Fig. 1 Identification of laticifer cells in petiole-derived calli of rubber tree by histochemical staining A: The transverse section of secondary laticifer cells in the trunk bark of rubber tree; B: The transverse section of primary laticifer cells in the branch bark of rubber tree; C: The 80-day old callus derived from the petiole of rubber tree; D: The transverse section of laticifer cells in petiole-derived calli. Blue arrows indicate laticifer cells; red arrows indicate tannin-containing cells; green arrows indicate starch-containing cells. Bars: A, B, D, 40 μm; C, 0.5 cm.

Fig. 2 Identification of laticifer cells in petiole-derived calli of rubber tree by nile red fluorescence staining A: Rubber particles of latex showing yellow under fluorescence; B: Laticifer cells in petiole-derived calli containing less rubber particles in early developmental stage; C: Laticifer cells in petiole-derived calli were full of rubber particles in late developmental stage. A1, B1 and C1 are the photos under visible light; A2, B2 and C2 are the corresponding photos under fluorescence. Arrows indicate laticifer cells. Bars: 20 μm.

Fig. 3 Identification of laticifer cells in petiole-derived calli of rubber tree by immunohistochemistry A: The treatment of the rabbit anti-SRPP antibody; B: The treatment of the rabbit anti-REF antibody. Arrows indicate laticifer cells. Bars: 20 μm.

Fig. 4 Amplification of latex specific gene fragments from petiole-derived calli by RT-PCR M means marker. The lanes of 1-4 are REF, SRPP, Hevein and CPT, respectively.