Experiment Station Record, Volume 92, January-June, 1945 Page: 64
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64 EXPERIMENT STATION RECORD [Vol. 92
nity may be considered a type of "passive immunization." By using Turkish tobacco
it became possible by graft transfer to immunize tomato plants against individual
virus strains. Clonal plants propagated from the immunized tomato plants
exhibited a wide variation in response, depending on the virus strain used and
ranging from vigorous, at times symptomless, plants to a condition of low vigor
and conspicuous curly top symptoms. Tomato clones immunized by single strains
of the virus, when tested by reinoculation superimposing different virus strains,
showed a high degree of protection against some strains and less against others.
These reactions indicated a definite specificity of immunization similar to known
reactions from animal viruses. This study has manifested the following phenomena:
Regularly occurring recovery in tobacco; acquired resistance of recovered plants to
injury from reinoculation; persistence in recovered plants of curly top virus not
lessened in virulence; evidence of a time factor in the reactions leading to recovery
and that this recovery and acquired resistance does not result from invasion of
embryonic tissues; proof of transfer by grafting of this condition of acquired
immunity from a recovered plant, not only as an intraspecific transfer (tobacco to
tobacco) but also as an? interspecific passage (tobacco to tomato varieties that rarely
initiate the recovery reaction); and, finally, evidence of a striking specificity exhibited
by different strains of the virus. This whole range of evidence indicates the
phenomena to be immunologic in nature.
Notes on seed-borne fungi.-I, Stemphylium, J. W. GROVES and A. J. SKOLKO
(Canad. Jour. Res., 22 (1944), No. 4, Sect. C, pp. 190-199, illus. 11).--Three
species isolated from agricultural seeds are described and illustrated, viz, S. sarcinaeforme,
S. botryosum, and S. consortiale n. comb. The first was found only on red
clover seeds; the other two, on a wide variety of seeds. The perfect stage of
S. botryosum is Pleospora herbarum,; that of the other two is unknown.
Cuscuta japonica Choisy, an Asiatic species new to America, T. G. YUNCKER
(Torreya, 44 (1944), No. 2, pp. 34-35).-Until recently, there have been only four
foreign species of dodder of economic significance known to have been introduced
into the United States. Specimens of a fifth species-C. japonica-have been received
by the author from Texas and Florida, in both cases on kudzu. From
notes accompanying the Florida material it seems apparent that this species will
be able to parasitize native American plants'; there is little doubt but that it would
spread if allowed to become established in a favorable environment.
Estudos sobre a transmissao experimental da "clorose infecciosa" das
Malvaceas (Studies on the experimental transmission of the "infectious
chlorosis" of Malvaceae), K. SILBERSCHMIDT (Arq. Inst. Biol. [Sao Paulo], 14
(1943), pp. 105-156, illus. 14; Eng. abs., pp. 153-154).-The results are given of
observations and experiments on the transfer of the virus disease of Sida acuta
carpinifolia, S. rhombifolia, and S. cordifolia, and of two ornamental shrubs,
Abutilon striatum and A. striatum spuriurn. In the tests recorded, transmission by
seed or sap inoculation was unsuccessful with Sida; in graft unions, however, the
virus passed easily from diseased to healthy component, infection was carried more
rapidly in basipetal than in acropetal directions, and a union of only 2 days was sufficient
to permit passage of the virus from diseased to healthy component. Submitting
the infected scion to high temperatures before grafting delayed the
appearance of symptoms in the stock. In interspecific grafts, healthy stock of
S. rhombifolia became infected easily from diseased scions of all three species of
Sida; but stocks of S. acuta exhibited more severe symptoms after being infected
from the same species than from S. rhombifolia; similar differences were noted
with the reverse type of graft. In intergeneric grafts, diseased scions of A. spurium
carried the typical disease to stocks of S. rhombifolia, but only extremely
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5064/m1/77/: accessed March 25, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.