Effects of carbon dioxides and/or relative humidity on the growth and the transpiration of several plants.
In order to estimate the effects of "global warming" on plants, the effects of carbon dioxide concentration (500 ppm or 1000 ppm CO2) and/or relative humidity (37% or 79% RH) on the growth and the transpiration of several C3 plants and a C4 plant (corn) were investigated by using artificially-lighted growth cabinets. The dry weight growths of all species, especially C3 plants, were accelerated by an elevated concentration of CO2, but were reduced, especially tomato and eggplant, by lowering RH. The leaf area growths of tomato and eggplant were accelerated by a high CO2, while those of all species were reduced by a low RH. A high CO2 increased net assimilation rates (NARs) more than relative growth rates (RGRs) of all species. It decreased leaf area ratio (LAR) due to a decrease in specific leaf area (SLA). A low RH decreased RGRs of all plants. while it affected NARs or LARs of some species. The partitioning of dry matter was insignificantly affected by CO2 or RH. Effects of CO2 on the transpiration rate were not observed clearly with C3 species, though a high CO2 decreased the transpiration of corn obviously. A low RH increased the transpiration rates of all species. From these results, the water use efficiencies of many plants, especially corn were kept at a high level by a high CO2 with a high RH condition. The interactive effects between CO2 and RH on the growth and the transpiration were insignificantly observed in these plants.
Shimizu
H
H
National Institute for Environmental Studies, Tsukuba, Japan.
Fujinuma
Y
Y
Omasa
K
K
D018533:Biomass; D002245:Carbon Dioxide / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004780:Environment, Controlled; D017752:Greenhouse Effect; D006813:Humidity; D018526:Plant Transpiration / Q000187:drug effects*; D014675:Vegetables / Q000187:drug effects* / Q000254:growth & development
D002245:Carbon Dioxide