background and objectives: active coal is applied in tissue culture media as the absorbant of phenolic compounds and toxic materials; but no research has been done regarding its direct application like spray on plants. application of this material as the carbone source is based on researches done by sucrose; which had highly positive effect on plant growth and development. thus; a hypothesis wa...

Cyanobacteria are ecologically important photosynthetic prokaryotes that also serve as popular model organisms for studies of photosynthesis and gene regulation. Both molecular and ecological studies of cyanobacteria benefit from real-time information on photosynthesis and acclimation. Monitoring in vivo chlorophyll fluorescence can provide noninvasive measures of photosynthetic physiology in a...

Temporal changes in gas exchange and chlorophyll fluorescence of Paeonia suffruticosa seedlings acclimated to three levels of light environments were investigated. There was a significant photosynthetic depression in seedlings acclimated to a long time of shading and then suddenly exposed to full ambient radiation. The decreased transpiration (E ) resulted from ‘feed-forward effect’ mechanism [...

Under high nutrient concentrations and sufficient light conditions, large phytoplankton may display higher photosynthetic efficiency than smaller cells. This is unexpected since smaller phytoplankton, because of their higher surface to volume ratio, possess a greater ability to take up nutrients and absorb light. In order to investigate the causes of the increased photosynthetic efficiency in l...

To reveal and quantify the interactive effects of drought stresses and elevated CO2 concentration [CO2] on photochemistry efficiency of cucumber seedlings, the portable chlorophyll meter was used to measure the chlorophyll content, and the Imaging-PAM was used to image the chlorophyll fluorescence parameters and rapid light response curves (RLC) of leaves in two adjacent greenhouses. The result...

This study was carried out in a plantation of a degraded area in Central Amazon, Brazil, in order to assess environmental light effects on leaf pigment concentrations and chlorophyll a fluorescence in mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Aubl. Willd). Three-year old saplings were grown in an open site (sun) with maximum radiation of approximately 2000 μmol m s ...

high temperature, high radiance, low vapor pressure, and lack of precipitation in most months characterize arid ecosystems. under these conditions, tree crops such as pistachio suffer from drought combined with salinity stress. in order to investigation effects of combined salinity and drought stress on function of photosynthetic apparatus, mutica pistachio (pistacia mutica) seedlings were subj...

The temperature dependence of the relationship between the decline in activity of photosystem II (PSII) and a chlorophyll a fluorescence parameter combining the excitation pressure (1-qP) and efficiency of excitation energy capture by open PSII reaction centers in the light-acclimated state (Fv'/Fm') was investigated in cotton leaves. A formula for the prediction of PSII inactivation is propose...

chlorophyll fluorescence induction is a rapid and noninvasive technique for measuring photosynthetic electron transport in plants. chlorophyll fluorescence measurements were performed under greenhouse condition to characterize how the fluorescence induction curves (kautsky curve) and its parameters were affected by metribuzin in susceptible and resistant junglerice (echinochloa colona (l.) link...