Host-Parasite Relationship in a Susceptible and a Resistant Rose Cultivar Inoculated with Sphaerotheca pannosa.

II. Deposition Rates of Callose, Lignin and Phenolics in Infected or Wounded Cells and their Possible Role in Resistance

Authors

  • G. G. Conti,

    Corresponding author
    1. Istituto di Patologia Vegetale, Università di Milano, Italy Istituto di Botanica, Università di Parma, Italy Gruppo Virus e Virosi delle Piante, CNR, Unità di Ricerca di Milano, Italy
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  • M. Bassi,

    Corresponding author
    1. Istituto di Patologia Vegetale, Università di Milano, Italy Istituto di Botanica, Università di Parma, Italy Gruppo Virus e Virosi delle Piante, CNR, Unità di Ricerca di Milano, Italy
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  • D. Maffi,

    Corresponding author
    1. Istituto di Patologia Vegetale, Università di Milano, Italy Istituto di Botanica, Università di Parma, Italy Gruppo Virus e Virosi delle Piante, CNR, Unità di Ricerca di Milano, Italy
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  • A. M. Bocci

    Corresponding author
    1. Istituto di Patologia Vegetale, Università di Milano, Italy Istituto di Botanica, Università di Parma, Italy Gruppo Virus e Virosi delle Piante, CNR, Unità di Ricerca di Milano, Italy
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  • With 15 figures

Authors' addresses: G. G. Conti, Istituto di Patologia Vegetale, Via Celoria 2, 20133 Milano (Italy).

M. Bassi, Istituto di Botanica, Via Farini 90, 43100 Parma (Italy).

D. Maffi, Istituto di Patologia Vegetale, Via Celoria 2, 20133 Milano (Italy).

A. M. Bocci, Gruppo Virus e Virosi delle Piante, C.N.R., Unità di Ricerca di Milano, Via Celoria 2, 20133 Milano (Italy).

Abstract

Young leaves of two rose cultivars, one susceptible (rose Cardinal) and the other moderately resistant (rose Q. Elizabeth) to mildew infection, were either inoculated with Sphaerotheca pannosa or wounded with glass or metal needles. At different times after these treatments the presence of callose, lignin and phenolics in the infected or wounded cells was revealed by histochemical reactions. After either treatment no difference was found between the cultivars in the amount or earliness of deposition of callose or lignin, while phenolics were present in far larger amounts in the resistant cultivar. It is therefore suggested that one of the factors of rose resistance to powdery mildew might be the capacity to synthesize large amounts of phenolic compounds, also in view of the fact that the vacuoles of healthy epidermal cells are strongly electron opaque in rose Q. Elizabeth, while they are much more transparent in rose Cardinal.

Zusammenfassung

Wirt-Parasit-Beziehungen in einer anfälligen und einer resistenten Rosensorte nach Infektion mit Sphaerotheca pannosa

Junge Blätter einer anfälligen (Rose Cardinal) und einer mäßig resistenten Sorte (Q. Elisabeth) wurden mit Sphaerotheca pannosa infiziert oder mit Glas- oder Metallnadein verletzt. Nach verschiedenen dieser Behandlungen wurden Kallose, Lignine und Phenole nachgewiesen. Kein Unterschied wurde bei Kallose und Lignin gefunden; phenolische Verbindungen waren in der resistenten Sorte weit höher vorhanden.

Ancillary