Science Inventory

EFFECTS OF OPEN-TOP CHAMBERS ON 'VALENCIA' ORANGE TREES

Citation:

Olszyk, D., B. Takemoto, G. Kats, P. Dawson, C. Morrison, J. Preston, AND C. Thompson. EFFECTS OF OPEN-TOP CHAMBERS ON 'VALENCIA' ORANGE TREES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/170 (NTIS PB92180355), 1992.

Description:

Young 'Valencia' orange trees (Citrus sinensis(L) Osbeck) were grown for four years in large open-top chambers with ambient (nonfiltered) air or in outside air to determine any effects of the chambers on the air pollutant susceptibility of the trees. ong-term ozone average concentrations (12 hours, growing season) were 8% lower, and cumulative ozone dose (hourly vales >0.1 L L-1) was 29% lower in ambient chambers compared to outside air. ruit yields were much higher (>39%) for ambient chamber trees than for outside trees over three harvests, due at least partly to less fruit drop during the growing season for ambient chamber trees. mbient chamber trees were much larger than outside trees and produced over twice as much leaf material over four years of study. eaves on ambient chamber trees were larger and less dense than on outside trees. eaves on ambient chamber trees were under more stress than leaves on outside trees during summer months; with lower stomatal conductances (14% average) and transpiration rates (12%), and more negative leaf water pressure potentials (28%). n contrast, leaves on ambient chamber trees had higher net photosynthetic rates (13%) and higher leaf starch concentrations prior to tree flowering (31%), than leaves on outside trees. hile these results indicated large long-term impacts on tree growth which must be considered when using open-top chambers, they did not indicate any net effect of chambers on the air pollutant susceptibility of trees which would limit the usefulness of chamber tree data for air quality impact assessment purposes.

Record Details:

Record Type:DOCUMENT( REPORT )
Product Published Date:12/31/1992
Record Last Revised:12/22/2005
Record ID: 33082