Crown gall of plants.

  • Erwin Frink Smith
Date:
[1911]
Catalogue details

Licence: In copyright

Credit: Crown gall of plants. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    APPLE HAIRY ROOT This disease supposed to be distinct from crown gall and non-infec- tious we have also proved to be due to bacteria scarcely distinguish- able from those occurring in ordinary crown gall. These bacteria are found in the nodular base from which the tufted clusters of roots arise. We kave induced the disease by pure culture inoculation not only in the apple but also in other plants and the disease would seem to belong with crown gall as only a special form of the latter. As a tentative hypothesis until further experiments are made we may as- sume either : (1) That the hairy root organism while resembling the crown gall organism is not identical with it ; or (2) that they are the same, and if infection takes place in a certain group of cells an ordi- nary gall will develop, while if other special groups of cells are first invaded, i. e. root anlage, then a cluster of the fleshy roots will develop. Some of our inoculation experiments point to the latter conclusion. NATURE OF THE GALL Superficially these growths are like those due to various fungi, to gall insects, to Plasmodiophora brassicae, or to the olive-tubercle or- ganism, but structurally they are different. Their manner of growth and their histology strongly suggest certain malignant animal tumors. The writer has twice called attention to this publicly at meetings of the American Society for Cancer Research (first in 1909) and has summarized the evidence somewhat carefully in the bulletin referred to. More recently (October, 1910) Jensen of Denmark has expressed similar views respecting the crown gall of the sugar-beet, but without knowing of our results. One of the principal biological problems of today, and one of the most interesting in the whole range of pathology, is to determine if possible the chemical stimulus responsible for overgrowths. This problem is of immense and wide-reaching importance not only to the pathologist but also to the physiologist and all others interested in cell mechanics. In conclusion I may be permitted to express the hope that in these plant tumors, now so easily producible by a definite mi- croorganism, we possess means of determining the cause of cell divi- sion and possibly of shedding some light on the origin of certain ma- lignant animal tumors. Note.—Massee has recently claimed to confirm Tourney’s finding of Dendro- phagus in crown gall of rose and chrysanthemum (Kew Bulletin No. 9, 1910). He also notes that he could find no trace of B. tumefaciens. The last statement is not surprising, and the first one appears to rest on no better evidence than a some- what hasty microscopic examination, without attempt at pure cultures or inocula- tions. Such a microscopic examination, even if it were a very long and careful
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