Enhancement in rice seed germination via improved respiratory metabolism under chilling stress

Chilling stress is one of the abiotic stresses that severely limited the production of many field crops. The chilling stress during emergence stages of rice severely hampered the process of seed germination and seedling growth and resulted in yield losses. Meanwhile, the development of seed priming has been proved to effectively enhance the seedling establishment of rice under chilling stress. However, the regulating effects of seed priming on the respiratory metabolism during rice seed germination under chilling stress have rarely been explored. In the present study, the effects of two pre-optimized seed priming treatments, selenium priming (Se) and salicylic priming (SA), were examined under chilling stress. The results revealed that chilling stress significantly reduced the rice seed germination and seedling growth, as well as the respiration rate and ATP contents in rice seeds and seedlings. While seed priming was effective to significantly enhance the respiration rate and ATP levels in rice seeds and seedlings, such positive effects might be induced by the enhanced glycolysis metabolism, as well as the repair and biogenesis of mitochondria. However, the molecular mechanisms in association with the enhanced respiration in primed rice seeds and seedlings under chilling stress still needed to be addressed in future studies.