Fig. 7: Uptake and transport of FITC-Isoleucine (Ile) and FITC-Leucine (Leu) from pumpkin (Cmo) rootstock to cucumber (Csa) scion under chilling stress.

a Bright-field and fluorescence images of grafted plants, roots, stems, and petioles of Csa/Csa and Csa/Cmo plants after root irrigation with 50 μM FITC-Ile and FITC-Leu under normal (28 °C) and cold stress (4 °C for 12 h) conditions. H₂O was used as the control. BF bright-field images, FITC fluorescence images of FITC-Ile and FITC-Leu (channel RGB = 0:18:0) manually extracted using ImageJ, UV fluorescence detected using a LUYOR-3415RG fluorescent protein lamp. Fluorescence images of roots and vascular bundle sheath (VBS) cells in stem cross-sections and petioles were captured using a confocal laser scanning microscope (TCSSP8, Leica) with an excitation wavelength of 488 nm. Three individual plants were analyzed per treatment. b, c Statistical analysis of FITC fluorescence intensity per pixel, quantified using ImageJ software. Each treatment includes n = 3 biological replicates, with 5 individual plants per replicate (mean ± s.d.). Statistical significance was determined by one-way ANOVA followed by Duncan’s multiple comparisons test with the wild type as the control (p < 0.05). Source data are provided as a Source Data file.