Biogeochemical processes in plants, such as photosynthesis, evaporation and net primary production, are directly related to foliar water. Therefore, canopy water content is important for the understanding of the terrestrial ecosystem functioning. Spectral information related to the water absorption features at 970 nm and 1200 nm offers possibilities for deriving information on leaf and canopy w...

Phosphorus is known to be exported from leaves of apple (8, 9, 10), bean (4, 6, 11, 12, 13), chrysanthemum (1, 2), corn (11, 12), tomato (12) and squash (71). The present work with bean plants compares export following application by spray, leaf vein injection (4) and droplet (13) methods. Other factors investigated which affect absorption and subsequent translocation of the spray-applied phosp...

The amount of photosynthetically active radiation (PAR) absorbed by a canopy (APAR) is an important driving variable for vegetation processes such as photosynthesis. PAR extinction in clumped canopies of shortgrass ecosystems is the focus of this paper. Directional gap fractions estimated at peak biomass on several Mexican shortgrass ecosystems with a hemispherical radiation sensor (Li-Cor, LAI...

PROSPECT, a widely-used leaf directional-hemispherical reflectance and transmittance model, currently treats the behaviour of chlorophylls a, b, carotenoids, and anthocyanins uniformly, leading to errors. A finer discrimination among these pigments in lightabsorbing plant tissues should improve the model. In this paper, a new calibration and validation phase of PROSPECT is performed using two c...

Humic acid is a biochemical constituent of humus and increases root biomass and shoot growth by improving absorption of nutrients. In order to study the effects of humic acid on root and shoot growth and leaf nutrient contents of pistachio seedlings, an experiment was conducted of completely randomized design with five treatments in three replications. In the first step seeds of Pistacia vera c...

Canopy water content is a dynamic quantity that depends on the balance between water losses from transpiration and water uptake from the soil. Absorption of shortwave radiation by water is determined by various frequencies that match overtones of fundamental bending and stretching molecular transitions. Leaf water potential and relative water content are important variables for determining wate...

The optical properties of leaves from five species, Norway maple (Acer platanoides L.), cotoneaster (Cotoneaster alaunica Golite), hazel (Corylus avellana L.), Siberian dogwood (Cornus alba L.), and Virginia creeper (Parthenocissus quinquefolia (L.) Planch.), differing in pigment composition and at different stages of ontogenesis, were studied. Anthocyanin absorption maxima in vivo, as estimate...

salinity stress results to decreasing leaf area index (lai) and light absorption in plant leading in yield decrease. in order to study effect of salinity and iron sulphate on lai, absorbed light percentage and yield of sunflower (euroflor cultivar), an experiment was carried out as split plot based on complete randomized block design with four replications in the research field of university of...

Studies were initiated to evaluate absorption, translocation, and distribution of C-quinclorac in propaniland quinclorac-resistant (R-BYG) and -susceptible (S-BYG) barnyardgrass. No differential absorption of C-quinclorac was observed between R-BYG and S-BYG, but more C remained in the treated leaf of S-BYG (57% of total absorbed) compared with the R-BYG leaf (34% of total absorbed) at 72 h aft...

[1] A large increase in near-infrared (NIR) reflectance of Amazon forests during the light-rich dry season and a corresponding decrease during the light-poor wet season has been observed in satellite measurements. This increase has been variously interpreted as seasonal change in leaf area resulting from net leaf flushing in the dry season or net leaf abscission in the wet season, enhanced phot...