Resumen: Changes in starch in small structures are associated with key events during several plant developmental processes, including the reproductive phase from pollination to fertilization and the onset of fruiting. However, variations in starch during flower differentiation are not completely known, mainly due to the difficulty of quantifying the starch content in the particularly small structures of the flower primordia. Here, we describe a method for the quantification of starch in the ovary primordia of sweet cherry (Prunus avium L.) by using an image analysis system attached to the microscope, which allows relating the changes in starch content with the different phases of dormancy from autumn to spring. For this purpose, the dormancy status of flower buds is determined by evaluating the bud growth of shoots transferred to controlled conditions at different moments in winter time. For the quantification of starch in the ovary primordia, flower buds are sequentially collected, fixed, embedded in paraffin wax, sectioned, and stained with I2Kl (potassium iodide-iodine). Preparations are observed under the microscope and analyzed by an image analyzer that clearly distinguishes starch from the background. Starch content values are obtained by measuring the optical density of the image that corresponds to the stained starch, considering the sum of the optical density of each pixel as an estimation of the starch content of the frame studied. Idioma: Inglés DOI: 10.3791/58524 Año: 2019 Publicado en: Journal of visualized experiments : JoVE 145 (2019), e58524 [9 pp] ISSN: 1940-087X Factor impacto JCR: 1.163 (2019) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 45 / 71 = 0.634 (2019) - Q3 - T2 Factor impacto SCIMAGO: 0.57 - Biochemistry, Genetics and Molecular Biology (miscellaneous) (Q2) - Chemical Engineering (miscellaneous) (Q2) - Immunology and Microbiology (miscellaneous) (Q3) - Neuroscience (miscellaneous) (Q3)