Figure 3.

Seedling growth of triple and quadruple mutants. Growth of WT and mutant seedlings on Zn-sufficient (Zn+) (a) and Zn-deficient (Zn−) (b) medium. Photographs were taken 8 d after germination. Bars = 1 cm. Fresh weight (c) and root length (d) of fifteen seedlings of each line grown on Zn+ or Zn− medium. Zn concentrations in shoot and roots from WT, quadruple and triple mutants grown under Zn+ (e) or Zn− (f) for eight days. Tissues were harvested, digested and analyzed by ICP-MS. (g) Zn shoot:root ratios of Zn concentrations were calculated from the data shown in panels e and f. qko indicates irt3-1/zip4-2/zip6-1/zip9-1; tko-1, irt3-1/zip4-2/zip6-1; tko-2, irt3-1/zip4-2/zip9-1. Z+S denotes shoots from Zn sufficient medium; Z+R, roots from Zn sufficiency; Z-S, shoots from Zn deficiency; Z-R, roots from Zn deficiency. Mean values and standard errors were obtained from four independent experiments. *, P < 0.05 for significant difference from WT. (h-k) Visualization of Zn localization in roots by Zinpyr-1. Confocal laser-scanning microscope images of roots of WT (h), qko (i), tko-1 (j) and tko-2 (k) stained with Zinpyr-1 and propidium iodide to visualize Zn (green) and cell walls (red), respectively. x, xylem; p, pericycle; e, endodermis; c, cortex; ep, epidermis. Bars = 50 μm.