Figure 3.

Scanning electron microscopy showing the root xylem vessels of susceptible and tolerant soybean cultivars when inoculated with P. sojae. (A) Vascular cylinder of the non-infected susceptible soybean cultivar, (B) Vascular cylinder of the infected susceptible soybean cultivar, (C) Vascular cylinder of the non-infected tolerant soybean cultivar, (D) Vascular cylinder of the infected tolerant soybean cultivar. The root of susceptible cultivar contains small vascular cylinder while the root of tolerant cultivar contains large vascular cylinder, denoted by red arrows. White arrows denote the presence of hyphae within the vascular cylinder and yellow arrows denote the presence of vermiculite. Bars: (A–D) 80 µm.