Infection of vascular tissues by the autoecious rusts Puccinia punctiformis and Puccinia lagenophorae: a cytological study
1992
Baka, Z.A. | Losel, D.M.
The distribution of two autoecious rust fungi within host leaves has been investigated with particular reference to the vascular system. Vascular infection by the thistle rust Puccinia punctiformis, was low at the spermogonial stage but increased during development of the uredinoid aecia. Aecial stages of P. lagenophorae were accompanied by dense fungal growth in leaf veins of Senecio vulgaris. In both cases, host cells were penetrated by unspecialized, filamentous, fungal structures. No vascular infection by the dikaryon was found in uredinial-telial phases of P. punctiformis on thistle leaves, although specialized D-haustoria were present with high frequency in mesophyll cells. These observations are consistent with the hypothesis that access to host translocates, afforded by vascular penetration, may compensate for the probably lower efficiency of the unspecialized filamentous haustoria found in spermogonial and aecial stages.
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