Net photosynthetic rate, CO(2) compensation concentration, and starch and soluble sugar concentrations were measured in soybean (Glycine max [L.] Merrill) leaves in an attempt to evaluate the effect of carbohydrate concentration on rate of CO(2) assimilation.Plants were grown in a controlled environment room at 23.5 C, 50% relative humidity, 16-hour photoperiod, and quantum flux (400-700 nm) of...

The time-course of CO(2) assimilation rate and stomatal conductance to step changes in photosynthetic photon flux density (PPFD) was observed in Chrysanthemum x morifolium Ramat. ;Fiesta'. When PPFD was increased from 200 to 600 micromoles per square meter per second, the rate of photosynthetic CO(2) assimilation showed an initial rapid increase over the first minute followed by a slower increa...

Variations in leaf nitrogen concentration per unit mass (Nm) and per unit area (Na), mass-to-area ratio (Ma), total nonstructural carbohydrates (Ta), and photosynthetic capacity (maximum carboxylation rate, electron transport capacity, rate of phosphate release in triose phosphate utilization and dark respiration rate) were studied within the digitized crowns of two 3-year-old mango trees (Mang...

Pine wilt disease (PWD) is considered as the most destructive forest-invasive alien species in China. We measured gas exchange parameters and foliar carbon isotope ratios (δ13C) of different infection phases of Masson pine in order to investigate the effect of Bursaphelenchus xylophilus infection on photosynthetic responses and resource-use efficiency. The results showed that net photosynthetic...

The photosynthetic leaf characteristics of two rose species native to Japan were measured. The optimum temperature range for photosynthesis of Rosa bracteata was higher than that of Rosa rugosa. The photosynthetic response to temperature of R. bracteata was slower than that of R. rugosa. Maximum photosynthetic rates were reached at an irradiance of higher than 750 m mol mÿ2 sÿ1 in both species....

We set up a free-air ozone (O(3)) exposure system for determining the photosynthetic responses of Siebold's beech (Fagus crenata) and oak (Quercus mongolica var. crispula) to O(3) under field conditions. Ten-year-old saplings of beech and oak were exposed to an elevated O(3) concentration (60 nmol mol(-1)) during daytime from 6 August to 11 November 2011. Ozone significantly reduced the net pho...

The physiological responses of 6- to 8-year-old aspen (Populus tremuloides Michx.) stems to temperature, light, and CO(2) concentration were investigated in the field throughout the year using infrared CO(2) analysis. Light response studies showed that the rate of gross photosynthesis was linear from 0 to 400 ft-c (0 to 1.6 mw/cm(2) of 400-700 nm) with light saturation being reached between 800...

Ascorbic acid (Asc) is a major antioxidant in plants that detoxifies reactive oxygen species (ROS) and maintains photosynthetic function. Expression of dehydroascorbate reductase (DHAR), responsible for regenerating Asc from an oxidized state, regulates the cellular Asc redox state, which in turn affects cell responsiveness and tolerance to environmental ROS. Because of its role in Asc recyclin...

Midday depression of photosynthesis has important consequences for ecosystem carbon exchange. Recent studies of forest trees have demonstrated that latent reduction of photosynthetic capacity can begin in the early morning, preceding the midday depression. We investigated whether such early morning reduction also occurs in an herbaceous species, Oenothera biennis. Diurnal changes of the photosy...