ABSTRACT.
Effect of ultrasonic seed treatment on rice seedlings under waterlogging stress

Suihua Huang1, 2, Yuanyuan Jia1, Ping Liu1, Hao Dong1, and Xiangru Tang1, 2*
 
One of the main problems of rice (Oryza sativa L.) cultivation is erratic germination and crop establishment; therefore, a pre-sowing ultrasonic seed treatment was studied to improve this situation. A pot experiment was conducted to investigate the effect of ultrasonic seed treatment on rice seedlings under waterlogging conditions. Two cultivars of rice seeds, 'Yuejingsimiao' (YJSM) and 'Yuxiangyouzhan' (YXYZ), were treated with ultrasonic waves before being transferred to the pot. The ultrasonic treatment included seed treatments in the dry state (S1), wet state (S2), and a control (CK). The waterlogging treatment included three flooding levels, control (W0), 2.0-3.0 cm flooding (W1), and 3.0-4.0 cm flooding (W2). The seedling emergence rate for W1S2 was 35.07% to 64.39% higher than W1CK, while fresh weight for W2S2 increased by 54.21% to 89.98% compared with W2CK. Furthermore, W1S1 (11.74% to 15.02%) and W1S2 (7.87% to 43.29%) also increased catalase activities compared with W1CK. Malondialdehyde (MDA) decreased by 19.87% to 31.84% and 9.70% to 38.74% for YJSM and YXYZ, respectively. The results showed that under waterlogging conditions, wet seed under ultrasonic treatment significantly increased the seedling emergence rate. Both the wet and dry seed treatments improved seedling quality, antioxidant activity, but decreased the MDA content.
Keywords: Antioxidants, germination, flooding condition, Oryza sativa, ultrasound.
1South China Agricultural University, College of Agriculture, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou, 510642, China.2Ministry of Agriculture and Rural Affairs, Scientific Observing and Experimental Station of Crop Cultivation in South China, Guangzhou, 510642, PR China. *Corresponding author (tangxr@scau.edu.cn).