Variability in the intraspecific response of Pinus ponderosa seedlings subjected to long-term exposure to elevated CO(sub 2)

摘要

The authors are investigating the effects of elevated CO(sub 2) and intraspecific variability on Pinus ponderosa. To analyze intraspecific variability, they included seedling source (family) as an additional treatment, using a split-plot experimental design. The three elevated CO(sub 2) treatments were ambient (approx. 350 ppm CO(sub 2)), ambient + 175 ppm CO(sub 2) and ambient +350 ppm CO(sub 2). Their study uses the source/sink control framework at several key integrating steps, incorporating the long-term effects of elevated CO(sub 2) (insuring sufficient time for the expression of any long-term physiological and biochemical acclimation to occur) and genetics (using multiple species and multiple known genetic sources) in an attempt to ascertain the extent of overall regulation contributed by selected independent regulatory process at the physiological, biochemical and structural level. In order to assess intraspecific variability, this paper reports on the integration of measurements of photosynthesis, chlorophyll fluorescence, pigmentation, RuBPCase, SPSase to quantify the effects of elevated CO(sub 2) on the growth response of various families of the same species.