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Infrared absorption spectra of film specimens of oat coleoptile cell walls, before and after protease treatment and after treatment for removal of lipid materials, pectic substances and hemicellulose, were recorded, and the characteristic bands in the spectrum of the wall assigned. Polarization spectrum measurements on the wall provided evidence indicating that the non-cellulosic polysaccharide matrix as well as cellulose micronbrils has an oriented structure in the wall and that the oriented structure changes during extension growth as well as upon mechanical extension of the walls.

Infrared evidence indicated that the oriented structure of matrix polysaccharides changed on mechanical extension as well as during extension growth of Nitella cell walls. The importance of the ultrastructure of polysaccharide gels in controlling extension growth is discussed.

Polarized infrared absorption spectra of film specimens of the epidermal cell wall of the third internode of pea stems were recorded before and after treatment with endopolygalacturonase (endo-PG) and endo-pectin lyase (endo-PL). The spectra showed that the pectic polysaccharides solubilized with endo-PG were essentially the same as those solubilized with endo-PL. The degree of esterification of the pectic polysaccharides was about 20%, and their major sugar components were uronic acids (32.8%), arabinose (48.1%) and galactose (19.2%). The polarized infrared spectra showed that pectic polysaccharides have an oriented structure in cell walls with their molecular chains oriented preferentially parallel to the direction of cell elongation.

By a direct microinjection through pressurized glass micropipettes, we injected fluorescent Lucifer Yellow, berberine and berberine-bound DNA into protoplasts isolated from cultured Euphorbia millii cells and from tobacco mesophyll cells. The protoplasts to be injected were held by a holding pipette with which the cytoplasm or nucleus of the protoplasts could be oriented with reference to the tip of the injection pipette. Upon microinjection of a berberine-bound DNA, the nucleus and intranuclear organelles, possibly including nucleolus, specifically exhibited yellow fluorescence due to berberine. This provides a direct evidence that DNA molecules can be microinjected into the intranuclear compartment of the protoplasts. The injected protoplasts survived the capillary microinjection.

Protoplasts isolated from cultured cells of Coptis japonica and Euphorbia millii were electrically fused using platinum microelectrodes. The process involved two stages, cellular and vacuolar fusion, which are characterized respectively by transient wrinkling of the membrane and the formation of a dark-red precipitate.

The effects of three physical parameters upon protoplast electrofusion were studied using protoplasts from cultured cells of Coptis japonica and Euphorbia millii. The osmotic potential of the medium did not appreciably affect the AC-field-induced protoplast-pair formation, but significantly influenced the fusion process of the paired protoplasts in response to DC pulses. The optimum osmotic potential was 0.55 to 0.60 Osm/kg H2O in our system. The density of the medium markedly influenced both pair formation and fusion process. The optimum density was 1.13 to 1.14 g/cm3, and at this density the yield of the fused protoplasts increased to more than twice that of the control (1.10 g/cm3). Hydrophilic coating of the bottom surface of the chamber with Gellan gum or polyacrylamide gel was also effective for both pair formation and the fusion process, while coating with hydrophobic silicone was entirely inhibitory. Possible interpretations of the effects of these physical parameters upon protoplast electrofusion are presented.

Replacement of calcium ion with magnesium ion in the cell wall of the pea epicotyl makes the wall more extensible. A possible role of this differential effect of Ca2+ and Mg2− in regulating cell elongation in pea epicotyl is discussed. The ratio of the content of calcium ion to that of magnesium ion (Ca2+/Mg2+) in the walls decreased markedly in the order of the first > the second > the third internodes of the pea epicotyl. The capacity of the walls for cation exchange increased in the same order, whereas the calcium-magnesium ion exchange selectivity of the walls was virtually constant. Our results indicate that the changes in the Ca2+/Mg2+ ratio among the internodes is not attributable to the ion exchange properties of the walk per se, but is due to other physiological conditions which regulate the activities of free calcium and magnesium ions in the environment with which the walls are in equilibrium.

The increase in the dichroism of the ester-C=O and COO− bands in response to mechanical extension in oat coleoptile cell walls was much enhanced by IAA pretreatment while the decrease in that of the C-O-C band was not enhanced or even suppressed. The results indicate the importance of the ultrastructure of non-cellulosic polysaccharides in controlling auxin-induced cell elongation.

Infrared absorption spectra of film specimens of the epidermal and parenchyma cell walls of the third internode of pea stem, before and after protease treatment and after treatment for removal of lipid materials, pectic substances and hemicellulose, were recorded, and characteristic bands in the spectrum of the wall were assigned. Polarization spectrum measurements of the wall provided evidence indicating that the non-cellulosic polysaccharide matrix as well as cellulose microfibrils has an oriented structure in the wall which changes during extension growth as well as upon mechanical extension of the walls.

Protoplasts isolated from suspension-cultured cells of high-berberine-producing Coptis japonica (Polycarpiidae) and of high anthocyanin-producing Euphorbia millii (Sapindaifloriidae) were electrically fused. The “inter-infraclass” heterokaryons were manually selected with a glass micropipette, using the dark red vesicles which had formed in them as markers, and cultured in a microculture chamber in the presence of nurse cells. Various culture conditions were examined. Among a total of 2,830 heterokaryons, three showed cell division and one developed into a small cell colony of 10 to 20 cells after 260 days of culture.

Permeability coefficients for the cell membrane of Nitella jlexilis have been determined for some organic substances by measuring their transcellular transport with the double chamber method. Benzyl alcohol is rapidly taken up in the vacuole of the cell. In the double chamber method benzyl alcohol taken up in the vacuole at one end of the cell is not as rapidly transported to the other end as expected from the rate of protoplasmic streaming in the vacuole. This can be explained by assuming the presence of a “non-streaming part” in the vacuole. The uptake of urea into the streaming part of the cell is stimulated by directly illuminating the part where the cell is immersed in urea solution.