ISSN:
1618-2545
Keywords:
Bipolaris oryzae
;
Colletotrichum lagenarium
;
germ tube growth
;
infection structure
;
phototropism
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The germ tubes ofColletotrichum lagenarium showed negative phototropism to UV-blue (300–520 nm) and far-red (〉700 nm) regions with maximum in the near ultraviolet (NUV) region, while monochromatic radiations of 575–700 nm (yellow-red region) induced positive phototropism with maximum in the red region. Green light (520–575 nm) was ineffective. Negative phototropism-inducing wavelength regions inhibited germ tube growth and positive phototropism-inducing wavelength regions promoted it significantly.Bipolaris oryzae did not show any phototropic response and light did not affect the germ tube growth. These results indicate that the lens effect, in combination with the light growth reaction and light growth inhibition, is the mechanism of the phototropism of germ tubes ofC. lagenarium. NUV radiation, which induced negative phototropism ofC. lagenarium, promoted appressorium formation, while red light, which induced positive phototropism, suppressed it significantly. In the case ofB. oryzae, light did not affect the infection structure formation. These results indicate that negative phototropism of germ tubes ofC. lagenarium favors the infection process by facilitating the contact of the tips of germ tubes with the host surface, while positive phototropism has the opposite effect.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02461305
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