Halothermal and hydrothermal time models describe germination responses of canola seeds to ageing. (23rd April 2021)

• Record Type: Journal Article
• Authors: Bakhshandeh, E.; Jamali, M.
• Editors: Bentsink, L.
• Is Part Of: Plant biology. Volume 23:Number 4(2021)
• Page Start: 621
• Page End: 629
• Publication Date: 2021-04-23
• Subjects: Accelerated ageing period -- canola -- conductivity of seed leachates -- osmotic adjustment value -- population‐based threshold models -- seed germination; Botany -- Periodicals; Plants -- genetics -- Periodicals; Plants -- growth & development -- Periodicals; Plant Proteins -- Periodicals; Gene Expression Regulation, Plant -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1111/plb.13251
• Languages: English
• ISSNs: 1435-8603

Abstract

Abstract: 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. Abstract : Halothermal and hydrothermal time models quantified the effects of aging on canola seed germination under saline and osmotic stress.