Summary
Flovering plants from a self-incompatible clone ofLycopersicum peruvianum were exposed during 90 days to different dose-rates of gamma-rays ranging from 2 to 17 rad perhour. Irradiation was continuous, except for a daily interruption of 7 hours.
Whereas irradiation at dose-rates higher than 7.50 rad per hour seriously inhibited bud formation and floral development, chronic exposure at dose-rates ranging from 3 to 7 rad/hour increased the number of seeds per plant. This stimulation is not due to a higher number of seeds per fruit but to a very significant rise in the number of fruits per plant. As irradiation treatment did not significantly increase the number of flowers per plant and did not appear to stimulate pollen tube germination in the styles, it is concluded that the recorded increase in fruit-setting essentially resulted from a radio-induced inhibition of the processes which control floral abscission in the absence of cross-pollination.
Three plants with reduced self-incompatibility and one completely parthenocarpic individual were observed in theM 2 progeny but no evidence was obtained that irradiation could induce a permanent type of self-compatibility inL. peruvianum.
Zusammenfassung
Blühende Pflanzen eines selbstunverträglichen Klons vonLycopersicum peruvianum wurden 90 Tage hindurch verschiedenen Dosen von Gammastrahlen ausgesetzt (2 bis 17 rad/h). Die Bestrahlungsdauer betrug täglich seiben Stunden.
Während Bestrahlungen in Dosierungen von mehr als 7,5 rad/h die Knospenbildung und Blütenentwicklung stark hemmten, steigerte eine Dauerbestrahlung mit 3 bis 7 rad/h die Samenzahl je Pflanze. Diese Erscheinung beruht nicht auf einer Zunahme der Samenzahl der einzelnen Früchte, sondern auf einer hochsignifikanten Steigerung der Fruchtzahl der einzelnen Pflanzen. Da durch die Behandlung die Blütenzahl nicht signifikant zunimmt und das Einwachsen des Pollens in den Griffel nicht gefördert wird, ist anzunehmen, daß die festgestellte Zunahme des Fruchtansatzes im wesentlichen auf eine strahleninduzierte Hemmung des Blütenverlustes bei Ausbleiben der Fremdbefruchtung zurückzuführen ist.
Drei Pflanzen mit herabgesetzter Selbstunverträglichkeit und ein vollständig parthenokarpes Exemplar wurden in derM 2-Generation angetroffen; es wurde kein Grund für die Annahme gefunden, die Bestrahlung könne eine erbliche Selbstverträglichkeit beiLycopersicum peruvianum hervorrufen.
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Literature
Brewbaker, J. L., andG. C. Emery: Incompatibility allele mutations. Genetics45, 978 (1960).
Brewbaker, J. L., andA. T. Natarajan: Centric fragments and pollen part mutation of incompatibility alleles inPetunia. Genetics45, 699–704 (1960).
Davies, D. R. andE. T. Wall: Gamma radiation and interspecific incompatibility in plants. In: Effects of ionizing radiations on seeds, IAEA symposium, Vienna (1961).
Kumar, S., andA. Hecht: Inactivation of incompatibility inOenothera organensis following U.V. irradiation. Naturwissenschaften51, 398–399 (1965).
Lewis, D.: Structure of the incompatibility gene II. Induced mutation rate. Heredity3, 339–355 (1949).
Lewis, D.: Structure of the incompatibility gene III. Types of spontaneous and induced mutation. Heredity5, 399–414 (1951).
Lewis, D., andL. K. Crowe: Structure of the incompatibility gene IV. Types of mutations inPrunus avium. Heredity8, 357–364 (1954).
Linskens, H. F., J. A. M. Schrauwen andM. van den Donk: Überwindung der Selbstinkompatibilität durch Röntgenbestrahlung des Griffels. Naturwissenschaften47, 547 (1960).
Martin, F. W.: Staining and observing pollen tubes in the style by means of fluorescence. Stain Technol.34, 125–128 (1959).
Martin, F. W.: The inheritance of self-incompatibility in hybrids ofLycopersicum esculentum Mill. xL. chilense Dun. Genetics46, 1443–1454 (1961).
McGuire, D. C., andC. M. Rick: Self incompatibility in species ofLycopersicon sect.Eriopersicon and hybrids withL. esculentum. Hilgardia23, 101–124 (1954).
de Nettancourt, D., andR. B. Contant: Comparative study of the effects of chronic gamma irradiation onLycopersicum esculentum Mill. andL. pimpinellifolium Dunal. Radiation Botany6, 545–556 (1966).
Pandey, K. K.: Mutations of the self-incompatibility gene (S) and pseudo-compatibility in angiosperms. Lloydia22, 222–234 (1959).
Pandey, K. K.: Centric chromosome fragments and pollen part mutation of the incompatibility gene inNicoliana alata. Nature206, 792–795 (1963).
Rick, R. C.: Barriers to interbreeding inLycopersicum peruvianum. Evolution17, 216–232 (1963).
Sharma, K. D., andJ. W. Boyes: Modified incompatibility of buckwheat following irradiation. Can. J. Bot.39, 1241–1246 (1961).
Swaminathan, M. S., andB. R. Murty: Effect of X-radiation on pollen tube growth and seed setting in crosses betweenNicotiana tabacum andN. rustica. Z. Vererb.-Lehre90, 393–399 (1959).
Tanaka, M.: The influence of X-irradiated pollen onNicotiana crosses. Jap. J. Breeding7, 39–44 (1957).
Yamakawa, K., andA. H. Sparrow: Correlation of interphase chromosome volume and reduction of viable seed set by chronic irradiation of 21 cultivated plants during reproductive stages. Radiation Botany5, 557–565 (1965).
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This publication is contribution no. 368 of the Euratom Biology Division.
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de Nettancourt, D., Ecochard, R. Effects of chronic irradiation upon a self-incompatible clone ofLycopersicum peruvianum . Theoret. Appl. Genetics 38, 289–293 (1968). https://doi.org/10.1007/BF01297567
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DOI: https://doi.org/10.1007/BF01297567