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STUDIES ON PHOTOTROPISM OF YOUNG SPORANGIOPHORES OF PILOBOLUS KLEINII *
Author(s) -
Page Robert M.,
Curry George M.
Publication year - 1966
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1966.tb05758.x
Subject(s) - phototropism , action spectrum , wavelength , pigment , optics , phycomyces , botany , biology , biophysics , blue light , chemistry , physics , organic chemistry
— Young sporangiophores of the fungus, Pilobolus kleinii , respond to unilateral illumination by bending or by growing toward light of wavelengths between 312 and 530 mμ, with peaks of sensitivity near 360 and 450 mμ. Young sporangiophores exhibit a negative phototropic response to wavelengths shorter than 300 mμ, with a strong negative response at 280 mμ. Since the action spectrum did not correspond to the absorption spectrum of the pigmented zone as measured in vivo , and since colorless sporangiophores formed on media containing diphenylamine were capable of phototropic response, it is unlikely that the conspicuous orange‐yellow pigment in young sporangiophores is the photoreceptor for phototropism. The results of probing with small beams of light and the behavior of sporangiophores submerged in mineral oil, together with measurements of the refractive index of the tip and base indicate that the photosensitive region is located in the tip of the young sporangiophore.