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Insect injury and plant gas exchange processes
Abstract
I characterized the influence of insect injury on plant gas exchange processes in studies from 1992 through 1994 to develop more encompassing explanations of plant response to injury. Studies were conducted to characterize the gas exchange responses of apple and crabapple to simulated and actual leaf-mass consumption by cecropia moth larvae. Photosynthetic rates of injured apple and crabapple leaves were not significantly different from uninjured leaves. Photosynthetic rates of injured crabapple leaves were not significantly different from uninjured leaves 3, 27, or 75 hr after the cessation of injury. Stomatal conductance and transpiration rates were not significantly different among treatments. Therefore, the principal effect of leaf-mass consumption on photosynthetic responses of apple and crabapple was to reduce leaf area, not photosynthetic rates. Studies were conducted to characterize the temporal gas exchange responses of soybean following leaf-mass consumption. Gas exchange parameters of soybean leaflets generally were not significantly affected by gross tissue removal at approximately 0.25, 1, 3, and 24 hr after injury was imposed. The results support previous research which indicates that gross tissue removal does not appreciably alter photosynthetic rates of injured soybean leaves. Studies were conducted to determine the nature and extent of photosynthetic rate reductions after injury by Mexican bean beetle. Both adults and larvae reduced photosynthetic rates of the remaining tissue of the injured leaflet on both soybean and dry bean. A significant linear relationship between photosynthetic rate and percentage injury was observed for both adult and larval injury. Injury reduced photosynthetic rates in all varieties used in the experiments. There was no recovery of photosynthetic rates after injury of an individual leaflet. Stomatal conductance rates were not consistently different between injured and uninjured leaflets. Additionally, intercellular CO$\sb2$ concentrations were similar or higher in injured leaflets. Consequently, reductions in photosynthesis do not seem to be attributable to stomatal limitations. Quantum efficiency was not affected by injury, indicating that light harvesting structures were not perturbed. Results suggest that the limitation must be associated with phosphate utilization.
Subject Area
Ecology|Entomology|Botany
Recommended Citation
Peterson, Robert Keith Dominick, "Insect injury and plant gas exchange processes" (1995). ETD collection for University of Nebraska-Lincoln. AAI9538649.
https://digitalcommons.unl.edu/dissertations/AAI9538649