Subsidiary cells

Subsidiary cells Surround guard cells of stomata Reservoirs for water and ions... 

The H2O lost from a leaf during transpiration evaporates from the cell walls of mesophyll cells (Figs. 1-2 and 8-4), the inner sides of guard cells, and the adj acent subsidiary cells. If the cell walls were uniform and wet, then most of the water would evaporate from the immediate vicinity of the stomatal pores. However, the waxy material that occurs on the cell walls within a leaf, especially on guard cells and other nearby cells, causes much of the water to evaporate from the mesophyll cells in the leaf interior. We can imagine that the water vapor moves in the intercellular air spaces (area Aias) toward the leaf surface by diffusing down planar fronts of successively lower concentration. Our imaginary planar fronts are parallel to the leaf surface, so the direction for the fluxes is perpendicular to the leaf surface. When we reach the inner side of a stomatal pore, the area for diffusion is reduced from... 

Second Type.—After the cutting off of the stomal mother-cell there are cut off on either side portions of neighboring epidermal cells which form subsidiary cells to the stoma. This condition is seen in Graminece, Cyperacece, Juncacece, in various species of Aloe, Musa and ProteacecB. 

Third Type.—Instead of two parallel subsidiary cells, four are cut off, as in Heliconia, in species of Tradestantia, Araucaria, or four co five, as in Ficus elastica, or four to five or more, as in the Conifircs and Cycads. J... 

Fourth Type.—Instead of only four subsidiary cells, each of these again subdivides by parallel walls, more rarely by radial walk, into eight radiating subsidiary cells, as in Maranta hicolor, Pathos argyrma, some of ProteacecB, etc. 

Fifth Type.—The stomal mother-cell divides once or several times before becoming the true mother-cell of the stoma. As a result of the divisions there are also formed one or more subsidiary cells. This mode of development is seen in the Lahiatas, Papilio-nacem, Cruciferce, SolanacecB, Crassulacece, Cactacew, and Begornacea, also in a number of ferns. 

Fig. 3-6. Scanning electron micrographs of adaxial leaf surfaces of Helianthus annuus, Phaseolus vulgaris, and hybrid clones of Populus exposed to simulated acid rain pH 2.7 or pH 3.0 from one to several rainfalls. 3. Several flaccid subsidiary cells surround the guard cells of the stoma of Helianthus annuus. 4. Epidermal cells that surround...

Fig. 7-10. Leaf cross sections of Phaseolus vulgaris > hybrids of Populus sp., and Quercus palustris after one to several rainfalls of simulated acid rain of low pH. Fig. 7. Initial injury of epidermal cells near a trichome hydathode. Note injury is greatest at the anticlinal walls of epidermal cells at the base of a hydathode on P. vulgaris. Fig. 8. Initial injury of subsidiary cells near the guard cells of a stoma. The cells of the palisade parenchyma appear normal on P. vulgaris. Fig. 9. A large lesion with an injured adaxial epidermis, palisade parenchyma, and spongy parenchyma near vascular tissues in poplar. Fig. 10. A cross-section of a gall on a leaf of palustris. Note both collapsed epidermal and palisade cells. Hypertrophy and hyperplasia of spongy mesophyll cells are also evident.

Fig. 5.29. Transmission electron micrograph of a stoma on stem of Opuntia ficus-indica. V, vacuoles m, mitochondria n, nucleus p, plastids po, stomatal pore (slightly open) sn, nucleus of a subsidiary cell (from Thomson and De Journett, 1970 a, by permission)...

The epidermis of leaves fixed 24 hours and 48 hours after treatment showed a variety of abnormalities of stomatal development. Most conspicuous was the complete suppression of the formation of subsidiary cells. In addition, many of the GCMC s did not divide at all, and a considerable proportion of them divided with their mitotic spindles parallel to the long axis of the leaf, so that the two guard cells were placed in proximal-distal rather than lateral positions relative to each other (Fig. 9). Guard cell complexes of this type will hereafter be termed proximal-distals. 

Fig. 9. Photographs of stomatal complexes on the leaf epidermis of barley, showing normal and proximal-distal orientations of guard cells. (A) Normal orientation. (B, C) Proximal-distal orientations obtained after treatment with 5-fluorodeoxyuridine, (B) with one subsidiary and (C) with no subsidiary cell. (D) Complex from the series treated with actinomycin D, showing the unusual condition produced by two successive proximal-distal divisions of the GCMC, flanked by two subsidiaries.

Fig. 10. Stomatal complex of a normal leaf at the time of subsidiary cell formation, showing the convex shape of the proximal and distal walls.

A subsidiary of lEC and Toshiba Corp. called ONSI Corp. was formed for the commercial development, production, and marketing of packaged PAEC power plants of up to 1-MW capacities. ONSI is commercially manufacturing 200-kW PAEC systems for use in a PC25 power plant. The power plants are manufactured in a highly automated faciHty, using robotic techniques to assemble the repeating electrode, bipolar separator, etc, units into the fuel cell stack. 

Dead Sea Works Process. The Dead Sea Works, a subsidiary of Israel Chemicals Ltd., aimounced plans ia 1992 to constmct a 25,000 t/yr magnesium plant at Beer-Sheva, Israel. The plant, to be based on Russian camaHite technology, is designed to use an existing potash plant as the source of camaHte. The chlorine by-product can be either Hquefted and sold, or used ia an existing bromine plant. Waste streams from the camaHite process, as well as spent electrolyte from the electrolytic cells, can be returned to the potash plant. 

A.sahi Chemical EHD Processes. In the late 1960s, Asahi Chemical Industries in Japan developed an alternative electrolyte system for the electroreductive coupling of acrylonitrile. The catholyte in the Asahi divided cell process consisted of an emulsion of acrylonitrile and electrolysis products in a 10% aqueous solution of tetraethyl ammonium sulfate. The concentration of acrylonitrile in the aqueous phase for the original Monsanto process was 15—20 wt %, but the Asahi process uses only about 2 wt %. Asahi claims simpler separation and purification of the adiponitrile from the catholyte. A cation-exchange membrane is employed with dilute sulfuric acid in the anode compartment. The cathode is lead containing 6% antimony, and the anode is the same alloy but also contains 0.7% silver (45). The current efficiency is of 88—89%, with an adiponitrile selectivity of 91%. This process, started by Asahi in 1971, at Nobeoka City, Japan, is also operated by the RhcJ)ne Poulenc subsidiary, Rhodia, in Bra2il under Hcense from Asahi. 

Provided that the solution in a reversible half-cell contains the requisite solutes, it may also contain one or more other solutes which do not react with the electrode at all the electrode will still function properly. The Ag/AgCl half-cells mentioned in See. 118 will contain one or two such subsidiary solutes. These solutes, which will also be present in the other half-cell to which the Ag/AgCl half-cell is coupled, react with the electrode there they are included in the Ag/AgCl half-cell at the same concentration in order to avoid the electrical double layer which would otherwise be set up at the junction between the two solutions— at the liquid junction between the two half-cells. 

Fig. 7. Variation in cell death rates with average energy dissipation rate for capillary and jet flows. From reference [59], redrawn with permission. 1998, Wiley-Liss, Inc, a subsidiary of John Wiley Sons, Inc...

Provesteen A microbiological process for making single-cell protein from methanol, ethanol, or whey, developed in the 1980s by Provesta Corporation, a subsidiary of Phillips Petroleum Company. The basis of the process is a special high cell-density fermenter, which simplifies the isolation of the product from the water. The organism is the torula yeast the intended products are speciality flavor enhancers, a high fiber food bar, a food supplement... 

Elite (Brisbane) 7000 Gaseous chlorine to hypo and HCI manufacture Subsidiary of Ionics Inc. Ionics membrane cells... 

GM s international Global Alternative Propulsion Center is responsible for developing fuel cells for world markets. The center has several operations in Germany, where in concert with German subsidiary Opel, it has built the Zafira fuel cell minivan. 

IdaTech LLC (formerly Northwest Power Systems), of Bend, Oregon, an Idacorp subsidiary, delivered the first of 110 planned fuel cell systems to the Bonneville Power Administration (BPA), Portland, Oregon in June 2000. The BPA program is part of a fuel cell test and development phase intended to commercialize fuel cell systems for home and small commercial applications by 2003. 

Bewag AG s Treptow heating plant, located in Berlin, Germany received a 250 kW PEM fuel cell unit in April 2000 from Ballard Generation Systems, a subsidiary of Ballard Power System, of Burnaby, BC, Canada. 

In order to determine the net current flowing, i, as a function of q (and in some cases time) it is generally necessary to work with three or four electrode cells where the electrode of interest (the working electrode) carries current into the cell and a second electrode (the auxiliary or subsidiary electrode) carries the current out of the cell. The third electrode is the reference electrode although in cases where one of the phases is not a metal a second reference electrode is required (four electrode cell). 

Fig. 10.9 Schematic representation of a three electrode cell. W - working electrode R -reference electrode and S - subsidiary electrode. Note that the reference electrode is placed as close as possible to the working electrode.

Gas compression in closed-cell polymer foams was analysed, and the effect on the uniaxial compression stress-strain curve predicted. Results were compared with experimental data for a foams with a range of cell sizes, and the heat transfer conditions inferred from the best fit with the simulations. The lateral expansion of the foam must be considered in the simulation, so in subsidiary experiments Poisson s ratio was measured at high compressive strains. 13 refs. 

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