Determination of Cell Division and Expansion Periods in Melon Seedling

This study aimed to investigate the cell division and expansion processes occurring in cortical cells after germination in melon (Cucumis melo L.) seedlings over time. Cell size and cell number were measured in hypocotyl cross-sections taken at certain intervals from the 4th day to the 18th day after germination, and the obtained data were evaluated statistically. The results show that cell division is particularly intense in the early period (between the 4th and 10th days), and after this period, cell number stabilizes and there is a significant increase in cell size. These findings reveal that cortical tissue development in melon hypocotyl follows a two-phase model: the first is the cell division phase, in which mitotic activity is dominant, and the second is the growth phase, in which cell expansion is prominent. In addition, it was concluded that the application of mitosis-promoting hormones such as cytokinin during the division period and growth-promoting regulators such as gibberellic acid during the expansion period can optimize tissue development. This study contributes to the development of timing-based growth management strategies for seedling and tissue culture applications.