Abstract In order to evaluate the effects of drought stress and defoliation on sunflower, a study was conducted under controlled conditions. Treatments were a combination of three levels of drought ((100, 60 and 30 percent of Field Capacity (FC)) and three levels of defoliation (control, removal of either 4 or 6 leaves from lower part of the plant) laid out, in a Completely Randomized Design w...

AIMS The objective of the study was to characterize variations in proline, arginine, histidine, vegetative storage proteins, and cold-inducible gene expression in overwintering roots of field-grown alfalfa, in response to autumn defoliation, and in relation to spring regrowth and winter survival. METHODS Field trials, established in 1996 in eastern Canada, consisted of two alfalfa cultivars (...

During repetitive defoliation events, carbon can become limiting for trees. To maintain growth and survival, the resources have to be shared more efficiently, which could result in a trade-off between the different physiological processes of a plant. The objective of this study was to assess the effect of defoliation in carbon allocation of balsam fir [Abies balsamea (L.) Mill.] to test the pre...

BACKGROUND Plant leaves, as the main photosynthetic organs and the high energy converters among primary producers in terrestrial ecosystems, have attracted significant research attention. Leaf lifespan is an adaptive characteristic formed by plants to obtain the maximum carbon in the long-term adaption process. It determines important functional and structural characteristics exhibited in the e...

A study concerning the effects of elevation and exposure of the spruce forests on defoliation levels of oriental spruce (Picea orientalis (L.) Link.) by Ips typographus L. was carried out during 2005 and 2006 in Artvin-Hatila National Park, Turkey Nine spruce stands were selected at 3 zones of elevations (1000-1350 m, 1350-1700 m and 1700-2000 m) and at different aspects to assess the role of e...

BACKGROUND AND AIMS Grazing is a complex process involving the simultaneous occurrence of both trampling and defoliation. Clonal plants are a common feature of heavily grazed ecosystems where large herbivores inflict the simultaneous pressures of trampling and defoliation on the vegetation. We test the hypothesis that physiological integration (resource sharing between interconnected ramets) ma...

Growth rate varies widely among species and the trade-off between growth rate and storage or maintenance traits is a principal axis of variation between species. Many plant species have substantial root stores, but very little is known about how growth rate modifies responses of these stores to defoliation and other stresses. Species with different growth rates are predicted to respond in disti...

J. Eoon. Entomol. 73: 369-373 (1980) Potato plots were partially defoliated by populations of Leptinotarsa decemlineata (Say) to learn how insect defoliation affected potato yields. The experiment was repeated 7 times at 2·wk intervals throughout the season to determine how plant sensitivity to defoliation changed with plant development. The percent yield reduction of defoliated rows was regres...

Insect defoliation is a major disturbance force in forbetween 1987 and 1993, but single date NIR in each year was negatively correlated with budworm levels in 1993 ested ecosystems. Monitoring outbreaks, and estimating (r520.69 and 20.47). This was because hardwood trees the areas affected, is therefore important for both forest within jack pine stands caused higher NIR reflectance managers and...

Effects of a mixture of the postemergence herbicides acifluorfen and bentazon, and simulated defoliation expected from green cloverworm on population densities of Heterodera glycines were determined in field plots in Iowa. The herbicide mixture and defoliation each suppressed soybean growth. Population densities of H. glycines were generally lower in herbicide-treated than untreated plots. Popu...