investigating the role of drought stress conditions on physiological characteristics of plant may provide means to understand basic drought resistance. differences in leaf emergence rate, leaf relative water content (rwc), membrane stability index (msi), leaf mass area (lma), net photosynthesis (anet), stomatal conductance (gs), transpiration rate (e), intercellular co2 concentration (ci), ...

many phragmites-dominated wetlands have been markedly salinized and alkalinized in the songnen plain, northeastern china. agricultural wastewater with high nitrogen content has been discharged into these alkalinized-salinized wetlands. to understand the effect of salinity-alkalinity on reed (phragmites australis) seedlings at various nitrogen levels, we examined photosynthesis rate, chlorophyll...

OBJECTIVE To compare gas exchange at rest and during exercise in patients with chronic Chagas' heart disease grouped according to the Los Andes clinical hemodynamic classification. METHODS We studied 15 healthy volunteers and 52 patients grouped according to the Los Andes clinical and hemodynamic classification as follows: 17 patients in group IA (normal electrocardiogram and echocardiogram),...

Whole-plant photosynthetic rate of rose (cv. Kardinal) was measured with an open system consisting of a computer-controlled data acquisition system and an infrared gas analyzer (IRGA). The system was used to monitor diurnal patterns of whole-plant gas exchange in response to environmental variables and a model to simulate this was constructed. A model for leaf photosynthesis was calibrated and ...

the purpose of this research is investigation of application of the arbitrage pricing theory and effect of unanticipated changes in a set of macroeconomic variables such as inflation rate, money supply, exchange rate, oil price, term structure and industrial production on expected security return in tehran stock exchange. in this research, data are analyzed quarterly for the period of 1997-2008...

The mechanisms governing pulmonary gas exchange were heavily debated at the start of the 20th century when Christian Bohr provided measurements of lung and blood gases as well as rational arguments in favour of oxygen being secreted actively from the lung gas to the blood within vertebrate lungs. The concept of active transport was studied by August Krogh in his doctoral dissertation on the par...

A lumped two-compartment mathematical model of respiratory mechanics incorporating gas exchange and pulmonary circulation is utilized to analyze the effects of square, descending and ascending inspiratory flow waveforms during mechanical ventilation. The effects on alveolar volume variation, alveolar pressure, airway pressure, gas exchange rate, and expired gas species concentration are evaluat...

Insects breathe through valved openings (spiracles) in their cuticle. Many insects open and close their spiracles in a cyclic pattern (discontinuous gas-exchange cycles, or DGC). These cycles were observed over half a century ago, their hypothesized function being to minimize loss of water from the tracheal system. However, numerous recent studies have found that respiration accounts for a smal...