The dissipation of absorbed light and potential for photooxidative damage was explored in Douglas-fir (Pseudotsuga menziesii ) seedlings with and without Phaeocryptopus gaeumannii infection. The presence of P. gaeumannii significantly reduced net CO2 assimilation rates from ca. 6 lmol/m/s to 1.5 lmol/m/s, without any significant impact on chloroplast pigments. The partitioning of absorbed light...

Herein we extend prior studies of biosynthetic strontium replacement of calcium in PSII-WOC core particles to characterize whole cells. Previous studies of Thermosynechococcus elongatus found a lower rate of light-saturated O2 from isolated PSII-WOC(Sr) cores and 5-8× slower rate of oxygen release. We find similar properties in whole cells, and show it is due to a 20% larger Arrhenius activatio...

The study examines the transfer factor (TF) for cesium in a soil-plant system and cesium accumulation in cress Lepidium sativum L. plants grown in hydroponic culture and subjected to root and foliar application of 0.3 mM CsCl. The experiments showed a high TF for radiocesium: 2.97 (kBq/kg plant DW)/(kBq/kg soil DW). High accumulation of cesium was observed in leaves after both root and foliar t...

Microalgal lipid is one of the most promising feedstocks for biodiesel production. Chlorella appears to be a particularly good option, and nitrogen (N) starvation is an efficient environmental pressure used to increase lipid accumulation in Chlorella cells. The effects of N starvation of an oil-producing wild microalga, Chlorella sorokiniana C3, on lipid accumulation were investigated using thi...

Chlorophyll-a fluorescence induction is a rapid technique for measuring photosynthetic electron transport in plants. To assess chlorophyll-a fluorescence as a bioindicator of effects of polycyclic aromatic hydrocarbon mixtures, chlorophyll-a fluorescence parameters and plant growth responses to exposure to the wood preservative creosote were examined in the aquatic plants Lemna gibba and Myriop...

The effect of jasmonic acid on PSII reactions was assessed by changes in kinetic characteristics of O2 evolution and thermoluminesce glow curves in barley leaves and isolated thylakoid membranes. In comparison to the control preparation, JA-treated samples showed reduced efficiency in the utilization of oxidizing equivalents generated at PSII reaction centres and retardation of S-state transiti...

Second year needles of Lodgepole pine (Pinus contorta L.) were exposed for 6 weeks to either simulated control summer ['summer'; 25 °C/250 photon flux denisty (PFD)], autumn ('autumn'; 15°C/250 PFD) or winter conditions ('winter'; 5 °C/250 PFD). We report that the proportion of linear electron transport utilized in carbon assimilation (ETR(CO2)) was 40% lower in both 'autumn' and 'winter' pine ...

The phototolerance of three chlP transgenic tobacco (Nicotiana tabacum) lines, affected in geranylgeranyl reductase and, hence, deficient in tocopherols (vitamin E), was estimated by in vivo luminescence and fluorescence measurements and was compared with that of the wild type (WT). Exposure of leaf discs to high light (1 mmol photon m(-2) s(-1)) and low temperature (10 degrees C) led to a rapi...

Although the kinetic chlorophyll fluorescence signals are rich in information, most of the chlorophyll fluorescence related studies deal only with the quantum yield of primary photochemistry (Fv/Fm). JIP-test based OJIP fluorescence transient analysis is relatively a new technique to investigate the environmental stress responses of photosynthetic organisms. In the present study, the deleteriou...

Some ploidy plants demonstrate environmental stress tolerance. Tetraploid (4×) black locust (Robinia pseudoacacia L.) exhibits less chlorosis in response to high CO 2 than do the corresponding diploid (2×) plants of this species. We investigated the plant growth, anatomy, photosynthetic ability, chlorophyll (chl) fluorescence, and antioxidase activities in 2× and 4× black locusts cultivated und...