Promotion of Seedling Growth of Seeds of Rice (Oryza sativa L. cv. Hitomebore) by Treatment with H₂O₂ before Sowing

Abstract

High germinability of seeds and establishment of young seedlings in rice (Oryza sativa L.) are necessary for direct seeding in paddy fields. We investigated whether germinability and seedling growth were promoted by treatment of rice seeds (cv. Hitomebore) with hydrogen peroxide solution (H₂O₂) during the imbibition for 24 h. H₂O₂ treatment with 50 mM H₂O₂ promoted seed germination, and seedling growth (shoot length, root length and shoot fresh weight) in agar culture under a low temperature condition (18°C day/14°C night). Seedling growth was promoted by H₂O₂ treatment not only under the low-temperature condition but also under a normal (23°C day/18°C night) temperature condition. Furthermore, H₂O₂ treatment promoted seedling growth under a flooding condition in a greenhouse. These results suggest that H₂O₂ treatment of rice seeds during the imbibition is advantageous for direct seeding. We discussed the relation between the promotion of the seed germinability and the seedling growth under a low-temperature condition, and the expression of some genes encoding ROS scavenger enzymes induced by H₂O₂ treatment.