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Titolo:
SPECIFIC TROPISM CAUSED BY ULTRAVIOLET-C RADIATION IN PHYCOMYCES
Autore:
MARTINROJAS V; GREINER H; WAGNER T; FUKSHANSKY L; CERDAOLMEDO E;
Indirizzi:
UNIV SEVILLA,DEPT GENET,APARTADO 1095 E-41080 SEVILLE SPAIN UNIV SEVILLA,DEPT GENET E-41080 SEVILLE SPAIN UNIV FREIBURG,INST BIOL 2 D-79104 FREIBURG GERMANY
Titolo Testata:
Planta
fascicolo: 1, volume: 197, anno: 1995,
pagine: 63 - 68
SICI:
0032-0935(1995)197:1<63:STCBUR>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOTROPISM; STIMULUS;
Keywords:
BLUE LIGHT; GALLIC ACID; PHYCOMYCES (UVI MUTANTS); TROPISM; ULTRAVIOLET-C RADIATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
V. Martinrojas et al., "SPECIFIC TROPISM CAUSED BY ULTRAVIOLET-C RADIATION IN PHYCOMYCES", Planta, 197(1), 1995, pp. 63-68

Abstract

The giant sporangiophores of Phycomyces blakesleeanus turn towards blue and away from ultraviolet C sources (wavelength under 310 nm). We have isolated fifteen mutants with normal blue tropism but defective ultraviolet tropism. Wild-type sporangiophores described a double turn when exposed successively to blue and ultraviolet beams coming from thesame side; under certain conditions, the mutants turned only to the blue. The new uvi mutations modified the behaviour in heterokaryosis and were lethal in homokaryosis, i.e., they affected essential cellular components. The responses of the wild type and one of the mutants wereregistered and evaluated with a computer-aided device. The mutant behaved normally under blue light, but took longer than the wild type to turn away from the ultraviolet source. With very weak ultraviolet stimuli (10(-8) and 10(-9) W . m(-2)), the wild type turned towards the source, but the mutant did not respond. Calculations of absorbed-energy distributions in the sporangiophore showed that Phycomyces responds differently to similar spatial distributions of blue and ultraviolet radiations. Wild-type and mutant sporangiophores had the same high ultraviolet absorption due to gallic acid. We conclude that ultraviolet tropism is not just a modification of blue phototropism due to the high ultraviolet absorption of the sporangiophores. Phycomyces has a separatesensory system responsive to ultraviolet radiation, but not to blue light.

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Documento generato il 30/09/20 alle ore 05:52:42