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Light‐Induced Fern‐Spore Germination under Reduced Water Potential
Author(s) -
Psaras G. K.,
Haupt W.
Publication year - 1989
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1989.tb00097.x
Subject(s) - spore , germination , phytochrome , peg ratio , fern , mannitol , polyethylene glycol , spore germination , chemistry , botany , sorbitol , horticulture , biophysics , biology , food science , biochemistry , red light , finance , economics
The phytochrome‐mediated spore germination of the fern Dryopteris filix‐mas was studied under reduced water content. Spores were sown on solutions containing polyethylene glycol (PEG), sorbitol, or mannitol as osmotically active substances, yielding water potential values (ψ) between − 500 and − 3500 kPa for most of the experiments. Our main results can be summarized as follows:1 The germination of the spores is completely blocked by ψ ≤ −1200 kPa (≥ 300 g/l PEG). 2 Reduced water content of the spores, at least up to 300 g/l PEG, does not impair the phototransformation of phytochrome from its inactive form P r to its active form P fr . 3 The inhibiting effect of the osmoticum is phase‐specific: the reduced water content of the spores impairs the coupling of the phytochrome system to the transduction chain. Under these conditions, P fr is found to be stable for several days. 4 In addition, the reduced water potential acts on the terminal response, although differently on different parameters of germination: Whereas formation of the rhizoid is completely blocked by 180 g/1 PEG, chlorophyll formation requires 300 g/1 PEG to become slightly retarded.