[Difference of root anatomy characteristics and its effect on DEHP accumulation in two genotypes of Brassica parachinensis]

Two genotypes of Brassica parachinensis, DEHP high-accumulation of Youqing-60 and low-accumulation of Teqing-60, were grown in hydroponic systems contaminated with DEHP (20 and 50 mg x L(-1)). Anatomy of roots was measured, and their effects on uptake of DEHP in roots and shoots were discussed. The results showed that roots anatomy of two genotypes of Brassica parachinensis and their responds to DEHP pollution were significantly different. DEHP contents in roots and shoots of Youqing-60 were mainly affected by the thickness of cambium in taproot and the diameter of vascular bundle, the coefficients on DEHP of roots and shoots were 0.900 and 0.809, respectively. DEHP contents of Teqing-60 were mainly affected by the thickness of cambium in taproot and cortex in fibre root in roots, which the coefficient was 0.757, and were mainly affected by the thickness of cambium in taproot in shoots, which the coefficient was 0.856. The wood ray cells in roots of Youqing-60 were rectangular shape and arranged orderly. The thickness of cork layer in taproot and cortex in fibre root of Youqing-60 were lower and the quantity of trachea and diameter of vascular bundle and trachea in fibre root of Yonqing-60 were higher than that of Teqing-60, which indicated that DEHP in soil solution and adsorbed on root were easier penetrated into xylem and transported in Youqing-60 than in Teqing-60.