A new halothermal time model describes seed germination responses to salinity across both sub- and supra-optimal temperatures

Bakhshandeh, Esmaeil; Bradford, Kent J.; Pirdashti, Hemmatollah; Vahabinia, Fatemeh; Abdellaoui, Raoudha

doi:10.1007/s11738-020-03126-9

Cited by 27 publications

(26 citation statements)

References 53 publications

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“…As suggested by Bakhshandeh et al (2020), this model was modified to the halotime model as expressed below:

{normalθ}_{Halo} = ({NaCl}_{normalb} (normalg) ‐ NaCl) {normalt}_{normalg}

where θ H is the hydrotime constant (MPa h); ψ is to the actual water potential (MPa); ψ b (g) is the base water potential [MPa, for percentage g (germination)]; θ Halo is the halotime constant (M h); NaCl is the actual NaCl concentration (M); NaCl b (g) is the base NaCl concentration (M, for percentage g); and t g is the actual time to germination percentage g (h).…”

Section: Methodsmentioning

confidence: 78%

“…3c). The NaCl b (50) values were converted to ψ b (50) values using the Van't Hoff equation to determine the osmotic adjustment value (%), as described by Bakhshandeh et al (2020). The converted ψ b (50) values (calculated using the HaloTT model) were lower (more negative) than those estimated by the HTT model in each AAP (Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…Our findings indicated that when the NaCl b (50) was converted to ψ b (50), the seeds were capable of germinating at lower ψs in all AAP as a result of osmotic adjustment (Table 1). Seeds absorb salt ions depending on their membrane permeability, and adjust their internal osmotic potentials to increase embryonic turgor and enable the seeds to germinate at lower ψs (Zhang et al 2010; Bakhshandeh et al 2020). The highest osmotic adjustment was found at AAP = 0 (14.4%), then declined linearly with AAP (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The HaloTT model suggested by Bakhshandeh et al (2020) was used for both sub‐ and supra‐optimal temperatures:

{normalθ}_{HaloTT} = ({NaCl}_{normalb} (normalg) ‐ NaCl) (T ‐ {normalT}_{normalb}) {normalt}_{normalg}

{normalθ}_{HaloTT} = [{NaCl}_{normalb} (normalg) ‐ (NaCl + {normalk}_{normalT} (T ‐ {normalT}_{normald}))] (T ‐ {normalT}_{normalb}) {normalt}_{normalg}

where θ HTT is the hydrothermal time constant (MPa °C·h), θ HaloTT is the halothermal time constant (M °C h), T d is assumed to be equal to the T o in this study, and k T is a constant indicating the positive shift in ψ b (g) and Ts > T o in the HTT model and also the negative shift in NaCl b (g) and Ts > T o in the HaloTT model.…”

Section: Methodsmentioning

confidence: 99%

“…Hydrothermal time (HTT) and halothermal time (HaloTT), as types of such models, can simultaneously determine the effects of temperature and water potential (ψ) or temperature and NaCl concentration on germination, respectively, and their parameters are highly correlated with changes in germination under natural environmental conditions. These models have been widely documented to describe germination behaviour of diverse species under both laboratory and field conditions (Alvarado & Bradford 2002; Leguizamon et al 2005; García et al 2013; Seal et al 2018; Bakhshandeh et al 2020; Liu et al 2020). They can also help us to better understand how environmental and physiological factors interact to regulate germination behaviour of seed lots (Abdellaoui et al 2019).…”

Section: Introductionmentioning

confidence: 99%

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Halothermal and hydrothermal time models describe germination responses of canola seeds to ageing

Bakhshandeh

Jamali

2021

Plant Biol J

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Hydrothermal time (HTT) and halothermal time (HaloTT) models were used to quantitatively characterize the combined effects of temperature (T), water potential (ψ) and NaCl concentration on seed germination of canola after different accelerated ageing periods (AAP) at 42 °C and 100% humidity. Seed germination time courses were observed and electrical conductivities of seed leachates were measured in all experiments. The cardinal temperatures estimated by both models were 4.6, 28 and 35 °C for the base (Tb), optimum (To) and ceiling (Tc) temperatures in water (0 MPa), respectively, when the seeds were not aged. The Tb increased with AAP, while the Tc decreased and the To remained constant at all AAP. Below To, the median base water potentials (ψb(50)) were −1.07, −0.73, −0.48 and −0.39 MPa for the AAP levels of 0, 24, 36 and 48 h, respectively. These values were more negative when germination occurred in salt solutions (the base NaCl concentrations converted to ψ were −1.25, −0.81, −0.51 and −0.41 MPa, respectively), due to uptake of salt ions. Thresholds became more positive above To and reached zero at Tc in all AAP. Seed osmotic adjustment capacity declined linearly with increasing AAP while the conductivity of seed leachates increased in association with the loss of seed vigour. Significant correlations between conductivity results and the parameters of HTT and HaloTT models suggest that they could be considered as effective descriptors of canola seed vigour.

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“…As suggested by Bakhshandeh et al (2020), this model was modified to the halotime model as expressed below: