A bio-optical mooring, which was deployed for 240 days during 1987 in the western Sargasso Sea (-35øN, 70øW), provided among other things a detailed record of the seasonal distribution of chlorophyll a fluorescence and the scalar irradiance of photosynthetically available radiation. This data base was augmented by shipboard measurements of chlorophyll a concentration, chlorophyll a fluorescence...

Several photochemical and spectral properties of maize (Zea mays) bundle sheath and mesophyll chloroplasts are reported that provide a better understanding of the photosynthetic apparatus of C(4) plants. The difference absorption spectrum at 298 K and the fluorescence excitation and emission spectra of chlorophyll at 298 K and 77 K provide new information on the different forms of chlorophyll a...

Recently disturbed and ‘control’ (i.e. less recently disturbed) soils in the Mojave Desert were compared for their vulnerability to wind erosion, using a wind tunnel, before and after being experimentally trampled. Before trampling, control sites had greater cyanobacterial biomass, soil surface stability, threshold friction velocities (TFV; i.e. the wind speed required to move soil particles), ...

abstract in order to investigate the effects of nitrogen fertilizer levels on the yield and quality of potato, (solanum tuberosum l.) a field experiment was conducted based on randomized complete blocks design with 3 replications in the research field of the college of agriculture, ferdowsi university of mashhad. nitrogen topdress fertilizer was applied in two levels of 100 and 150 kgn.ha-1 and...

studying the physiological responses of linseed genotypes to water deficit stress may be helpful in recognizing the linseed resistance mechanisms to the latter stress factors. therefore, a split plot rcbd field experiment was conducted with three replications to explain interrelations of leaf chlorophyll, proline and soluble carbohydrates content and grain yield of six linseed genotypes under t...

cold is one of the most important abiotic stresses in some regions of iran. to investigate of some tolerance related traits to cold condition, 22 bread wheat genotypes planted in ardabil region in 1980. after plants passed winter cold condition (135 freezing days), cell membrane stability, chlorophyll content of leaf and crown depth and grain yield of genotypes were measured. anova analysis sho...