this research aimed to evaluate the effect of planting seasons (autumn and spring) on 10 accessions of two species of astragalus effusus and astragalus brachyodontus in the field condition (homand absard station, damavand). after preparing the seedbed, the plant species were planted on two lines in 2 m, where the spacing between the lines of each accession was 0.5 m, and the spacing between the...

The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require informatio...

In monocarpic species, during the reproductive stage the growing grains represent a strong sink for nitrogen (N) and trigger N remobilization from the vegetative organs, which decreases canopy photosynthesis and accelerates leaf senescence. The spatiotemporal distribution of N in a reproductive canopy has not been described in detail. Here, we investigated the role of the local light environmen...

Plant growth regulators (PGRs) are a common and widely used practice in cotton production for controlling plant growth, increasing yield, and improving management efficiency. Most of the PGRs used have an effect on plant growth, both vegetative and reproductive, and dry matter partitioning. However, there have been no reports of effects of PGRs on radiation use efficiency (RUE). It is logical t...

T h e effect of variable tree canopy cover, shadows, and topography on Thematic Mapper (TM) data was examined for blue oak (Quercus douglasii) woodland and wooded grassland on rugged terrain in central California. Thematic Mapper data were analyzed from September 1986 (trees in leaf, grass understory senescent) and December 1984 (trees leafless, grasses emerging. Tree cover measured in 84 60 m ...

Vegetation, soil and ecosystem level carbonyl sulfide (COS) exchange was observed at Duke Forest, a temperate loblolly pine forest, grown under ambient (Ring 1, R1) and elevated (Ring 2, R2) CO 2. During calm meteorological conditions, ambient COS mixing ratios at the top of the forest canopy followed a distinct diurnal pattern in both CO 2 growth regimes, with maximum COS mixing ratios during ...

in other to evaluation of morphological and phenological traits of 24 populations, from four species chamomile of the genus of anthemis, an experiment were carried out using randomized completely blocks design (rcbd) in three replications in alborz research station in karaj, iran during 2011-12. 13 traits including: length and width of canopy diameter, plant height, number of flower, shoot fres...