High amounts of nuclear DNA in tomato (Lycopersicon esculentum Mill) pericarp

During tomato fruit development the DNA synthesis of the pericarp was measured, After staining of the isolated nuclei with DAPI the relative DNA amount was analyzed using a flow cytometer. Results showed that in the young green fruit the C-values are comparable with those of developing leaves i.e. predominantly cells with 2C and 4C DNA content, where C is the unit of DNA content of the genome of germ-line cells [1]. During further tomato fruit development most of the cells switch to higher C-values (up to 256C) and the tissue becomes highly polysomatic. These results are correlated to the data obtained by measuring the diameter of the nuclei of the pericarp tissue with a confocal scanning laser microscope, The diameter of the nuclei increased during fruit development similar to 6 times reaching a maximum in the red ripe fruit.