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Interchangeable effects of gibberellic acid and temperature on embryo growth, seed germination and epicotyl emergence in Ribes multiflorum ssp. sandalioticum (Grossulariaceae)
Author(s) -
Mattana E.,
Pritchard H. W.,
Porceddu M.,
Stuppy W. H.,
Bacchetta G.
Publication year - 2012
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.2011.00476.x
Subject(s) - epicotyl , biology , radicle , germination , gibberellic acid , dormancy , botany , seed dormancy , horticulture
Morphophysiological dormancy was investigated in seeds of Ribes multiflorum Kit ex Roem et Schult. ssp. sandalioticum Arrigoni, a rare mountain species endemic to Sardinia (Italy). There were no differences in imbibition rates between intact and scarified seeds, suggesting a lack of physical dormancy, while methylene blue solution (0.5%) highlighted a preferential pathway for solution entrance through the raphe. Embryos were small at seed dispersal, with an initial embryo:seed ratio (E:S) of ca . 0.2 (embryo length, ca . 0.5 mm), whereas the critical E:S ratio for germination was three times longer ( ca . 0.6). Gibberellic acid (GA 3 , 250 mg·l −1 ) and warm stratification (25 °C for 3 months) followed by low temperature (<15 °C) enhanced embryo growth rate (maximum of ca . 0.04 mm·day −1 at 10 °C) and subsequent seed germination (radicle emergence; ca . 80% at 10 °C). Low germination occurred at warmer temperatures, and cold stratification (5 °C for 3 months) induced secondary dormancy. After radicle emergence, epicotyl emergence was delayed for ca . 2 months for seeds from three different populations. Mean time of epicotyl emergence was affected by GA 3 . Seeds of this species showed non‐deep simple (root) ‐ non‐deep simple (epicotyl) morphophysiological dormancy, highlighting a high synchronisation with Mediterranean seasonality in all the investigated populations.