BACKGROUND Currently established methods to identify viable and non-viable cells of cyanobacteria are either time-consuming (eg. plating) or preparation-intensive (eg. fluorescent staining). In this paper we present a new and fast viability assay for unicellular cyanobacteria, which uses red chlorophyll fluorescence and an unspecific green autofluorescence for the differentiation of viable and ...

The areal development of photosynthetic efficiency and growth patterns in expanding leaves of two different dicotyledonous species - Coccoloba uvifera and Sanchezia nobilis - was investigated by imaging both processes repeatedly over 32 days. Measurements were performed using combined imaging systems for chlorophyll fluorescence and growth, with the same spatial resolution. Significant differen...

Leaf Optical Properties (LOPs) convey information relating to temporally dynamic photosynthetic activity and biochemistry. LOPs are also sensitive to variability in anatomically related traits such as Specific Leaf Area (SLA), via the interplay of intra-leaf light scattering and absorption processes. Therefore, variability in such traits, which may demonstrate little plasticity over time, poten...

Precise measurements of the minimal fluorescence yield (F(o)) and maximal fluorescence yield (F(m)) of a dark-adapted sample are prerequisites for the quantification of other fluorescence parameters. The pulse amplitude-modulated chlorophyll fluorometer (PAM 101 Chlorophyll Fluorometer, Heinz Walz, Effeltrich, Germany) and saturating pulse technique have frequently been used in measuring F(o) a...

To assess photosynthesis as a bioindicator of toxicity from polycyclic aromatic hydrocarbons (PAHs), the response of chlorophyll-a fluorescence to creosote exposure was compared with effects on population-level plant growth. Large, outdoor, freshwater microcosms containing Eurasian watermilfoil (Myriophyllum spicatum) received either a single application or multiple applications of liquid creos...

KO E H N, A.C. (Alabama A&M University, Normal, AL 35762) AND R.L. DOUDRICK (Southern Institute of Forest Genetics, Saucier, MS 39574). Diurnal patterns of chlorophyll fluorescence and CO, fixation in orchard grown Torreya ta.n’jdiu (Am.). Bull. Torrey Bot. Sot. 126:93398. 1999.-Chlorophyll fluorescence and CO, fixation measurements were taken on sunny days in October, 1996, on three Torreyu ta...

BACKGROUND Platelet activation associated with endothelial dysfunction and impaired endogenous platelet inhibition is part of the cardiovascular phenotype of congestive heart failure (CHF) and contributes to the increased risk for thromboembolic complications. Pentaerythritol tetranitrate (PETN) has been shown to release nitric oxide without development of nitrate tolerance. We investigated the...

In this study the variations in surface reflectance properties and pigment concentrations of Antarctic moss over species, sites, microtopography and with water content were investigated. It was found that species had significantly different surface reflectance properties, particularly in the region of the red edge (approximately 700 nm), but this did not correlate strongly with pigment concentr...

It has been claimed that the sole H(2)O(2)-scavenging system in the cyanobacterium Synechococcus sp. PCC 7942 is a cytosolic catalase-peroxidase. We have measured in vivo activity of a light-dependent peroxidase in Synechococcus sp. PCC 7942 and UTEX 625. The addition of small amounts of H(2)O(2) (2.5 microM) to illuminated cells caused photochemical quenching (qP) of chlorophyll fluorescence t...