Abstract
BackgroundAeration and water management increasing rhizosphere oxygen amount significantly promote rice (Oryza sativa) growth and yield, but the effect of root aeration on cadmium (Cd) toxicity and accumulation in rice seedlings under hydroponic culture remains unclear.ResultsResults showed that aeration promoted rice seedling growth and alleviated Cd toxicity. Transverse section discovered that Cd accelerated root mature and senescence while aeration delayed the mature and senescence of roots. Non-invasive Micro-test Technology (NMT) showed that aeration increased net O2 and Cd2+ influxes on the surface of roots while decreased net Cd2+ influx in xylem. Perls blue staining showed that aeration and Cd treatments increased iron plaque formation on the surface of roots. Results of metal concentration analysis showed that besides increasing Cd retention in iron plaque, aeration also increasing Cd retention in the cell wall of rice roots. Cell wall component analysis showed that aeration not only increased pectin content but also decreased pectin methylesterification degree (PMD) by increasing pectin methylesterase (PME) activity.ConclusionsAll of these results indicate that aeration not only delays root mature and senescence but also increases Cd retention in roots by enhancing iron plaque formation and regulating pectin synthesis in the roots of rice seedlings.
Highlights
Aeration and water management increasing rhizosphere oxygen amount significantly promote rice (Oryza sativa) growth and yield, but the effect of root aeration on cadmium (Cd) toxicity and accumulation in rice seedlings under hydroponic culture remains unclear
In the absence of Cd, aeration showed an obvious growth-promoting effect on rice seedlings, statistical results showed that aeration significantly increased shoot height, root length and dry weight
Intensive net Cd2+ flux was detected in xylem, less net Cd2+ flux was detected in Effects of Cd and Aeration Treatments on Iron Plaque Results of Perls blue staining showed that aeration significantly increase blue color on the surface of root tip in the absence of Cd stress
Summary
Aeration and water management increasing rhizosphere oxygen amount significantly promote rice (Oryza sativa) growth and yield, but the effect of root aeration on cadmium (Cd) toxicity and accumulation in rice seedlings under hydroponic culture remains unclear. As a highly mobile and soluble metal, Cd exposure reduces crops yield and does harm to humans’ health even at low concentrations. Cd in rice grains poses a latent health problem to humans through food chains and leads to chronic toxicity. As an export commodity, rice has posed an increasing threat to human health globally due to the contamination by Cd. it is necessary to reduce the concentration of rice Cd below the allowable level indicated by the Codex Alimentarius Commission of FAO/ WHO (CODEX 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
