Changes in dry matter and water-soluble carbohydrate components, especially fructan, were examined in the basal 25 mm of expanding leaf blades of tall fescue (Festuca arundinacea Schreb.) to assess their roles in plant response to water deficit. Water was withheld from vegetative plants grown in soil in controlled-environment chambers. As stress progressed, leaf elongation rate decreased sooner...

Continuous monitoring of steady-state carbon dioxide exchange rates in mature muskmelon (Cucumis melo L.) leaves showed diurnal patterns of photosynthesis and respiration that were translated into distinct patterns of accumulation and phloem export of soluble sugars and amino acids. Leaf soluble sugar patterns in general followed the pattern of photosynthetic activity observed in the leaf, wher...

bemisia tabaci (homoptera: aleyrodidae) is one of the most important pests of cotton in khorasan which causes crop damage and yield reductions as a result of direct feeding of plant and passing pathogenic viruses. using resistant varieties is an economic and environmental friendly method for controlling this pest. the resistance of seven cotton varieties (green leaf okra, red leaf okra, mehr, v...

The effects of shading in combination with salinity treatments were studied in citrus trees on two rootstocks with contrasting salt tolerance to determine if shading could reduce the negative effects of salinity stress. Well-nourished 2-year-old 'Valencia' orange trees grafted on Cleopatra mandarin (Cleo, relatively salt tolerant) or Carrizo citrange (Carr, relatively salt sensitive), were grow...

in order to determine the critical period of weed control and investigation the effect of periodical control and interference of weeds natural population on yield and yield components of winter canola (brassica napus l. cv. okapi) in west region of tehran an experiment was carried out at research field of tarbiat modarres university, tehran, iran on 2004-5 growing season. fourteen experimental ...

The uptake and metabolism of the cytokinin benzyl adenine (BA) was compared in two lines of Petunia hybrida Vilm. differing in their shoot organogenic response. Leaf transfer experiments using shoot induction medium containing 4.4 micromolar BA showed that leaf explants from petunia line St40 required a shoot induction period of 6 to 10 days for commitment to shoot organogenesis; whereas leaf e...

The assimilation of carbon by plant communities (gross primary production [GPP]) is a central concern in plant ecology as well as for our understanding of global climate change. As an alternative to traditional methods involving destructive harvests or time-consuming measurements, we present a simple, general model for GPP as the product of the lifetime carbon gain by a single leaf, the daily l...

an investigation was conducted to determine the genetic diversity among 44 iranian spinach (spinacia oleracea l.) landraces using 21 morphological characteristics under open field conditions. according to data analysis results, significant differences were found among landraces in vegetative traits at 1 and 5% levels. results showed that tabriz landrace had the highest percentage of female plan...