淹水深度对水稻胚芽鞘伸长的影响及其生理机制OA

The screening,utilization,and investigation of the physiological mechanisms underlying anaerobic germination tolerance germplasm resources are fundamental to developing new rice varieties suitable for direct seeding.To simply and efficiently assess the anaerobic germination tolerance of germplasm resources,this study employed coleoptile length as the primary screening criterion to assess hypoxia tolerance across 432 rice accessions under 0.5(control),5.0 and 10.0 cm flooding conditions.The results showed that,under flooding stress,coleoptile length and seed survival rate exhibited substantial genetic variation,with japonica cultivars demonstrating significantly longer coleoptiles compared to indica cultivars.Ten germplasm resources with strong anaerobic germination tolerance were identified through coleoptile length and hypoxia tolerance index.Among these,the japonica rice varieties Putaohuang and Huangpinuo,as well as the indica rice varieties Esiniu and BoB,exhibited superior hypoxia resistance during germination.Additionally,the coleoptile lengths of japonica rice varieties Putaohuang and Huangpinuo were found to be longer than those of indica rice varieties Esiniu and BoB under flooding treatments.Physiological analyses revealed that the contents of abscisic acid(ABA),gibberellic acid(GA3),indole-3-acetic acid(IAA),and the activities of α-amylase(α-AMY)and alcohol dehydrogenase(ADH)were significantly higher than the control(0.5 cm)under flooding stress,and α-AMY activity,GA3 and IAA contents of japonica rice varieties were higher than that of indica rice varieties.Correlation analysis showed that under flooding treatment,the α-AMY activity,GA3 and IAA contents of four varieties were positively correlated with coleoptile length(r>0.9).The above results showed that ABA,GA3,IAA and ROS contents and α-AMY and ADH activity promote the elongation of coleoptiles,while α-AMY activity,GA3 and IAA contents play more important positive roles in the elongation of coleoptile under flooding stress,and higher α-AMY activity,GA3 and IAA contents gave japonica varieties more low-oxygen germination tolerance.