Symplastic transfer of fluorescent dyes from mesophyll to sieve tube in stripped leaf tissue and partly isolated minor veins of Commelina benghalensis

• Published in: Plant physiology (Bethesda) Vol. 88; no. 3; pp. 667 - 670
• Main Authors: Kesteren, W.J.P. van, Schoot, C. van der, Bel, A.J.E. van
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.11.1988
• Subjects: Biological and medical sciences; COLORANT; COLORANTES; DYES; Electrodes; FEUILLE; FLOEMA; Fluorescence; Fundamental and applied biological sciences. Psychology; HOJAS; LEAVES; Membranes and Bioenergetics; MESOFILO; MESOPHYLL; Mesophyll cells; MESOPHYLLE; Metabolism; Metabolism. Physicochemical requirements; MONOCOTILEDONEAS; MONOCOTYLEDONE; MONOCOTYLEDONS; PHLOEM; Phloem loading; PHLOEME; Plant cells; Plant physiology and development; Plant tissues; PLANT VASCULAR SYSTEM; Plant veins; Sieve tubes; SISTEMA VASCULAR DE LA PLANTA; SYSTEME VASCULAIRE DES PLANTES; Translocation; Commelinaceae; Monocotyledones; Phloem; Sap; Angiospermae; Spermatophyta; Anatomy; Conductive tissue
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.88.3.667

We have stripped small (3 × 3 mm) fields of the upper and the opposite lower epidermis of Commelina benghalensis leaves. Pectinase treatment of the resulting chlorenchyma windows produced free-lying viable minor veins with small lumps of mesophyll cells attached. These veins were still connected with the intact remainder of the leaf. Fluorescent dyes were injected into mesophyll cells or mestome sheath cells. Continuous following of the dye from the moment of injection and use of the simple vein system allowed an unhindered and precise assessment of the cell-to-cell route of dye transfer. Disodium fluorescein and Lucifer Yellow CH injected into mesophyll or mestome sheath cells readily moved to the sieve tube. This symplastic dye transfer from mesophyll to sieve tube was also observed after injection into unmacerated stripped leaf tissue. The displacement of fluorescent dyes substantiates a symplastic continuity between mesophyll and sieve tube and therefore supports the possibility of symplastic phloem loading.