The photosynthetic and respiratory rates of 5- to 7-year-old aspen stems (Populus tremuloides Michx.) were monitored in the field for 1 year to determine the seasonal patterns. The stem was not capable of net photosynthesis, but the respiratory CO(2) loss from the stem was reduced by 0 to 100% depending on the time of year and the level of illumination as a result of bark photosynthesis. The mo...

In many ecosystem models based on empirical formulations, parameters generally are calibrated in order to achieve the best fit between measured and simulated chlorophyll a standing stocks. An accurate calibration of rate processes as primary production rarely is taken into account. In this paper, we test the usefulness of calibration of phytoplankton photosynthetic processes in an ecosystem mod...

Field experiments conducted during the years 2003-2005 showed that the rate of photosynthesis and transpiration decreased as a result of pea infection by Peronospora viciae. Foliar application of effective microorganisms (EM) combined with chemical control increased the rate of photosynthesis in pea, while other methods of EM application reduced net photosynthesis values (An). Chemical control ...

a factorial experiment based on completely randomized design (crd) was performed with three replications to investigate the interaction between salinity and nh+4 / no-3 ratio on olive saplings. four levels of salinity (0, 50, 100,150 mm) and different ratios of nh+4/ no-3 (0:14, 2:12, 4:10, 6:8) were applied on one-year old olive saplings grown in perlite: sand media (1:1). results indicated th...

The experiments recorded in this paper, dealing with effects of 2537/~ on intact ceils of green algae, were initiated in the hope of gaining more insight into the nature and properties of the catalysts of photosynthesis sensitive to 2537/~; and, possibly by comparison of the sensitivities of the various processes studied, to gain some information as to the relation between them. We have investi...