Title: Seasonal trends of light-saturated net photosynthesis and stomatal conductance of loblolly pine trees grown in contrasting environments of nutrition, water and carbon dioxide
Author: Murthy, Ramesh; Zarnoch, Stanley J.; Dougherty, P.M.;
Source: Plant, Cell and Environment, Vol. 20: 558-568
Publication Series: Miscellaneous Publication
Description: Repeated measures analysis was used to evaluate the effect of long-term CO2 enhancement on seasonal trends of light-saturated rates of net photosynthesis (Asat) and stomatal conductance to water vapour (gsat) of 9-year-old loblolly pine (Pinus taeda L.; trees grown in a 2x2 factorial experience mental design of nutrition and water. A significant interaction effect of CO2 and nutrition on mean Asat was observed for juvenile foliage. also, juvenile foliage exposed to +350 μmol mol-1 CO2 had a higher rate of increase of Asat between late summer and early autumn. This would lead to a greater potential for recharging carbohydrate reserves for winter. Mature foliage was affected by CO2, water and nutrient treatments in two ways. First, Asat was significantly increased as a result of elevated CO2 in January, a period when stomatal conductance was only 47% of the maximum observed rate. Secondly, the rate of increase of Asat from winter to early spring was accelerated as a result of both nutrient + water and +350 μmol mol-1 CO2 treatments. This accelerated response resulted in a greater potential for photosynthate production during the period when growth initiation occurred. Nutrient, water or carbon dioxide treatments did not significantly alter trends in gsat for mature or juvenile foliage. A significant nutrient X CO2 interaction was observed for the mature foliage, suggesting that gsat increased with increasing CO2 and nutrition. These results may have important consequences for the determination of the water use efficiency of loblolly pine. In spite of low gsat in the winter to early spring period, there was a substantial gain in Asat attributable to elevated CO2 concentrations.
Keywords: Pinus taeda L., elevated CO2, net photosynthesis, repeated measure analysis, stomatal conductance
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication. (Please specify exactly
which publication you are requesting and your mailing address.)
XML: View XML
Murthy, Ramesh; Zarnoch, Stanley J.; Dougherty, P.M. 1997. Seasonal trends of light-saturated net photosynthesis and stomatal conductance of loblolly pine trees grown in contrasting environments of nutrition, water and carbon dioxide. Plant, Cell and Environment, Vol. 20: 558-568
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility