Fig. 1.

Effects of carbohydrate stress treatment (girdling plus defoliation, GPD) on the cumulative fruitlet abscission rate, phenotypic performance, and cell separation in the fruitlet abscission zone (FAZ) of litchi. (A) Cumulative fruitlet abscission rate. Data are means (±SE) from three replicates. Significant differences between GPD and control branches were determined using Student’s t-test: *P<0.05. (B) Phenotypic characteristics of FAZs during the fruitlet abscission process. The images on the right show magnifications of the FAZs at 3 d after GPD treatment. Arrows indicate the location of the abscission layers. (C, D) Longitudinal sections of the FAZs from fruitlets from control (C) and GPD-treated (D) branches stained with Safranin O and Fast Green at 4× and 20× magnification, respectively. Arrows indicate the location of the abscission layers. CT, cortex; EC, expanding cells; PI, pith; VB, vascular bundle. Scale bars are 200 μm at 4× magnification and 50 μm at 20× magnification. (E) Longitudinal sections of FAZs from control and GPD-treated branches at 1 d and 3 d after treatment. Scale bars are 50 μm. (F) Cell number, cell length, and cell width of the FAZs. A vision field of ~10 000 μm² (shown by the dashed lines in E) were used to count cell numbers. Up to 90 cells were used to measure the length and width. Significant differences between GPD and control branches were determined using Student’s t-test: **P<0.01, for at least three longitudinal sections.