Fig. 1. Phosphorus (P), zinc (Zn), and phytic acid (PA) contents, as well as Zn bioavailability in brown rice and rice with different degrees of milling (DOM) in four doubled haploid (DH) lines. A, Synchrotron X-ray fluorescence microscopy of total P and Zn accumulation in brown rice. B and C, Concentrations of Zn (B) and PA (C) in brown rice. The same lowercase letters above bars indicate no significant differences among the four lines at the P < 0.05 level by Duncan’s multiple range test. D, Fitted curve of DOM as a function of milling duration at two stages and double-exponential decay (R2 > 0.98) for DH1. Ⅰ, Bran fraction (0% < DOM < 9%); Ⅱ, Outer endosperm fraction (9% < DOM < 15%); Ⅲ, Middle endosperm fraction (15% < DOM < 25%); Ⅳ, Core endosperm fraction (DOM > 25%). E‒G, Zn (E) and PA (F) concentrations, and the ratio of PA to Zn (G) of four lines under different DOM. The curve was fitted with an exponential one-phase decay model. The same lowercase letters indicate no significant differences among the contents at different DOM for each line at the P < 0.05 level. H and I, Zn bioaccessibility (H) and bioavailability (I) of four DH lines at different DOM. The same lowercase letters above bars indicate no significant differences at different DOM for each line at the P < 0.05 level. J, Correlations among different parameters. *, P < 0.05. Zn1, Zn bioaccessibility; Zn2, Zn uptake; Zn3, Bioavailable Zn content; PA/Zn, The ratio of PA to Zn; TZn, Total Zn levels; TP, Total phosphorus; IP, Inorganic phosphorus; Pr, Protein. Data are mean ± SD (n = 3) in B, C, and E‒I.