Aerial Plant Surface Microbiology

Abstract

The leaf surface constitutes the interface between the external environment and the plant tissues. It is limited by a thin layer (about 1.0 µm), the cuticle, composed of non soluble lipid polymers (the cutin) in which soluble lipid waxes are embedded. The function of the cuticle is to protect the leaf from external (biotic and abiotic) aggressions and to regulate the passage of water from the plant to its environment (Schönherr, 1976), of inorganic ions (Ferrandon and Chamel, 1989), and organic solutes (Tukey, 1970; Mengel et al., 1990) coming from tissues and particularly from the extracellular matrix and intercellular air spaces (apoplast). Under natural conditions many factors may cause injury to leaf surfaces: indirectly such as physiological disorders, nutrient and moisture deficiencies, adverse temperatures, poor aeration, deficient light and leaching and directly such as invasion of micro-organisms, attack by insects, wind and air pollution, (Tukey, 1963).