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GROWTH REGULATION BY ETHYLENE IN FERN GAMETOPHYTES. IV. INVOLVEMENT OF PHOTOSYNTHESIS IN OVERCOMING ETHYLENE INHIBITION OF SPORE GERMINATION
Author(s) -
Fisher Robert W.,
Miller John H.
Publication year - 1975
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1975.tb11776.x
Subject(s) - dcmu , phytochrome , photosynthesis , ethylene , biology , spore germination , germination , botany , spore , darkness , fern , light intensity , red light , photosystem ii , biophysics , biochemistry , optics , physics , catalysis
The inhibitory effects of ethylene on spore germination were investigated. In darkness spore germination was completely inhibited by 10 μ1 · 1 −1 ethylene. Light partially overcame this inhibition, and the effect of continuous irradiation with white fluorescent light saturated at about 450 μW · cm −2 . Monochromatic red, blue and far‐red light were effective in overcoming ethylene inhibition, whereas green was not. Short periodic exposures to red or far‐red light were not sufficient to overcome ethylene inhibition. This suggested that phytochrome was not involved. The photosynthetic inhibitor DCMU blocked the effect of light. Infrared gas analysis showed that photosynthesis saturated at about 450 μW · cm −2 in white light. Red, blue and far‐red light were more efficient photosynthetically than green light; DCMU blocked photosynthesis. Normalized curves of photosynthesis and germination vs. light intensity showed a similar dependence on light energy. It was concluded that light appears to overcome the inhibitory effects of ethylene through some process dependent on photosynthesis.