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Upward translocation of acetochlor and atrazine in wheat plants depends on their distribution in roots

Ju, Chao, Zhang, Hongchao, Wu, Ruilin, Dong, Suxia, Yao, Shijie, Wang, Feiyan, Cao, Duantao, Xu, Shiji, Fang, Hua, Yu, Yunlong
The Science of the total environment 2020 v.703 pp. 135636
Triticum, Zea mays, acetochlor, apoplast, atrazine, bioaccumulation, cell walls, corn, herbicide residues, hydroponics, leaves, lipids, models, organelles, product safety, roots, soil, stems, symplast, wheat
Residual acetochlor and atrazine in soils, resulting from their extensive application to maize plants, may affect product safety of the ultimate wheat crop. To determine the potential uptake and accumulation of acetochlor and atrazine by wheat plants, the uptake mechanism, translocation, and subcellular distribution of these two herbicides were studied through hydroponic experiments (10 mg L⁻¹). The results indicated that acetochlor can be taken up through the apoplastic pathway and can accumulate in wheat roots with little upward translocation. However, atrazine could be taken up by roots through the symplastic pathway and subsequently transported to the stems and leaves. Little upward translocation of acetochlor in wheat plants was due to its preferential distribution into root organelles with higher lipid contents. Conversely, the low bioconcentration of atrazine in root organelles and cell walls after uptake led to its easy upward translocation. Uptake of acetochlor and atrazine by wheat roots and the distribution of atrazine to the stems and leaves were predicted well by using the partition-limited model. The obtained results indicated that residual atrazine in soil may be taken up by wheat roots and acropetally translocated, thereby posing a threat to product safety of wheat.