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...

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...

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...

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...

Pumpkin or squash is an economically important crop that moderately sensitive to salinity but how its growth affected by soil poorly understood. Salinity stress on physiological and anatomical traits of Cucurbita moschata ‘Butternut’ was investigated under hydroponic culture using Hoagland’s solution with various NaCl concentrations (0, 25, 50, 75, 100, 150 mM) for four weeks. The results showe...

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 ...

The aim of this study is to evaluate the  effects of water deficit stress on chlorophyll fluorescence (CF) characteristics of photosystem II (PSII) and pigment contents in two rootstock seedlings (Pistacia atlantica L. and P. khinjuk L.). Three levels of soil water potential (Ψs) was used, including WWD (-0.05 MPa), MWD (-0.7 MPa) and SWD (-1.5 MPa). It was found that water stress increased the...

Methyl jasmonate and Epi-brassinolide as plant growth regulators have significant biological effects on plant growth, including increased tolerance to salt stress in plants. In this study, the effects of salinity stress and its interaction with methyl jasmonate and Epi-brassinolide on chlorophyll concentration, rate of photosynthesis, transpiration, stomatal conductance and resistance and chlor...