Observations on a hitherto unreported bacterial disease the cause of which enters the plant through ordinary stomata / by Erwin F. Smith.
- Erwin Frink Smith
- Date:
- 1903
Licence: In copyright
Credit: Observations on a hitherto unreported bacterial disease the cause of which enters the plant through ordinary stomata / by Erwin F. Smith. 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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![[Reprinted from Science, N. S., Vol. XVII., No. 439, Pages 456-457, March 30, 1903.] Observations on a Hitherto Unreported Badterial Disease, the Cause of which enters the Plant through Ordinary Stomata: Dr. Erwin F. Smith, Depart- ment of Agriculture. A disease of Japanese plums of unusual interest has made its appearance in central Michigan. It is first visible in the form of numerous small water-soaked spots on the leaves and green fruits. The leaf disease ends in ‘shot-holes’; the fruit disease ends in roundish, sunken, shallow black spots and in deep fissures which spoil the plums. The spots enlarge slowly, but may finally reach a diameter of one fourth to one half inch. The disease is due to a yellow bac- terium, Pseudomonas pruni Smith, which enters the uninjured plant through ordi- nary stomata. In the earliest stage of the disease, visible only under the compound microscope in properly fixed and sectioned material, the bacteria are confined to the substomatic chamber. From this point they push into the deeper tissues, and by the time the spots have become large enough to be seen under a hand lens (as small water-soaked areas—one fifth to one half mm. in diameter), the bacteria have multiplied enormously in the depths, push- ing up the epidermis and the cells imme- diately under it, and forming in the deeper tissues closed cavities of considerable size. Later, when the enlarged spots have begun to sink in and become brown, the bacteria reach the surface as numerous tiny,](https://iiif.wellcomecollection.org/image/b22461218_0005.jp2/full/800%2C/0/default.jpg)
