Photosynthetically active

For Pond 3513, the cycle of 2 3 8U and 239,2 °pu concentrations in water (filtered with a 0.22y membrane) is out of phase with the cycle of plutonium concentrations in Lake Michigan. In this shallow pond, the concentrations of the two actinides peak in summer and decline in winter. An explanation for this cycle of plutonium is that photosynthetic activity depletes dissolved CO2 which results in an increase in pH and this in turn shifts the oxidation state in favor of Pu(V) which is desorbed from the sediments(26). 

Numerous studies have shown that increased levels of UV affect photosynthetic activity (10-23), growth rate (24), nitrogen metabolism (25), and locomotion (26) of phytoplankton. Additionally, increases in UV-B are likely to alter community diversity as well as phytoplankton species composition. Thus, by weakening the base of the food web and altering trophodynamic relationships, UV-induced changes could potentially have far-reaching effects on the entire ecosystem. 

Kaiser, W.M. (1982). Correlation between changes in photosynthetic activity and changes in total protoplast volume in leaf tissue from hygro-, meso-, and xer-ophytes under osmotic stress. Planta, 154, 538-45. 

The oxygen evolution rate was measured by using the photosynthetic activity measurement system (Fig. 1). When light was illuminated to the reaction vessel, algal cells began to evolve oxygen and the linearity between dissolved oxygen and time was observed just after a few... 

The results of this study may be helpful to understand the light-dependent photosynthetic activity of H. pluvialis. At the same time, the information presented here can be used for enhancing the volumetric biomass productivity of the astaxanthin-accumulating alga. 

Another layering that occurs within the 1000 metre surface ocean is the distinction between seawater receiving solar irradiation (the photic zone) and the dark water below. The sun provides heat, UVR, and photosynthetically active... 

The desirability of partial shade on tea estates has been a controversial subject. Desirable effects include temperature moderation at the leaf surface, which decreases low-humidity stress, and an increased yield of chlorophyll, amino acid, and caffeine production. The undesirable effects include decreased photosynthetic activity and competition for water and solid nutrients by the shade tree employed. In general, the trend has been toward the elimination of shade in most black-tea growing areas. Green tea products benefit from the additional chlorophyll and amino acid pro-... 

C02 is not the only factor involved in photosynthesis, so that for its use, other factors must be at levels that do not limit the process. Light, temperature, amount of available nutrients and the relative humidity are other environmental factors affecting photosynthetic activity. 

As a result, organic fruit growers have to make maximum use of preventative or indirect plant protection measures, some of which were already described in terms of their effect on fruit quality (e.g. lower planting densities, see sections above). However, there remains an increased risk for pests and diseases causing stress, decreased photosynthetic activity and capacity. Also in certain sensitive cultivars, the application of permitted plant protection products (such as lime sulphur) can result in phytotoxic effects or latent stress in trees (Palmer et al, 2002). The decrease in photosynthetic activity by both pest/disease attack and pesticides may, in turn, result in reduced fruit quality. Both long-term latent and short-term acute side effects of organic plant protection products have not yet been sufficiently investigated. 

The photosynthetic activity of biofilms is one of the most commonly used approaches to detect effects on biofilms. The methods based on photosynthetic activity are obviously adequate in the case of stressors that affect the performance of photosynthesis, either directly or indirectly. 

Butcher, J.E., M.G. Boyer, and C.D. Fowle. 1977. Some changes in pond chemistry and photosynthetic activity following treatment with increasing concentrations of chlorpyrifos. Bull. Environ. Contam. Toxicol. 17 752-758. 

Giant kelp, Macrocystis pyrifera Duckweed 277 50% inhibition of photosynthetic activity in 4 days 70... 

Circadian rhythm of total protein synthesis— cytoplasm and chloroplasts of Gonyaulax polyhedra Sulfate incorporation in Udotea petiolata thalli Photosynthetic activity of phytoplankton Thymidine incorporation into Nostoc Chloroplast nucleoids of Zea mays Localization of chloroplast binding protein in cells of wheat leaves Distributon of [14C]-dichlorophenoxyacetic acid Donner et al. (13) Mariani and Favoli (14) Bourdier and Bohatier (15) Favoli and Grilli (16) Lindbeck et al. (17) Bronsema et al. (18)... 

Bourdier G, Bohatier J. Photosynthetic activity of phytoplankton visualized by autoradiography. Am Sci Mob Zoo Biol Anim 1986-1987 8 75-80. 

Uncoupling is a specific toxic effect that takes place in energy-transducing membranes (photosynthetically active membranes, inner mitochondrial... 

Besides these external processes, formation of ROS may also take place intrac-ellularly. Photooxidative stress, including UVB, stimulates various cellular processes leading to the production of superoxide radicals and hydrogen peroxide, as well as singlet-oxygen and hydroxyl radicals. The sources and production sites of ROS are mainly related to photosynthetic activities such as the pseudocyclic photophosphorylation and the Mehler reaction, which stimulate the accumulation of hydrogen peroxide (Asada 1994 Elstner 1990). 

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