Localization of polysaccharides in isolated and intact cuticles of eucalypt, poplar and pear leaves by enzyme-gold labelling.
The presence and characteristics of cuticle polysaccharides have been demonstrated by staining and spectroscopic methods, but their location in the cuticle remains unclear. Furthermore, according to the prevailing model, polysaccharides are believed to be restricted to the cuticular layer and absent in the cuticle proper. With the aim of gaining insight into cuticular ultra-structure focussing on polysaccharides, cellulose and pectins have been identified and located in the transversal sections of isolated and intact adaxial leaf cuticles of Eucalyptus globulus, Populus × canescens and Pyrus communis by means of enzyme gold-labelling (Au-cellulase, EC 3.2.1.4, and -pectinase, EC 3.2.1.15) and transmission electron microscopy (TEM). The structure of the interface between the cuticle and the cell wall underneath was observed to influence the process of enzymatic isolation of leaf cuticles. Cellulose and pectins were detected for the first time in enzymatically isolated cuticles, sometimes appearing closely underneath the epicuticular wax layer. The location and presence of polysaccharides in intact and isolated leaf cuticles may have multiple implications, such as when estimating the bi-directional transport of substances between plant organs and the surrounding environment, or when interpreting organ ontogeny. The results are discussed within a plant ontological and ecophysiological context.
Forest Genetics and Eco-physiology Research Group, School of Forest Engineering, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
Paula
P
Guzmán
Forest Genetics and Eco-physiology Research Group, School of Forest Engineering, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain. Electronic address: v.fernandez@upm.es.
Victoria
V
Fernández
Electron Microscopy National Centre, Faculty of Chemistry, University Complutense of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
María Luisa
ML
García
Department of Applied Physics I, Faculty of Physics, University Complutense of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
Mohamed
M
Khayet
Electron Microscopy National Centre, Faculty of Chemistry, University Complutense of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
Agustín
A
Fernández
Forest Genetics and Eco-physiology Research Group, School of Forest Engineering, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
Luis
L
Gil
D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry; D004798:Enzymes / Q000737:chemistry*; D005052:Eucalyptus; D006046:Gold / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010368:Pectins / Q000737:chemistry; D019441:Plant Epidermis / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry; D032107:Populus; D031989:Pyrus
D004798:Enzymes; D011134:Polysaccharides; D006046:Gold; D010368:Pectins; D002482:Cellulose
Cellulose; Cuticle; Gold-labelling; Leaf; Pectins; Polysaccharides; Transmission electron microscopy