Plants and Algae

The effects of salt stress have been investigated in perfused maize cells with and Na NMR. In cells exposed to salt stress there was a significant increase in vacuolar pH whilst the cytoplasmic pH remained constant. In concentrations of up to approximately 300 mM Na, vacuolar pH and the rate of Na uptake were dependent on the extracellular concentration above 300 mM, vacuolar pH and Na uptake were independent of the extracellular concentration. Na uptake into the cell was accompanied by a rapid increase in vacuolar Pi, broadening of the P resonances and a reduction in glucose monophosphate and UDPG.  

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FIGURE 22.15 The structures of plasto-quiuoue and its reduced form, plastohydro-quiuoue (or plastoquiuol). The oxidation of the hydroquiuoue releases 2 as well as 2 c. The form shown (plastoquinone A) has nine isoprene units and is the most abundant plastoquinone in plants and algae. Other plasto-quinones have different numbers of isoprene units and may vary in the substitutions on the quinone ring. 

Hortensteiner, S., Chlorophyll breakdown in higher plants and algae. Cell. Mol. Life... 

The photosynthetic apparatus in green plants and algae is located in the chloroplast, which is a flattened, double-membraned structure about 150-200 A thick/4,5 The two flat membranes lie one above the other and are united at their peripheries. These double-membraned structures have been termed thylakoids (from the Greek sacklike )/ Each membrane of the thylakoid consists of a water-insoluble lipoprotein complex which contains the light-absorbing chlorophyll and other pigments utilized in photosynthesis. 

The various chlorophyll types are listed in Table 12.1. An alternate resonance form is available for all the chlorophylls listed in Table 12.1 except for bacteriochlorophyll. Chlorophyll a is found in all green plants. In most land plants and algae one also finds chlorophyll b or d. Thus a more correct statement than the one made previously would be that chlorophyll a is the photochemically active pigment in all green plants, as shown by experimenta-tion.<8)... 

The process occurring in plants and algae by which water is oxidized to molecular oxygen and carbon dioxide is converted to carbohydrates in the presence of light is called photosynthesis. In addition to the products oxygen and carbohydrate, light energy is stored chemically in adenosine triphosphate (ATP) for later use for a variety of purposes. The production of... 

Rudd Scardinius erythrophthalmus), a medium-sized cyprinid species, is an herbivorous the bulk of its diet consists of plants and algae. However, small invertebrates, such as nematodes, larvae of a freshwater shrimp Atyaephyra des-maresti), larvae of small, littoral chironomids Paratanytarsus sp. and Cricotopus flavocinctus), and particularly microcrustaceans such as ostracods, are included. 

Schwender J, Zeidler J, Groner R, Muller C, Focke M, Braun S, Lichtenthaler FW, Lichtenthaler HK (1997) Incorporation of 1-deoxy-D-xylulose into isoprene and phytol by higher plants and algae. FEBS Lett 414 129-134... 

For animals, the ultimate sources of useable nitrogen and all other nutrients are plants and algae. Animals that consume these organisms ingest nitrogenous compounds as they feed. Those that eat other animals participate in food chains that lead eventually back to these organisms. As for plants, most of them assimilate ni-... 

Isotope effects during assimilation of Cr by plants and algae have not been studied. With higher plants we expect that, as with Se and S, the effects will be minimal because of the lack of communication between the plant interior, where reduction occurs, and the outside environment. With single-celled phytoplankton, there could be some fractionation, and this should be investigated as studies of Cr isotopes in the marine environment move forward. 

Figure 8. Specific activity of Radium in ordinary plants and algae (solid line) compared to Characeae algae (dotted line), showing roughly a linear relationship with the Radium activity concentration in the water.

The pH of the water on the surface of a submerged soil often depends on the activity of photosynthetic organisms. Photosynthesis by aquatic plants and algae removes dissolved CO2 during the day, but at night the net respiratory activity of the organisms returns CO2 to the water and the concentration of dissolved CO2 and acidity increase ... 

It is interesting that in photosynthesis the energy loss in the primary photochemical step is 0.8 eV for photosystems I and II of green plants and algae and also for photosynthetic bacteria (18). Also Xg = 700 nm for green plant and algal photosynthesis, a value near the optimum for the 0.8 eV C curve in Fig. 2. 

The list of plants, by-products and waste materials that can potentially be used as feedstock is almost endless. Major resources in biomass include agricultural crops and their waste by-products, lignocellulosic products such as wood and wood waste, waste from food processing and aquatic plants and algae and effluents produced in the human habitat. Moderately dried wastes such as wood residue, wood scrap and urban garbage can be directly burned as fuel. Energy from water-containing biomass... 

Bacteria indigenous to Cr(VI)-polluted areas are Cr(VI) tolerant and/or resistant and have been considered as potential candidates for bioremediation of Cr(VI)-contaminated sites.16 However, the ability of bacteria to reduce Cr(VI) to the less-toxic Cr(III) compounds may produce reactive intermediates (such as Cr(V), Cr(IV), radicals), which are known to be active genotoxins and are likely to be carcinogenic.17 Therefore, the formation and lifetimes of Cr(V) intermediates, produced via bacterial reduction of Cr(VI), need to be evaluated carefully if microorganisms are to be employed as a means for remediation of chromium-polluted subsurface environments. Similarly, Cr(V) accumulation should first be monitored when considering plants and algae as biosorption materials for the bioremediation in the event of chromium pollution.18... 

Submicrofibril and triple-stranded left-hand helical microfibrils are found in tobacco primary cell wall and bacterial A. xylinum cellulose. We suspect from our results and the literature survey outlined in reference (1) that the triple stranded structures are prominent in the primary plant cell wall. The highly crystalline cellulose of plant and algae secondary cell wall appears by X-ray fiber diffraction (18,19) and TEM lattice imaging (20-23) to be largely crystalline arrays of planar straight chains of (l-4)-/3-D-glucan chains. 

Plant type ferredoxins. Tagawa and Arnon (16) described the isolation of a ferredoxin from spinach chloroplast. This ferredoxin is a protein of 12,000 molecular weight, and consists of 97 amino acids (17). Spinach ferredoxin has abosrbance maxima at 325, 420 and 465 nm (18). Ferredoxins of this type have been isolated from other sources of plants and algae, e.g., alfalfa (19), taro (20), Leuceana glauca (21) and Scenedesmus (22). The prot s of thes erredoxins are similar in their properties to ferredoxin from spinach. 

The accumulation of nitrogen compounds in bodies of water, like Lake Superior in the Catskill Mountains of New York shown here, contributes to the growth of plants and algae, resulting in the rapid eutrophication of the lake. (Michael P. Gadomski/Photo Researchers, Inc.)... 

Photosynthesis and respiration help to maintain the concentrations of oxygen and carbon dioxide in the atmosphere. Respiration is the process by which carbohydrates (most commonly glucose) are broken down for the release of energy needed for life processes. Photosynthesis uses carbon dioxide and produces oxygen. Respiration does the opposite—it uses oxygen and produces carbon dioxide. Plants and algae carry on photosynthesis, while animals carry... 

As population and industrialization continue to expand, eutrophication has become a problem due to the accelerated aging of bodies of water by the excessive growth of plants and algae attributed to discharges of nitrates and phosphates. These pollutants have imposed demands on engineers to develop cost-effective systems that can eliminate them from water. 

Green plants and algae use the energy of sunlight to split water in the process of photosynthesis ... 

Figure F4.1.1 Structural differences between major classes of natural chlorophylls in higher plants and algae. Designation of pyrrole rings A-D and methene bridges a-5 is based on the nomenclature outlined by Fisher and Orth (1937).

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