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Studies on Germination and Plant-Growth

Published online by Cambridge University Press:  27 March 2009

Spencer Umfreville Pickering
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Extract

Soil which has been heated without drying to temperatures from 60° to 150° behaves unfavourably towards the germination of seeds, the total seeds germinating decreasing (in most cases), and the time necessary for their germination increasing, with the temperature of heating. The average results are sufficiently regular to show that the alteration in the soil must begin at temperatures as low as about 30°.

Sterilised seeds behave in the same way as unsterilised ones, except that the time required for germination is uniformly longer. This is due to an alteration in the seeds by the sterilising agent, and not to the destruction of bacteria, for sterilised seeds do not recover their property of ready germination on being re-inoculated. Various sterilising agents were examined, but mercuric chloride was the only one found to be satisfactory and efficient.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 2 , Issue 4 , July 1908 , pp. 411 - 434
Copyright
Copyright © Cambridge University Press 1908

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References

page 412 note 1 Vol. II. p. 305.

page 412 note 2 Vol. I. p. 260.

page 415 note 1 Loc. cit. p. 322, and Nature, July 4, 1907.

page 415 note 2 Nature, June 6, and July 4.

page 417 note 1 Trans. Roy. Soc. Dublin, v(11), p 1.Google Scholar

page 430 note 1 It has also been found, in the case of the last three soils in Table XIII, that this also holds good as regards the formation of adventitious roots by trees.

page 431 note 1 In connexion with this point it may be mentioned that germination in water vapour takes place more slowly than in the presence of liquid water. Some seeds placed on a platinum gauze tray suspended over water took 2·37 and 1·07 times as long to germinate, in the case of clover and Festuca pratensis, respectively, as they did on wet paper

page 432 note 1 The additional nitrogen assimilated by the trees and plants in these experiments can be fully accounted for, so far as can be judged by the very imperfect data available, by the increase in the soluble nitrogen produced by heating. But it does not follow that these two quantities should be identical. Nitrogen is being rendered soluble during the growth of the plant, and if a plant gets a good start early in its life, owing to the richness of soil, or other circumstances, it may assimilate a greater excess of nitrogen than could be accounted for by the excess available in the soil to start with. This is certainly so in the case of trees, where the behaviour throughout life is largely conditioned by the growth when young.