The role of oxidative stress in seed priming to improve germination and vigour

Abstract

Seed priming improves germination, but responses vary with procedure and plant used, potentially from differential responses in oxidative pathways. This study targeted oxidative pathways in seed priming, using hydrogen peroxide (H2O2), antioxidant-related micronutrients (Zn, Se and Mn), or a combination, to modulate germination and plant growth characteristics of hemp and barley. Hemp tolerated higher H2O2 (1 M vs 0.125 M) and micronutrients (6-fold greater) concentrations than barley, with the combination treatment significantly increasing hemp germination but decreasing barley germination. Seed priming did not improve hemp germination under salt stress (200 mM NaCl), but the micronutrient treatment improved germination of barley under salt stress (100 mM NaCl). Histological staining showed that micronutrient-primed root tips accumulated less O2- in both non-stressed and salt-stressed conditions. We assessed seed priming benefits if grown in soil by measuring plant quality in three-week-old plants potted post-priming, but most quality factors were not significantly improved, except barley where shoot zinc content increased. In summary, seed priming with H2O2 and/or micronutrients increased germination in hemp, but only micronutrients increased barley germination. Future work will continue optimising the priming methodology and further investigate the role of oxidative stress in the observed responses.

Growth and transcriptional response of wheat and rice to the tertiary amine BMVE

“…Rapid breakdown and oxidation of nutrient reserves during seed germination results in accumulation of reactive oxygen species (ROS) that can delay or prevent seedling growth ( Kurek et al., 2019 ; Thakur and Vasudevan, 2019 ). Activation of antioxidant systems such as peroxidases (PRXs), catalases (CATs), and superoxide dismutases (SODs) facilitate ROS removal and counteract potential molecular damage ( Dietz et al., 2016 ; Steinbrecher and Leubner-Metzger, 2017 ; Noctor et al., 2018 ; Kurek et al., 2019 ; Marks et al., 2022 ). Several peroxidases (PRXs) and Cytochrome P450 genes appeared in our GO analysis results ( Supplementary Table 1 ) and these are generally known to be involved in H 2 O 2 metabolism and enhancing the activity of compounds with increased antioxidant activity ( Almagro et al., 2009 ; Pandian et al., 2020 ; Rao et al., 2020 ; Zhang et al., 2022 ).…”

“…ROS species are a detrimental by-product of these oxidation processes ( Thakur and Vasudevan, 2019 ). To facilitate seed germination, antioxidant systems are activated to scavenge free radicles ( Steinbrecher and Leubner-Metzger, 2017 ; Marks et al., 2022 ). Hence, antioxidant activity is considered a reliable indicator of robust seed germination and seedling performance ( Corbineau, 2012 ).…”