We compared the morphological and physiological characteristics of understory trees of Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes and Tsuga heterophylla (Raf.) Sarg. growing adjacent to each other in an old-growth forest in southwestern Washington State, USA. We hypothesized that, despite contrasting branching patterns and crown architectures, the two species should exhibit convergenc...

abstract the propose of this study was evaluation of cropsyst model on growth simulation and yield stimation of canola under different irrigation treatments. canola (talaye) was sown under 5 treatment and 4 replicants in completed randomized block designs at the college of agriculture, shiraz universityduring 2007-2008. during the growth season dry mass and lai was meseaured frequently, then mo...

Salt tolerance of higher plants is determined by a complex set of traits, the timing and rate of evolution of which are largely unknown. We compared the salt tolerance of cultivars of sugar beet and their ancestor, sea beet, in hydroponic studies and evaluated whether traditional domestication and more recent breeding have changed salt tolerance of the cultivars relative to their ancestor. Our ...

Koch et al. (Nature 428: 851-854) measured various parameters that were thought to limit the height of Sequoia sempervirens from northern California and concluded that the maximum height for this species is 122-130 m because within this range: (1) Irreversible embolism formation was proposed to occur when the xylem pressure was less than -1.9 MPa. (2) The leaf mass to area ratio exponentially a...

In this study, effect of salinity with different osmotic potential on shoot length, total fresh and dry weight, amounts of organic (proline) and inorganic (K+ and Na+) substance of leaf tissue, the Na+/K+ ratio, and leaf area, relative water content (RWC) and leaf osmolality in two maize (Zea mays L., var. intendata, C.6127 and DK.623) cultivars which are grown as a second yield in the Southeas...

Predicting the effects of climate change on tree species and communities is critical for understanding the future state of our forested ecosystems. We used a fully factorial precipitation (three levels; ambient, -50 % ambient, +50 % ambient) by warming (four levels; up to +4 °C) experiment in an old-field ecosystem in the northeastern USA to study the climatic sensitivity of seedlings of six na...

in order to examine of the weed damage on corn and determination of the most suitable index for corn (zea mays l.) yield reduction in field condition and multi-species weed competition, an experiment as an interval mapping was carried out in the researching field of mashhad university during 2008-2009. treatments were complete control (pre-planting treflan and hand weeding), no control (no herb...

to study the effects of foliar application of common and nano-sized iron sulphate on five sunflower cultivars (alster, olsion, hysun36, yourflour and hysun33) under two levels of salinity (0 and 100 mm nacl), a pot experiment in factorial based using a randomized complete block design with three replications was conducted. plant height, leaf area, shoot weight, chlorophyll content and the conce...

Leaf area index (LAI) is a key structural characteristic of forest ecosystems because of the role of green leaves in controlling many biological and physical processes in plant canopies. Accurate LA1 estimates are required in studies of ecophysiology, atmosphere-ecosystem interactions, and global change. The objective of this paper is to evaluate LA1 values obtained by several research teams us...

We compared smooth-leaf okra- and normal-leaf upland cotton (Gossypium hirsutum L.) strains and cultivars for susceptibility to colonization by Bemisia tabaci (Gennadius) biotype B. Experiments were conducted at seven field sites, five at Holtville, CA, and two at Maricopa, AZ, during 1996-2000. Okra-leaf strains and cultivars, as a group, had lower numbers of adults, eggs, and nymphs compared ...