Cell Cycle analysis with flow cytometry
Hypocotyls of more than 3 seedlings were collected for cell cycle analysis. Samples were chopped in ‘Aru’ buffer and filtered by the metal mesh with 30μm pore size (Arumuganathan & Earle, 1991; Bao, Zhang, & Hua, 2014). More than 5,000 nuclei in each sample were stained with propidium iodide and measured in BD flow cytometer. Three biological replicates were analyzed for each tomato variety. Endocycle index or the cycle value were calculated to quantify the extent of endocycle using the following formula (Bainard, Bainard, Henry, Fazekas, & Newmaster, 2012; Barow & Meister, 2003): EI = (%4C nuclei x 1) + (%8C nuclei x 2) + (%16C nuclei x 3) + (%32C nuclei x 4).