Soil microalgae modulate grain arsenic accumulation by reducing dimethylarsinic acid and enhancing nutrient uptake in rice (Oryza sativa L.)
Background and aims
Microalgae are ubiquitous in paddy soils. However, their roles in arsenic (As) accumulation and transport in rice plants remains unknown.
Two green algae and five cyanobacteria were used in pot experiments under continuously flooded conditions to ascertain whether a microalgal inoculation could influence rice growth and rice grain As accumulation in plants grown in As-contaminated soils.
The microalgal inoculation greatly enhanced nutrient uptake and rice growth. The presence of representative microalga Anabaena azotica did not significantly differ the grain inorganic As concentrations but remarkably decreased the rice root and grain DMA concentrations. The translocation of As from roots to grains was also markedly decreased by rice inoculated with A. azotica. This subsequently led to a decrease in the total As concentration in rice grains.
The results of the study indicate that the microalgal inoculation had a strong influence on soil pH, soil As speciation, and soil nutrient bioavailability, which significantly affected the rice growth, nutrient uptake, and As accumulation and translocation in rice plants. The results suggest that algae inoculation can be an effective strategy for improving nutrient uptake and reducing As translocation from roots to grains by rice grown in As-contaminated paddy soils.
KeywordsArsenic Oryza sativa Microalga Soil remediation Paddy soil
This research is supported by the National Natural Science Foundation of China (41701373, 31772197) and China Postdoctoral Science Foundation funded project (2017 M621667). The authors are grateful to Associate Professor Gaoling Shi in Jiangsu Academy of Agricultural Sciences and Dr. Yong-He Han in the Fujian Normal University for their constructive suggestions in manuscript preparation. We also thank Dr. Shuo Liu and Jiali Yan in State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University for providing rice seed.
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