Priming methods affected deterioration speed of primed rice seeds by regulating reactive oxygen species accumulation, seed respiration and starch degradation

Abstract

IntroductionSeed priming is a pre-sowing seed treatment that is beneficial for rice seed germination and seedling growth, but the reduced seed longevity after seed priming greatly limited its adoption. The deterioration of primed seeds showed large differences among different studies, and the priming method might play an important role in regulating the deterioration speed of primed seeds. However, whether and how the priming method affected the deterioration of primed rice seeds during storage remains unknown. MethodsIn this study, two typical seed priming methods, namely hydropriming (HP) and osmopriming (PEG) were compared under artificially accelerated aging conditions, the changes in germination performance, starch metabolism, seed respiration and reactive oxygen species accumulation before and after accelerated aging were determined.Results and discussionHydroprimed rice seeds exhibited significantly faster deterioration speed than that of PEG-primed seeds in terms of germination speed and percentage. Meanwhile, α-amylase activity and total soluble sugar content in hydroprimed seeds were reduced by 19.3% and 10.0% respectively after aging, as compared with PEG-primed seeds. Such effects were strongly associated with the increased reactive oxygen generation and lipid peroxidation, as the content of superoxide anion, hydrogen peroxide and malondialdehyde in hydroprimed seeds were 4.4%, 12.3% and 13.7% higher than those in PEG-primed seeds after aging, such effect could be attributed to the increased respiratory metabolism in hydroprimed seeds. In addition, the simultaneous use of N-acetylcysteine with HP and PEG priming greatly inhibited the deterioration of primed rice seeds, suggesting that the ability to scavenge reactive oxygen species may be the key factor affecting the speed of deterioration in primed rice seeds during storage.

Seed Hydropriming Duration for Potential Seedling Vigour in Pigeon Pea [Cajanus cajan (L.) Millsp.], Sunflower (Helianthus annuus L.) and Rice (Oryza sativa L.)

“…In the present study, priming for 12 or 24 h significantly reduced the fresh weight, dry weight of seedlings and the SVI evidenced by phenotypic expression (Fig 2). The prolonged priming was reported to lead to seed deterioration (Ren et al, 2023) which could be due to anaerobic conditions during imbibition thus reduced respiration and hence more than 7-8h hydropriming had no advantage. Furthermore, during re-drying of primed seed, the higher respiration might have used the available carbohydrates available and hence decreased growth in 24 soaking periods.…”

“…Hydropriming is the rapid uptake of water that induces partial hydration under in vitro conditions to initiate the germination process but not the protuberance of radical (Fahad et al, 2017). The priming was reported to enhance the hydrolytic enzymes like alpha-amylase activity to increase the conversion of starch to glucose for the respiration process of seed germination in cereals (Zhao et al, 2018;Ren et al, 2023), proteases (pulses) and lipases (oil seeds). Hydropriming improves the metabolism and transport of proteins, free amino acids and sugars from the endosperm to the embryo for rapid seed germination (Hussain et al, 2017) and thus improves seedling emergence and crop establishment upon sowing under field conditions (Singh et al, 2015;Mishra et al, 2017).…”

Sorghum's Survival Strategy Against Drought During Early Growth Under PEG- Simulated Conditions Based on Transcriptome Analysis

“…However, seed germination is sensitive to environmental stresses such as drought. Research indicates that seeds can respond to such stresses by adjusting energy metabolism, maintaining metabolic balance, and regulating energy storage to ensure successful germination and seedling establishment [9]. Investigating starch and sugar metabolism in sorghum germination under drought stress could offer insights to enhance drought resilience in sorghum crops.…”