Skip to main content
. 2018 Apr 25;9:552. doi: 10.3389/fpls.2018.00552

FIGURE 2.

FIGURE 2

Light micrographs of sections showing the successive developmental stages of D. officinale from seed germination to protocorm formation in symbiotic culture. (A) Stage 0, the uncolonized embryo covered by a thin seed coat in the first week of inoculation. The embryo cells filled with storage products, such as protein and lipid bodies. Scale bar = 50 μm. (B) Stage 1, the infected embryo after 1 week of inoculation. Fungal hyphae have colonized the embryo and formed the pelotons (arrows) within embryo cells. Larger vacuoles make the embryo cells expand and the storage nutrients disappear from most embryo cells. Scale bar = 50 μm. (C) Stage 2, the enlarged embryo with the rupture of the seed coat after 2 weeks of inoculation. The pelotons (arrows) locate in outer cortical cells and inner cortical cells of the spherical protocorm. Scale bar = 50 μm. (D) Stage3, protocorm with the first crest and rhizoids after 3 weeks of inoculation. At this stage, the pelotons (arrows) are digested in the inner cortical cells. c, crest; r, rhizoid. Scale bar = 100 μm.