Roots of lin become infected by rhizobia at lower than normal rates and form nodule primordia (C) but all infections are arrested in the root epidermis (A and B). Mycorrhizal infections of lin are normal (D) . A, B and C. Roots inoculated with Sinorhizobium meliloti. D. Roots inoculated with Glomus versiforme, showing arbuscule formation in the inner root cortex.
Figures A , B and C courtesy of Doug Cook and Varma Penmetsa. Figure D from Maria Harrison.