Caratterizzazione micromorfologica di foglie in genotipi di Vitis

The leaf micromorphological features of 17 different genotypes of grapevine have been analyzed at Environmental Scanning Electron Microscope in order to achieve useful information for a better understanding of the relationship with the sensibility/tolerance to biotic and abiotic stress. The analysis showed leaves with stomata only on the abaxial side, scattered in the epidermis, with a great variability of position among accessions. Furthermore, raised and sunken stomata were visible in the same leaf with different ratios. In Vitis Berlandieri more than 99% of the stomata was protruding from the surface of the epidermis while the cv Nero d’Avola exhibited about 89% of sunken stomata. Mean stomatal density always ranged between 100 and 200 stomata/mm2, with significant differences amongst the accessions. The lowest values occurred in the wild grapevine and in Sangiovese but, concerning the size of stomata, these genotypes showed significantly larger and wider stomata when compared to the others. Density and types of trichomes differently characterize the leaves of studied Vitis accessions. Prostrate and erect hairs were mainly observed on abaxial side but in some genotypes they occurred also on upper epidermis. Key words: grapevine, electronic microscopy, stomata, hairs, abiotic stress