Sugar beets (Beta vulgaris L.) infected with the Beet Yellows Virus exhibit lower rates of net photosynthesis at light saturation than do healthy plants. These Pn reductions were correlated with increases in leaf resistance to water vapor loss. Theoretical analyses demonstrated that, although the leaf resistance to water vapor loss increases could account for a major part of the net photosynthe...

Effects of moderate heat on growth and photosynthesis were investigated in two clonal genotypes of Acer rubrum L., originally collected from the thermally contrasting habitats of Florida and Minnesota, USA, and known in the horticultural trade for sensitivity and insensitivity to heat, respectively. Under both common garden and warm greenhouse conditions (day/night temperature of 33/25 degrees ...

Net photosynthetic rates of developing foliage and one-year-old foliage of loblolly pine (Pinus taeda L.) were measured under field conditions. In the subsequent year, net photosynthesis and dark respiration rates of current-year and one-year-old foliage were measured under controlled environmental conditions. Loblolly pine foliage grows slowly, reaching its final size 3.5 to 4 months after bud...

Responses of photosynthesis to carbon dioxide (CO2) partial pressure and irradiance were measured on leaves of 39-year-old trees of manuka (Leptospermum scoparium J. R. Forst. & G. Forst.) and kanuka (Kunzea ericoides var. ericoides (A. Rich.) J. Thompson) at a field site, and on leaves of young trees grown at three nitrogen supply rates in a nursery, to determine values for parameters in a mod...

Radiation use efficiency (RUE) provides a useful diagnostic approach for estimating carbon accumulation by terrestrial plant communities. A model for instantaneous gross photosynthesis by a canopy, considering sunlit and shaded leaves, variation of maximum rate of leaf photosynthesis within the canopy and a solution of the radiative transfer equation for propagation of direct and diffuse photos...

The combined effect of selenium (Se) foliar spraying and drought was studied for 3 months in two cultivars of potato; Bard and Adora in Ljubljana, Slovenia. Four combinations of treatments were conducted: well-watered plants with and without Se foliar spraying, and drought exposed plants with and without Se foliar spraying. Net photosynthesis, transpiration rate, quantum yield of photosystem II...

The rate of dark CO(2) efflux from mature wheat (Triticum aestivum cv Gabo) leaves at the end of the night is less than that found after a period of photosynthesis. After photosynthesis, the dark CO(2) efflux shows complex dependence on time and temperature. For about 30 minutes after darkening, CO(2) efflux includes a large component which can be abolished by transferring illuminated leaves to...

Field experiments conducted during the years 2003-2005 showed that the rate of photosynthesis and transpiration decreased as a result of pea infection by Peronospora viciae. Foliar application of effective microorganisms (EM) combined with chemical control increased the rate of photosynthesis in pea, while other methods of EM application reduced net photosynthesis values (An). Chemical control ...

Photosynthesis is a process that indicates the productivity of crops. The estimation this variable can be achieved through methods based on mathematical models. Mathematical models are usually classified as empirical, mechanistic, and hybrid. To mathematically model photosynthesis, it essential to know: input/output variables their units; modeling used its classification (empirical, or hybrid);...

tobacco is a salt-sensitive glycophyte crop species. in this work effect of silicone (si) supplementation (1 mm as na2sio3) was studied in nicotiana rustica l. cv. basmas grown hydroponically in growth chamber under control, low (25 mm) and high (75 mm) nacl concentration for two weeks. dry matter production of leaves was depressed by salinity level as low as 25 mm and higher salt concentration...