Action Spectrum between 250 and 800 Nanometers for the Photoinduced Inhibition of Spore Germination inPteris vittata

摘要

An action spectrum between 250 and 800 nm for the inhibition of red-light-induced germination of spores in the fernPteris vittatawas determined on the Okazaki Large Spectrograph. The resultant spectrum showed prominent peaks of effectiveness at about 370, 440 and 730 nm and a minor peak in the neighborhood of 260 nm. Next, a brief red light irradiation was given immediately after the monochromatic irradiation to cancel the inhibitory effect caused by simultaneously formed PR. This resulted in a complete disappearance of the peak at 730 nm and considerable decrease of other peaks in the shorter wavelength region except at 260 nm. Further correction of the latter spectrum by considering the transmission spectrum of a spore coat revealed that 260 nm light acted more effectively than lights of 370 and 440 nm. The inhibitory effect of UV light on spore germination was nullified by subsequent irradiation with red light for 24 h or darkness for 48 h followed by a brief red irradiation, indicating that the inhibitory action of UV light was ascribable to a blue-ultra violet light-absorbing pigment.