determined in Scots pine (Pinus sylvestris L.) trees and stands from 7 to about 60 years of age. At the stand scale, leaf area index and net primary productivity (NPP, aboveplus belowground) increased and reached a plateau at about 25--30 and 15--20 years, respectively; both parameters declined in mature stands. Stand hydraulic conductance followed a similar trend to NPP, with a maximum at abou...

Interception of photosynthetically active radiation (PAR) was evaluated relative to greenness and normalized difference [MSS (7 5)/(7 + 5)] for five planting dates of wheat for 1978-79 and 1979-80 at Phoenix, Arizona. Intercepted PAR was calculated from leaf area index and stage of growth. Linear relationships were found with greenness and normalized difference with separate relationships descr...

Light models for vegetation canopies based on the turbid medium analogy are usually limited by the basic assumption of random foliage dispersion in the canopy space. The objective of this paper was to assess the effect of three possible sources of non-randomness in tree canopies on light interception properties. For this purpose, four threedimensional (3-D) digitized trees and four theoretical ...

Leaves are the organs that intercept light and create photosynthesis. Efficient light interception is provided by leaves oriented orthogonal to most of the sun rays. Except in the polar regions, this means orthogonal to the direction of acceleration due to gravity, or simply horizontal. The leaves of almost all terrestrial plants grow in a gravity field that tends to bend them downward and ther...

We examined the effects of artificially altering leaf angle of the tropical tree species Acacia crassicarpa (A. Cunn. ex Benth., Fabaceae) on light interception, leaf temperature and photosynthesis in the wet and dry seasons of tropical Australia. Reducing leaf angle from the natural near-vertical angle (90 degrees ) to 67.5, 45, 22.5 and 0 degrees greatly increased light interception and leaf ...

BACKGROUND Although plant diversity is postulated to resist invasion, studies have not provided consistent results, most of which were ascribed to the influences of other covariate environmental factors. METHODOLOGY/PRINCIPAL FINDINGS To explore the mechanisms by which plant diversity influences community invasibility, an experiment was conducted involving grassland sites varying in their spe...

To further development of a simplified fertigation system using controlled-release fertilizers (CRF), we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI), fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS), summer-fall (SF), and fall-winter (FW) seasons. Pl...

to investigate the effect of plant density and supplemental irrigation on agronomic characteristics, chlorophyll content and light interception beneath the canopy of three chickpea genotypes under dryland conditions, an experiment was conducted at research station of lorestan agricultural research center located at chegini, khoramabad, during 2004-2005. the study was conducted using a split-spl...

The effect of two training systems (Central Leader with branch pruning versus Centrifugal Training with minimal pruning, i.e., removal of fruiting laterals only) on canopy structure and light interception was analyzed in three architecturally contrasting apple (Malus domestica Borkh.) cultivars: 'Scarletspur Delicious' (Type II); 'Golden Delicious' (Type III); and 'Granny Smith' (Type IV). Tree...