 h from the time actually consumed in germination, linear Arrhenius relationships were obtained. The apparent activation energy estimated from the linear regression of Arrhenius plot was approximately 100 kJ mol−1 with all 20–80% subpopulations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/1365-3040.ep11589809
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