In order to study the effect of light competition and microclimatic modifications on the net assimilation (NA), growth and yield of soybean (Glycine max L.) as an understory crop, three 26-year-old soybean-tree (Acer saccharinum Marsh., Populus deltoides X nigra, Juglans nigra L.) intercropping systems were examined. Tree competition reduced photosynthetically active radiation (PAR) incident on...

Photosynthesis limitation by CO2 flow constraints from sub-stomatal cavities to carboxylation sites in chloroplasts under drought stress conditions is, at least in some plant species or crops not fully understood, yet. Leaf mesophyll conductance for CO2 (gm) may considerably affect both photosynthesis and water use efficiency (WUE) in plants under drought conditions. The aim of our study was to...

It is not clear yet how extreme drought and nitrogen (N) deposition influence grassland ecosystem functions when they are considered together, especially in complex field conditions. To explore the response of the Leymus chinensis meadow ecosystem to manipulated extreme drought (45 days), N addition and their interaction, we measured leaf photosynthetic characteristics, aboveground phytomass on...

Increasing concentrations of atmospheric carbon dioxide are expected to affect carbon assimilation and evapotranspiration (ET), ultimately driving changes in plant growth, hydrology, and the global carbon balance. Direct leaf biochemical effects have been widely investigated, whereas indirect effects, although documented, elude explicit quantification in experiments. Here, we used a mechanistic...

In a study on metabolic consumption of photosynthetic electrons and dissipation of excess light energy under water stress, O2 and CO2 gas exchange was measured by mass spectrometry in tomato plants using 18O2 and 13CO2. Under water stress, gross O2 evolution (E(O)), gross O2 uptake (U(O)), net CO2 uptake (PN), gross CO2 uptake (TPS), and gross CO2 evolution (Ec) declined. The ratio P(N)/E(O) fe...

The rates of CO2 assimilation by potted spray carnation plants (cv. Cerise Royalette) were determined over a wide range of light intensities (45-450 W m~ PAR), CO2 concentrations (200-3100 vpm), and leaf temperatures (5-35 °C). Assimilation rates varied with these factors in a way similar to the response of single leaves of other temperate crops, although the absolute values were lower. The opt...

UV-B radiation and EOD light (EOD) quality has both signaling and damaging effects based on the dosage and time of exposure. At highland areas UV-B decreases crop productivity and also light quality increase at high elevation area but EOD light quality effect was not researched based on altitude. Therefore, in the present study a field experiment was conducted to investigate the effects of UV-B...