Letter | Published:

Reduction by Carbon Dioxide of Susceptibility of Beans to Tobacco Necrosis Viruses

Nature volume 154, pages 641642 (18 November 1944) | Download Citation



A COMPLICATING factor in the use of the local-lesion technique for estimating the concentration of plant viruses is that a standard inoculum may give widely different numbers of lesions on different leaves. Differences in age of the plant, nutrition, illumination and position of the leaf on the plant can all affect the susceptibility; but it is unknown whether they do so by altering resistance to injury during inoculation, or whether they produce more fundamental changes in the physiology of the injured cells which prevent infection. We have found that exposing plants to atmospheres containing 30–60 per cent carbon dioxide greatly reduces the susceptibility of bean plants (Phaseolus vulgaris, var. Canadian Wonder) to tobacco necrosis viruses. As this reduction can be brought about by exposure after inoculation, the effect is presumably due to physiological changes within the cell and not to the number of entry points opened during the inoculation.

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  1. 1.

    , Science, 91, 295 (1940).

  2. 2.

    , Phytopath., 33, 77 (1943).

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  1. Department of Biometry, University College, London.

    • H. KALMUS
  2. Rothamsted Experimental Station, Harpenden, Herts. Sept. 28.



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