The use of LED technology is commonly assumed to result in significantly cooler leaf 1 temperatures than high pressure sodium technology. To evaluate the magnitude of this 2 effect, we measured radiation incident to and absorbed by a leaf under four radiation 3 sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants 4 under either high pressure sodium or ligh...

The role of landscape topography in mediating subsurface water availability and ultimately tree transpiration is still poorly understood. To assess how hillslope position affects use, we coupled sap velocity with xylem isotope measurements a temperate beech-oak forest along transect Luxembourg. We generally observed greater velocities at the upslope locations trees from average-sized trees, sug...

Among the plant factors, canopy geometry plays a crucial role in deciding the driving force for leaf biological processes since it modulates canopy interception of short-term radiation fluxes and it controls their distributions throughout the foliage (Monteith and Unsworth, 1990; Jones, 1992). In particular, it is recognized the biological role of PhAR (400-700 nm waveband) in driving the photo...

A scanning, volume-imaging Raman lidar was used in August 1997 to map the water vapor and latent energy flux fields in southern Arizona in support of the (Semi-Arid Land Surface Atmosphere) SALSA program. The SALSA experiment was designed to estimate evapotranspiration over a cottonwood riparian corridor and the adjacent mesquite-grass community. The lidar derived water vapor images showed micr...

The effects of four concentrations (25, 50, 75, 100%) of spinach homogenate filtrate over a period of 96 hours on the body mass and transpiration rates of the pulmonate slug Milax rusticus, a crop pest found in Benghazi, Libya, are reported. A decrease in body mass and transpiration rate in filtrate treated slug over time was evident and the differences in these factors between control and trea...

The photosynthetic rate increases under high-N supply, resulting in a large CO₂ transport conductance in mesophyll cells. It is less known that water movement is affected by nitrogen supply in leaves. This study investigated whether the expression of aquaporin and water transport were affected by low-N (0.7 mM) and high-N (7 mM) concentrations in the hydroponic culture of four rice varieties: (...

The influence of red light and ultraviolet (UV)-A radiation on the single leaf photosynthesis and transpiration were investigated in two different plant-type rice cultivars: active tillering type, Hopumbyeo (HP) and low-tillering heavy panicle type, Shindongjinbyeo (SDJ) at maximum tiller number stage. An open photosynthesis measurement system was used to monitor CO2 exchange rate, which was de...

[1] The Penman-Monteith equation is often used to estimate transpiration, but an important limitation to this approach, especially for mountainous forested sites, is an accurate estimate of canopy conductance averaged over the area of interest (Gs). We propose a method for estimating watershed-scale transpiration using estimates of Gs derived from measurements of stable isotopes. To estimate Gs...

In this paper we begin our study of factors controlling Na* and K* uptake in the halophyte Spergularia marina (L.) Griseb., with emphasis on plants growing at moderate salinity (0.2x sea water). The involvement of transpiration was considered first because of its potential to account for much or all of the transport of ions, and particularly of Na*, to the shoot under these growth conditions. T...