Trade-offs associated with maintaining herbivory resistance and herbivory tolerance are frequently inferred in plant life histories. Invasive success for many non-native plants is often attributed to novel resistance that repels native herbivores. Chinese tallow tree (Sapium sebiferum, Euphorbiaceae) is a non-native invader that threatens ecosystems throughout the southeastern United States, in...

Previous studies have indicated that an increased asparagine to glutamine ratio (Asn : Gln) occurs in the xylem fluid of Lolium perenne 24 h after defoliation. However, the absolute changes in Asn and Gln leading to the increased Asn : Gln ratio are unknown. The present study tested the hypotheses that: (1) defoliation-induced changes in xylem amino acid composition occur in L perenne within th...

studies on manipulating the source-sink relationships during postanthesis in wheat have shown inconsistent results, concluding that wheat yield could be either sink- or source-limited. most studies have reported data of grain mass as an average of all grains preventing the recognition of different sensitivities to the availability of assimilates of grains placed at different positions within th...

The impact of different levels of whole plant partial defoliation (WPPD) on the photosynthesis andprimarymetabolismofwheat,TriticumaestivumL.,was evaluatedat thevegetative and reproductive (grain-Þlling) developmental stages. Photosynthetic parameters such as photosynthesis, stomatal conductance, and transpiration, chlorophyll a ßuorescence, and plant morphological parameters, such asmain stemh...

Registered, multi temporal Landsat data of a study area in central Pennsylvania were analyzed to detect and assess changes in the forest canopy resulting from insect defoliation. Images taken July 19, 1976, and JUne 27, 1977, were chosen specifically to represent forest canopy conditions before and after defoliation, respectively. Several image manipulation and data transformation techniques, d...

To understand the responses to external disturbance such as defoliation and possible feedback mechanisms at global change in terrestrial ecosystems, it is necessary to examine the extent and nature of effects on aboveground-belowground interactions. We studied a temperate heathland system subjected to experimental climate and atmospheric factors based on prognoses for year 2075 and further expo...

to evaluate the effects of sowing density, deferred harvesting, and harvest intensity on forage yield and an some vegetative characteristics of annual medic (medicago scutelatta var robinson) an experiment was conducted on the research farm of college of agriculture ,university of tehran ,karaj, during 2005 growing season. the expremental treatments were arranged in split-split plots based on a...