Application of the hydrotime model to assess seed priming effects on the germination of rapeseed (Brassica napus L.) in response to water stress

Abstract

Our aim was to determine whether the parameters of the hydrotime model can be used to compare the effects of seed priming treatments on germination. Seeds of three rapeseed cultivars (‘H61’, ‘H4815’, and ‘DK003’) were exposed to priming treatments and then their germination was tested at different water potentials. Seed priming improved the germination percentage, which was higher in ‘H4815’ than in the other two cultivars, and it increased germination rate (decreased θH) and uniformity (decreased σψb). The increase in germination rate was higher in PEG-osmoprimed than in NaCl-osmoprimed and hydroprimed seeds. The base water potential allowing 50% germination ([Formula: see text]) also was affected by seed priming, but the response of cultivars to different priming treatments varied. Compared with the control seeds, hydropriming of ‘H61’ seeds shifted ψb(50) toward negative values, whereas NaCl-osmopriming of ‘H4815’ seeds shifted ψb(50) toward negative values. On the other hand, priming of ‘DK003’ seeds shifted ψb(50) to more positive values and increased susceptibility to water stress. After dormancy-breaking and dormancy-induction treatments, ψb(50) shifted to more negative or positive values, indicating the release of primary dormancy and induction of dormancy, respectively. Therefore, priming treatments should be selected, depending on the environmental conditions anticipated to prevail during the germination of rapeseed seeds.

Applying population-based threshold models to quantify and improve seed quality attributes

“…However, while it is individual seeds that face the dilemma of whether to germinate now or wait until later, it is the collective action of populations of seeds that ultimately determines the success of the species or crop, whether in nature or in agricultural fields (Mitchell et al, 2017;Gremer et al, 2020). In nature, species whose seeds can more accurately predict the optimal time to germinate in their environment have a greater probability of long-term success in that environment (Larson and Funk, 2016;ten Brink et al, 2020). There are still risks involved, however, due to variability in environmental conditions, leading to bet-hedging strategies in which the seed population as a whole consists of subpopulations responding differently in variable environments (Gremer et al, 2016;Gianella et al, 2021).…”

“…The germination kinetics of primed seeds can also be characterized by HTT models Bradford and Somasco, 1994;Cheng and Bradford, 1999;Patanè et al, 2016;Tatari et al, 2020). The improvements in germination rates and uniformity are primarily due to smaller values for θ HT rather than to the lowering of ψ b (50).…”

“…Seed dormancy is a critical factor in ecological applications, where undomesticated species are being seeded into natural conditions. Native species are often exquisitely attuned to their environments, moving into and out of dormancy while in a seed bank that constitutes the future of the species (Donohue et al, 2010;Rubio de Casas et al, 2015;Finch-Savage and Footitt, 2017;ten Brink et al, 2020;Gianella et al, 2021). Successful reintroduction of species requires not only seeds from genotypes adapted to the environment of the location but also the timing of seed distribution to match seeds' expectations or requirements (Baskin and Baskin, 2020).…”

Physiological Response of Seeds of Crotalaria spectabilis under Drought and Heat Stress

“…Some substances are used to simulate water stress conditions in germination under controlled conditions, such as mannitol and polyethylene glycol (PEG 6000). During conditioning, the seeds absorb water in quantities necessary to activate the germination metabolism, however, the imbibition of the seed is stopped before the protrusion of the radicle [6].…”

Hydrotime Model Parameters Estimate Seed Vigor and Predict Seedling Emergence Performance of Astragalus sinicus under Various Environmental Conditions

“…In particular, previous studies have reported the close relationship between hydrotime model parameters and seedling emergence, and thus seed vigor, in many plant species, including alfalfa [39], cotton (Gossypium hirsutum L.) [40], rapeseed (Brassica napus L.) [41], and sugar beet (Beat vulgaris L.) [42]. It has also been reported that seed priming can increase the germination speed under water stress conditions by reducing θ H or Ψ b(g) [43][44][45][46], which implies that the change in hydrotime model parameters resulting from seed priming may be closely associated with seed vigor and the performance of seeds/seedlings in unfavorable field environments. However, to our knowledge, little literature is available concerning the description of CMV seed germination in response to water potential based on the hydrotime model, and the hypothesis that hydrotime model parameters can be applied to estimate seed vigor and predict the seedling emergence performance of forage legumes, including CMV, has not been validated.…”