A cortical band of gelatinous fibers causes the coiling of redvine tendrils: a model based upon cytochemical and immunocytochemical studies.

A cortical band of fiber cells originate de novo in tendrils of redvine [Brunnichia ovata (Walt.) Shiners] when these convert from straight, supple young filaments to stiffened coiled structures in response to touch stimulation. We have analyzed the cell walls of these fibers by in situ localization techniques to determine their composition and possible role(s) in the coiling process. The fiber cell wall consists of a primary cell wall and two lignified secondary wall layers (S(1) and S(2)) and a less lignified gelatinous (G) layer proximal to the plasmalemma. Compositionally, the fibers are sharply distinct from surrounding parenchyma as determined by antibody and affinity probes. The fiber cell walls are highly enriched in cellulose, callose and xylan but contain no homogalacturonan, either esterified or de-esterified. Rhamnogalacturonan-I (RG-I) epitopes are not detected in the S layers, although they are in both the gelatinous layer and primary wall, indicating a further restriction of RG-I in the fiber cells. Lignin is concentrated in the secondary wall layers of the fiber and the compound middle lamellae/primary cell wall but is absent from the gelatinous layer. Our observations indicate that these fibers play a central role in tendril function, not only in stabilizing its final shape after coiling but also generating the tensile strength responsible for the coiling. This theory is further substantiated by the absence of gelatinous layers in the fibers of the rare tendrils that fail to coil. These data indicate that gelatinous-type fibers are responsible for the coiling of redvine tendrils and a number of other tendrils and vines.

[Hairy-root culture of Polygonium multiflorum Thunb. and the production of its active constituents-anthraquinones].

Transformed hairy roots of Polygonium multiflorum Thunb. were obtained by the transformation of Agrobacterium rhizogenes LBA9402. It was clearly demonstrated that T-DNA of A. Rhizogenes Ri plasmid was integrated into the cells of hairy roots by the experiments of PCR and Southern hybridization. Through the screen of basic medium and the research of growth curve of hairy roots, the optimum inoculum time was selected in 30 days or so in the optimum condition-MS medium. On the condition, the content of rhein was 2.85 folds higher in hairy roots than that of natural plants by means of HPLC.