Liposomes (lipid, DL-a-dipalmitoyl-phosphatidylcholine) containing chlorophyll a (ratio lipid to chlorophyll 30:1) exhibit an absorption maximum at 670 nm. Upon oxidation with iodine these liposomes yield a chlorophyll radical that shows a ESR signal with a line width (peak to peak) A Y = ~0.1 G and a g-value of 2.0022, consistent with the presence of monomeric chlorophyll. Under anaerobic cond...

In photosynthesis, the pigments chlorophyll a/b absorb light energy to convert to chemical energy in chloroplasts. Though most enzymes of chlorophyll biosynthesis from glutamyl-tRNA to chlorophyll a/b have been identified, the exact composition and regulation of the multimeric enzyme Mg-protoporphyrin IX monomethyl ester cyclase (MPEC) is largely unknown. In this study, we isolated a rice pale-...

The shift in marine resource management from a compartmentalized approach of dealing with resources on a species basis to an approach based on management of spatially defined ecosystems requires an accurate accounting of energy flow. The flow of energy from primary production through the food web will ultimately limit upper trophic-level fishery yields. In this work, we examine the relationship...

Increasing atmospheric carbon dioxide (CO2) concentration could have significant implications on technologies for managing plant nutrition to sustain crop productivity in the future. Soybean ( Glycine max [L.] Merr.) (C3 species) and grain sorghum ( Sorghum bicolor [L.] Moench) (C4 species) were grown in a replicated split-plot design using open-top field chambers under ambient (357 μmol/mol) a...

The response of photosynthetic electron transport and light-harvesting efficiency to high temperatures was studied in the desert shrub Larrea divaricata Cav. Plants were grown at day/night temperatures of 20/15, 32/25, or 45/33 C in rough approximation of natural seasonal temperature variations. The process of acclimation to high temperatures involves an enhancement of the stability of the inte...

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...

in order to evaluate effects of iron, zinc and manganese, and the methods of applying them on yield and yield components of sweet corn (zea mays saccharata), an experiment was performed as factorial based on randomized complete block design with four replications at the research farm of urmia university. experimental factors were micronutrient fertilizers with four levels (control, iron, zinc a...

Water-deficit stresses preferentially reduce shoot growth, thereby disrupting the flow of carbohydrates from source leaves to the developing sinks. Here, we use a novel stress bioassay to dissect responses of field and greenhouse-grown cotton (Gossypium hirsutum) source leaves to water-deficit stresses. Fifth main stem leaf samples were harvested at sunrise and subjected to a prolonged elevated...