Photosynthetic performances

More recent studies have documented the occurrence of a specific U VB-absorbing compound with an absorption maximum at 294 nm in the green macroalga Ulva pertusa (Han and Han 2005). UVB-radiation strongly induced this compound and its accumulation resulted in a higher photosynthetic performance under U V exposure,... 

Karsten U, Bischof K, Wiencke C (2001) Photosynthetic performance of Arctic macroalgae after transplantation from deep to shallow waters followed by exposure to natural solar radiation. Oecologia 127 11-20... 

Michler T, Aguilera J, Hanelt D, Bischof K, Wiencke C (2002) Long term effects of ultraviolet radiation on growth and photosynthetic performance of polar and cold-temperate marcoalgae. Mar Biol 140 1117-1127... 

Keiller DR, Holmes MG (2001) Effects of long-term exposure to elevated UV-B radiation on the photosynthetic performance of five broad-leaved tree species. Photosynth Res 67 229-240 Kogami H, Hanba YT, Kibe T, Terashima I, Masuzawa T (2001) C02 transfer conductance, leaf structure and carbon isotope composition of Polygonum cuspidatum leaves from low and high altitudes. Plant Cell Environ 24 529-538... 

Fig. 2. Annual atmospheric C02-concentration measured at Mauna Loa Observatory, Hawaii. Fluctuations originate from seasonal photosynthetic performance (taken from Ref. [14])...

Figure 37.4 Replicate Pseudo-nitzschia multiseries cultures were grown under 24 h light (100 tmol photons s ) at 15 °C for 4 days as an auxostat (chemostat with growth limited by pump rate) with Si-limited f/2 media. On day -4, the pumps were turned off, forcing the cultures into Si-limitation. On days 0, 4 Si-spikes (10 pM) were added. On day 5, trace-metals (f/2 stock) was added, with no apparent response. Optical density (cell abundance) and variable fluorescence were determined from a PAM fluorometer and are plotted versus time (dashed vertical lines indicate additions of unenriched seawater dashed horizontal line indicates maximal Fv/Fm values in healthy cells). A rapid decline and recovery of variable fluorescence indicates impaired photosynthetic performance, and functionally mimics the response of Fe-limitation, with recovery times dependent on the length of time spent in Si-deprived conditions.

Lippemeier, S., Hartig, P., and CoHjn, F. (1999). Direct impact of silicate on the photosynthetic performance of the diatom Thalassiosira weissjlogii assessed by on- and off-line PAM fluorescence measurements.y. Plankton Res. 21, 269—283. 

Super-RuBisCO Improvement of photosynthetic performances of plants... 

A batch culture or a semi-batch culture was investigated to determine the photosynthetic performance under outdoor culture conditions. An air/CO2(10% COj) mixture(C02 enriched air) was injected into the two pathway of the HTP at a total flow rate of 1.2 litre / min. The optical density of the culture medium at 750 nm was measured and the biomass concentration was calculated using a standard curve between biomass concentration(dry weight) and optical density. The carbon content of the biomass was analyzed by a C/N analyzer in order to calculate the caloric value. 

Over-expressed effect of carbonic anhydrase (CA) on CO2 fixation in cyanobacterium, Synechococcus sp. PCC7942, was evaluated. CA overexpression in carboxysomes induced elevated levels of growA rate and CO2 fixation rate, suggesting the possibility to improve photosynthetic performance. 

In order to clarify the effect of over-produced CA in carboxysomes on photosynthetic performances, growth rate and CO2 fixation rate were evaluated. CA over-expressed transformants when cultured under the CO2 concentration in the air, showed elevated levels of growth rate comparing with wild type or vector-control strains. This effect was enhanced as Ae aeration rate was decreased or under the concentration of 20ppm CO2 in the culture (Fig.4), suggesting that over-expressed CA is especidly important vmder the limited supply of DIC. 

The enhanced CO2 fixation rate in the transformants was further confirmed under the concentration of 20ppm CO2 in the culture, using independent eleven clones of CA over-expressed transformants and five vector-control clones. As a result, CA over-expression induced elevated levels of CO2 fixation rate, suggesting the possibility to improve photosynthetic performances (Fig. 5). 

Dandelions Taraxacum officinale, Asteraceae), a well known weed from temperate to tropical climates (Holm et al., 1997), is one of several alien species that have colonized the high Andes from Venezuela to Chile, especially in areas under anthropogenic disturbance. A recent study investigated the association of dandelions introduced from Europe with the cushion plant Azorella monantha (Apiaceae) between 3100 and 3300 asl with reference to survival facilitation of dandelion seedlings, their effect on native species growing on the invaded cushions, and photosynthetic performance (Cavieres et al., 2005). 

Bigot A., Fontaine F., Clement C., Vaillant-Gaveau N. Effed of the herbicide flumiox-azin on photosynthetic performance of grapevine (Vitis vinifera L.). Chemosphere 2007 67(6) 1243-1251. 

A. Flores-Moya, I. Gomez, B. Vinegla, M. Altamirano, E. Perez-Rodriguez, C. Maestre, R.M. Caballero, F.L. Figueroa (1998). Effects of solar radiation on the endemic Mediterranean red alga Rissoella verruculosa photosynthetic performance, pigment content and the activities of enzymes related to nutrient uptake. New Phytol, 139, 673-683. 

D.-P. Hader, M. Lebert, E.W. Helbling (2000). Photosynthetic performance of the chlorophyte Ulva rigida measured in Patagonia on site. Rec. Res. Develop. Photochem. Photobiol, 4,259-269. 

The photosynthetic performance of the mutant does not change significantly under non-stress light conditions. However, the major LHCII isolated from this mutant appears less stable, as it dissociates more easily from the trimeric to the monomeric state and also into protein and unbound pigments (Tardy and Havaux, 1996). It may be this reduced amount and/or the reduced stability of trimeric LHCII in the aba mutant that is responsible for its reduced thylakoid stacking (Rock et al., 1992). 

Lers A, Heifetz PB, Boynton JE et al. The carboxyl-terminal extension of the D1 protein of photosystem II is not required for optimal photosynthetic performance under C02- and light-saturated growth conditions. J Biol Chem 1992 267 17494-17497. 

Z.S. Kolber, Laser Induced Fluoreseence Transient (LIFT) Method for Measuring Photosynthetic Performance and Primary Productivity in Terrestrial Eeosystems, Earth Science Teehnology Conference, Paper B1P2, Pasadena, California (2002)... 

The increases in amounts of PSII and LHCII (Table 1) presumably improve the capacity of the shade plant to harvest light relative to the sun plant when light intensities are low. Consequently, the changes in thylakoid composition initiated by changes in the light environment are such that the photosynthetic performance of the plant is optimised for that particular light... 

Tab. 2. Comparative photosynthetic performance of Qommia and Tradescantia at elevated and near atmospheric CO2 concentrations (Figs. 1 and 3).

The initial indication that growth could be severely retarded in the RHA 273 cultivar of sunflower without effects on photosynthetic performance was that in situ CO2 fixation and stomatal conductance were identical in plants at 10 and 100 mM NaCl after two weeks of treatment. Under growth chamber conditions, the average values for leaves 3 to 8 were 20 /tmol CO2 m s ... 

ORT D., AHRENS W.. MARTIN B. STOLLER E. (1983) Comparison of photosynthetic performance in triazine-resistant and susceptible biotypes ot Amaranthus hvbridus. - Plant Phvsiol. 72. 925-930. 

Schliiter, U., Muschak, M., Berger, D. Altmann, T. (2003). Photosynthetic Performance of an Arabidopsis Mutant with Elevated Stomatal Density (sddl-1) Under Different Light Regimes. Journal of Experimental Botany, Vol.54, No.383, (February 2003), pp. 867-874. 

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