The distribution of saikosaponins in vegetative organs of Bupleurum scorzonerifolium Willd. (A) The pericycle (arrow) and primary phloem (arrowhead) of a 1-year-old root was stained red. (B) The phloem (arrowhead) and vascular cambium of the perennial root was stained purple red, whereas the pericycle (arrow) was stained light red. (C) The tissues of the shoot apex were stained light red. (D–F) showing the young stem, the cortex (arrow) showed dark purple red and the phloem (arrowhead) showed purple red. (G) In the mature stem, the phloem (arrowhead) was stained dark purple red. (H–I) The isobilateral leaf. (H) Structure of the blade: the palisade tissue (arrows) was stained purple red and the sponge tissue (arrowhead) showed light red. (I) The vein (arrowhead) in the blade remain unstained. (J) The control section of the root with the unstained phloem (arrowhead). Scale bars: A, B, F = 167 μm; C, I = 154 μm; D, E = 143 μm; G, H, J = 333 μm.