| Autor: |
Siegel, S. M., Gerschman, Rebeca |
| Předmět: |
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| Zdroj: |
Physiologia Plantarum; 1959, Vol. 12 Issue 2, p314-323, 10p |
| Abstrakt: |
Excised bean embryos cultured in pure oxygen show marked reductions in growth and enzyme activity, even at normal atmospheric pressure. Root and root-hair development were retarded by exposure of dry embryos to 120 atm. for 3 hrs. before culture: elongation of the main axis was not affected. Mature plants (31 species from 28 genera of Angiosperms. Pteridophytes and Bryophytes) were tested for growth-independent acute effects at 6 atm. oxygen. Exposure for 15 hrs. was generally lethal, but signs of damage were delayed in appearance as much as 24 hrs. after ending treatment. Responses include: discoloration; desiccation and withering of leaves; stem collapse; abcission (Begonia and Euphorbia especially); and recumbent stem apex. Meseuihryanthemum leaves bore droplets of exudate containing proteins and polysaccharides. Ferns are highly resistant, tolerating an oxygen tension of 10 atm., lethal to all Angiosperm species tested. Bean embryos were protected against oxygen damage by culture in 10-4 M Co(H) as measured by elongation and water uptake. Root hair development and root elongation of corn seedlings were greatly inhibited by 2 atm. oxygen, but Co(H) or cysteine at 10-5 M reduced inhibition substantially. Protection by Co(H) of pea root tips against x-radiation was compared with its similar effect in the case of oxygen poisoning. The protective effect of Co(H) and cysteine against ultraviolet radiation damage is also noted. The general biological significance of these phenomena are pointed out, especially the parallels which may be drawn between characteristics of oxygen, radiation, and thermal damage and senescent deterioration. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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