Interchangeable effects of gibberellic acid and temperature on embryo growth, seed germination and epicotyl emergence in Ribes multiflorum ssp. sandalioticum (Grossulariaceae)

Abstract

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.

Seed dormancy and germination in three Crocus ser. Verni species (Iridaceae): implications for evolution of dormancy within the genus

“…The most favourable period for seedling establishment can vary according to the geographic distribution, climate conditions, habitat preference and life cycle of the species (Nikolaeva 1999;Mattana et al 2012;Vranckx & Vandelook 2012). This variation is often reflected in different seed behaviour, including seed dormancy, which helps to prevent germination at times when environmental conditions are unfavourable for subsequent seedling establishment (Vleeshouwers et al 1995;Baskin & Baskin 1998;Finch-Savage & Leubner-Metzger 2006).…”

The role of GA3in the germination process of high-mountain endemic and threatened species:Leontopodium nivalePinguicula fioriiandSoldanella minimasubsp.samnitica(central Apennines, Italy)

“…For the germination trials, two replicates with 25 seeds in each Petri dish were set up for each parameter to be tested, due to the small sizes of the populations (Cerabolini et al 2004;Mattana et al 2012aMattana et al , 2012bMattana et al , 2012cCarta et al 2013). The seeds were soaked for 24 h in demineralised water and then sterilised with 1% NaClO (1 min for S. minima subsp.…”

“…The treatment of seeds with this substance prior to incubation in growth chambers is a technique widely used in the laboratory for the propagation of many species. Gibberellic acid (GA 3 ) can enhance the embryo growth, increment the germination rate and favour seed germination in a wide range of temperatures (Mattana et al 2012a(Mattana et al , 2012b(Mattana et al , 2012c. It can also interrupt seed dormancy and promote seed germination in harsh conditions, such as in the presence of salt in the substrate (Atia et al 2009;Alberto et al 2011;Camas & Caliskan 2011).…”

“…Dormancy is a strategy that has been developed in many species to make sure that germination occurs during the most favourable period for the survival and development of the seedlings, to ensure the reproductive success of the species (Baskin & Baskin 1998). This strategy has been documented for several high-altitude species (Giménez-Benavides et al 2005;Jurado & Flores 2009;Schwienbacher et al 2011;Mattana et al 2012aMattana et al , 2012bMattana et al , 2012c.…”

Gibberellic Acid Induces Asymbiotic Germination of the Obligate MycoheterotrophPterospora andromedea(Ericaceae)

“…The importance of gibberellins (GAs) and their activity as promoters of seed germination is well documented in model systems (Koornneef et al 2002;Sun and Gubler 2004). GA has been applied to many non-model plants for conser-vation (Li et al 2007;Ortega-Baes and Rojas-Aréchiga 2007;Flores et al 2008;Zeinalabedini et al 2009;Mattana et al 2012;Kandari et al 2012) and restoration (Commander et al 2009;Turner et al 2012). However, the efficacy of GA on monotrope germination has not been examined.…”