摘要
Waterlogging is frequently stressed rapeseed growth. Under this stress, plant is in state of hypoxia which limits aerobic respiration and energy metabolism. Promoting root growth is an adaptive strategy of terrestrial plants in response to waterlogging stress. Auxin plays important roles in root growth. However, the effects of auxin on rapeseed root growth under waterlogging stress remain largely unknown. In this study, we investigated endoge-nous IAA levels and root growth of rapeseed under hypoxia stress （H）, hypoxia treatment with IAA（HI）f PCIB （an auxin action inhibitor, HP） or TIBA（an auxin polar-transport inhibi-tor, HT） through hydroponic experiment. Pot experiment was further employed to evaluate effects of exogenous IAA on growth of rapeseed under waterlogging stress by foliar spray-ing. Results from hydroponic showed that compared with control （CK）, hypoxia significantly decreased rapeseed growth after 48 hours treatment, while HI dramatically alleviated the depression. In contrast, HP and HT aggravated growth depression by hypoxia stress, as indicated by obvious decrease in root and shoot dry weight. Under hypoxia stress, alter-ation in root growth, especially for lateral roots with a diameter 〈1.5 mm was positively related with IAA levels in roots. Pot experiment further proved those findings. These results suggested that endogenous IAA might be involved in root growth of rapeseed response to waterlogging stress. Furthermore, foliar spraying with moderate IAA increased rapeseed growth underwaterlogging stress through promoting endogenous lAA-caused root growth. This work provided an available method to improve rapeseed tolerance to waterlogging in soil.
