Stomatal frequency adjustment of four conifer species to historical changes in atmospheric CO₂

Abstract

The species-specific inverse relation between atmospheric CO(2) concentration and stomatal frequency for many woody angiosperm species is being used increasingly with fossil leaves to reconstruct past atmospheric CO(2) levels. To extend our limited knowledge of the responsiveness of conifer needles to CO(2) fluctuations, the stomatal frequency response of four native North American conifer species (Tsuga heterophylla, Picea glauca, Picea mariana, and Larix laricina) to a range of historical CO(2) mixing ratios (290 to 370 ppmV) was analyzed. Because of the specific mode of leaf development and the subsequent stomatal patterning in conifer needles, the stomatal index of these species was not affected by CO(2). In contrast, a new measure of stomatal frequency, based on the number of stomata per millimeter of needle length, decreased significantly with increasing CO(2). For Tsuga heterophylla, the stomatal frequency response to CO(2) changes in the last century is validated through assessment of the influence of other biological and environmental variables. Because of their sensitive response to CO(2), combined with a high preservation capacity, fossil needles of Tsuga heterophylla, Picea glauca, P. mariana, and Larix laricina have great potential for detecting and quantifying past atmospheric CO(2) fluctuations.

Distribution and Uptake Dynamics of Mercury in Leaves of Common Deciduous Tree Species in Minnesota, U.S.A.

“…45 Stomata on tamarack needles were counted directly without the aid of an impression. 46,47 In the intraseasonal Hg uptake study, we monitored total Hg concentrations in leaves of six deciduous species (Table 1) over the full growing season from emergence to senescence to determine Hg uptake dynamics and to evaluate differences among species. Additionally, we monitored total Hg in the surface, cuticle, and tissues of tamarack needles throughout the 2005 season to investigate the contribution of each compartment to total Hg uptake.…”

Plant Paleoecology in Deep Time1

“…An inverse relationship exists between the pCO 2 and stomatal index (SI; Poole & Kürschner, 1999) such that stomatal indices (the ratio of stomata to epidermal cells) decrease as the concentration of atmospheric CO 2 increases. This inverse response is found in both angiosperms and gymnosperms (e.g., Kouwenberg et al, 2003) but is not limitless. It has been demonstrated in modern angiosperms that not only will different species within the same genus reach their own SI limit at different pCO 2 (e.g., Quercus L.; Kü rschner, 1997), but species of the same genus (Quercus) grown under identical climate and atmospheric gas conditions exhibit statistically significant differences in both stomatal density and SI values (Cantor et al, 2006).…”

The World Flora Online, Target 1 of the Global Strategy for Plant Conservation, and the Species Plantarum Programme: Flora of the World: Compatible Concepts or Mutually Exclusive Mandates?

“…de BaRy) à l'origine de la famine irlandaise a pu être clairement identifié sur le plan génétique grâce à des analyses réalisées sur 28 échantillons d'herbier collectés entre 1845 et 1847 en Irlande (Ristaino et al, 2001 Une diminution de la densité des stomates, consécutive à l'augmentation des teneurs en CO 2, a été mise en évidence au Royaume-Uni sur des échantillons d'herbiers de feuilles d'espèces ligneuses (Woodward 1987 ;Beerling et Chaloner, 1993). Des résultats similaires ont ensuite été obtenus en Amérique du Nord (Kouwenberg et al, 2003), ainsi qu'en forêt tropicale en Australie (Greenwood et al, 2003). Plus récemment, une étude a été menée en Guyane française sur la réponse fonctionnelle de deux espèces ligneuses de la forêt tropicale à partir de l'analyse des isotopes de C et O obtenus sur des échantillons d'herbiers de feuilles collectés sur une période de 200 ans (Bonal et al, 2011).…”