studies manipulating the source-sink relationships during post anthesis in wheat have shown inconsistent results, concluding that wheat yield could be either sinkor source-limited. the aim of this study was to determine source limitation degree of 36 iranian wheat cultivars andto investigate their intrinsic compensatory mechanism in response to source size reduction. a split plot design based o...

Harvesting nontimber forest products (NTFPs) is a major economic activity in tropical forests. As many NTFPs are overexploited, sustainability analyses are required to set harvest guidelines. Here we introduce and apply a new approach to evaluating sustainability, which combines prospective (elasticity) and retrospective (Life Table Response Experiments [LTRE]) demographic analyses of matrix po...

The interaction between insect outbreaks and forest health or tree plantation management has been considered rarely from an experimental approach. From 1996 to 1998, we experimentally created a gypsy moth outbreak that defoliated large plots of mature hybrid poplars, Populus ×euramericana, with half of the plots fertilized in a factorial design. The trees were harvested at rotation age in 1999,...

In natural environments, plants develop adaptive mechanisms at the cellular and molecular levels to cope with many external factors, e.g., insects soil pathogens. We studied physiological stress induced by different of foliage removal (defoliation 30% 60%) infection root rot pathogen Phytophthora plurivora on common Polish tree species, Betula pendula, grown in an open greenhouse. This study sh...

On the basis of tests with over 20 species of erect plants, we reported in 1962 (9) that a strong growth curvature develops in the axis when an erect plant is rotated slowly on a horizontal clinostat. A differential transport of endogenous auxin was indicated by the production of a similar, predictable curvature after the application of triiodobenzoic acid (TIBA) to 1 side of the immature axial...

Understory shrubs are frequently attacked by insect herbivores. However, very little is known regarding possible interactions between light condition, defoliation (D) and fine root vitality (% live roots) and metabolic activity, and whether different plant strategies (compensation, trade-off and equilibrium) to defoliation depend on individual species light requirements. To explore the response...

The potential of insects to cause temporary spatial shifts of the forest-steppe borderline was investigated in a case study in the northern Mongolian mountain taiga, where Larix sibirica forests border on montane meadow steppe. Insect herbivores of L. sibirica in northern Mongolia include gypsy moth (Lymantria dispar) and grasshoppers, which defoliate trees. Grasshoppers have (like mice) an add...