Photosynthesis, inhibitors

Investigating the effects of photosynthesis inhibitors, uncouplers, and redox systems, Nultsch90-94,96,97), Nultsch and Jeeji-Bai104), and Hader41) found that inhibi-... [Pg.120]

Plumley, EG. and D.E. Davis. 1980. The effect of a photosynthesis inhibitor atrazine, on salt marsh edaphic algae, in culture, microecosystems, and in the field. Estuaries 3 271-277. [Pg.801]

Plumley, EG., D.E. Davis, J.T. McEnerney, and J.W. Everest. 1980. Effects of a photosynthesis inhibitor, atrazine, on the salt-marsh fiddler crab, Uca pugnax (Smith). Estuaries 3 217-223. [Pg.801]

Ot and photo-oxidants Pulmonary oedema, emphysema, asthma, eye. nose, and throat irritation, reduced lung capacity. Vegetation damage, necrosis of leaves and pines, stunting of growth, photosynthesis inhibitor, probable cause of forest die-back, suspected cause of crop loss. Attack and destruction of natural rubber and polymers, textiles and materials. [Pg.155]

Photosynthesis inhibitor, via blockage of the plastoqui-none binding site... [Pg.34]

Figure 15.2 Illustration of the relative sensitivity of plants to a photosynthesis inhibitor acting on a receptor and insensitivity of fish, which lack the receptor.

The pyridazin-3-ones are interesting because they include herbicides having two different modes of action, distinguished only by small changes in substitution pattern. Thus pyrazon (8) (61GEP1105232) is a photosynthesis inhibitor, while other discussed later are carotenoid biosynthesis inhibitors. The pyridazin-3-one ring is constructed by condensation of phenyl-hydrazine with 3,4-dichloro-2,5-dihydro-5-hydroxyfuran-2-one (9), in turn produced by chlorination of furan-2-carbaldehyde. Amination of (10) then occurs exclusively at the 5-position to give pyrazon (Scheme 4). [Pg.188]

White and coworkers used trans Addition of bromine and (-)-l-bomeol to 3,4-dihydro-2//-pyran to afford the stereoisomeric bomyl bromotetrahydropyranyl ethers (3) and (4 Scheme 44) which are employed in an enantioselective total synthesis of (-)-monic acid C (Scheme 5).10 A simple synthesis of 4-methylthio-l,2-dithiolane, the photosynthesis inhibitor of the green alga Chara globularis (Scheme 45),83 exploits the observation that allylic sulfides undergo rearrangement on addition of bromine.84 Block and Naganathan employed the trans addition of bromine to 4-thioacetoxycyclopentene as a key... [Pg.345]

The phenolic derivatives indicated in Figure 8.1 are also bound to the same binding niche on PS II as the triazines (Oettmeier, 1992). However, they have a somewhat different inhibition pattern than the classical family of PS II herbicides (e.g., triazines and ureas) and, therefore, were regarded as a separate family with a somewhat different mode of action (Van Rensen et al., 1978 Trebst and Draber, 1986). It is now clear that they just orient somewhat differently in the same binding niche, as discussed below. Although the phenolics are photosynthesis inhibitors, dinoseb and the halogenated benzonitriles also inhibit respiration. [Pg.104]

Draber, W. (1992). Structure-activity studies of photosynthesis inhibitors. In W. Draber and T. Fujita, eds., Rational Approaches to Structure, Activity and Ecotoxicology of Agrochemicals. Boca Raton CRC Press, pp. 277-313. [Pg.108]

When adopting the functional redundancy principle, the emphasis is on ecosystem processes impacts are considered acceptable when functional attributes are not changed, despite possible effects on community structure. Functional endpoints are rarely more sensitive than structural ones (Ellis 1989 Kersting 1994 Klepper et al. 1999) however, an exception is found in the photosynthesis inhibitors such as the triazines and urea classes of herbicides. Effects on functional endpoints indicate the limit of functional redundancy within the stressed community. Once ecosystem processes have changed due to contamination, this is usually an indication of severe effects on structural endpoints. [Pg.14]

Leaf discs have commonly been used for bioassays to determine if herbicides inhibit photosynthesis (Table 16.2). The simplest leaf-disc bioassay uses small discs cut from fully expanded cucumber or pumpkin cotyledons, floated in the light on a phosphate buffered medium containing suspected photosynthesis inhibitors.115 Qualitatively, if photosynthesis is inhibited, the leaf disc sinks. There are several variations of this method that can provide quantitative data. Evolution of O2 in the test solution can be measured with an oxygen electrode, CO2 induced pH changes colorimetrically determined with bromothymol-blue, or electrolyte leakage monitored with a conductivity meter. Leaf strips, algae, isolated chloroplasts, and duckweed (Lemna minor) have been used as test subjects. Although the bioassays presented in Table 16.2 are fairly easy to perform, few allelochemicals have been tested as possible inhibitors of photosynthesis. Many... [Pg.340]

Saltzman, S. and Heuer, B. 1985. A rapid bioassay for the detection of photosynthesis inhibitors in water. Weed Sci. 24, 250-252... [Pg.361]

Starvation. The early reports that Hill inhibitors limited photosynthesis and that starch disappeared from treated plants, prompted some investigators to refer to these compounds as photosynthesis inhibitors. Photosynthesis is inhibited because ATP and NADFH are not available for carbon dioxide fixation. However, there is little evidence that the plants starve to death. If this were the only process affected, phytotoxic symptoms should resemble those that appear on plants kept in total darkness. Deficiency of photosynthate does limit new growth, but does not account for the morphological alterations that occur within a few hours after treatment. The mechanisms that lead to phytotoxicity appear to be considerably more complex than would result from limiting carbohydrate synthesis by suppression of carbon dioxide fixation (2). ... [Pg.75]

To investigate the influence of a photosynthesis inhibitor on the growth of the hairy roots, 0-10 mmol m 3 of 3-(3,4-dichlorophenyl)-l, 1-dimethylurea, DCMU, was supplemented in the medium according to the procedure described by Horn et al. [21]. The dishes were incubated in a chamber under the varied C02 concentrations of 0.03-8.5%. [Pg.190]

These suggest that the proliferation of the derived cell line of photoautotrophic pak-bung hairy roots is dependent entirely on photosynthesis for acquiring carbon and energy sources because DCMU blocks the reaction in photosynthetic process as shown in Fig. 6. In addition,based on the sensitive response to DCMU, a kind of photosynthesis inhibitor, the photoautotrophic hairy roots maybe used to detect some herbicides existing in the surroundings. [Pg.198]

An aspect not covered by the models discussed so far is the extra level of integration for species assemblage-level problems, that is, ecological interactions. When quantitative risks can be established for separate subgroups, it might become possible to address this issue further. When a mixture of photosynthesis inhibitors would affect 100% of the plant species, simple reasoning suggests that other species will go extinct... [Pg.180]

Sidoova E, Kralovam K, Loos D (1998) Synthesis of 2-(6-acetamidobenzothiazolethio)acetic acid esters as photosynthesis inhibitors. Molecules 3 135-140... [Pg.92]

Its mode of action is similar to other photosynthesis inhibitors in that its activity is dependent on light. It inhibits photosynthetic carbon dioxide fixation and photosynthetic electron transport. [Pg.177]

Sears, P. G., Wolford, R. K., and Dawson, L. R. (1956). Conductances of some acids, bromides, and picrates in dimethylformamide at 25°C. J. Electrochem. Soc. 103, 633-636. Senesi, N. (1981). Free radicals in electron donor-acceptor reactions between a soil humic acid and photosynthesis inhibitor herbicides. Z. Pflanzenernahr Dung. Bodenkd. 144, 580-586. Senesi, N., Chen, Y., and Schnitzer, M. (1977a). Hyperfine splitting in electron spin resonance spectra of fulvic acid. Soil Biol. Biochem. 9, 371-372. [Pg.628]

It has been shown that the enantioselectivity of the reduction of ketones by the photosynthetic cyanobacterium Synechococcus elongatus PCC 7942 is regulated by light. In the case of the ketone (28), the enantioselectivity is reduced by over 50% in the absence of light (Nakamura and Yamanaka, Chapter 5). It was also shown that a known photosynthesis inhibitor decreases both the chemical and enantiomeric purities of the products, which suggests that physiological changes on irradiation alfect the enzymatic activity of cyanobacteria. [Pg.289]

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