Effects of long‐term atmospheric CO₂ enrichment on the mineral concentration of Citrus aurantium leaves

Abstract

SUMMARYLeaf mineral concentration of Citrus aurantium (sour orange tree) was measured at bi-monthly intervals from 30 to 85 months of exposure in a long-term study on the effects of a 300 [imol mor^ enrichment of atmospheric COg, under conditions of high nutrient and water supply. There were clear seasonal trends in the concentrations of most of the elements studied. There were initial decreases in the leaf concentrations of N and the xylem-mobile, phloem-immobile elements Mn, Ca and Mg, as well as a significant and sustained increase in the leaf concentration of B, and no changes in the concentrations of K, Fe, Na, P, S, Zn and Cu. Interestingly, the initial reductions in the leaf concentrations of Mn, N, Ca and Mg gradually disappeared with time.

Effects of elevated atmospheric CO2 and tropospheric O3 on nutrient dynamics: decomposition of leaf litter in trembling aspen and paper birch communities

“…This has been attributed to either decreased nutrient uptake relative to C accumulation, or altered patterns of nutrient allocation under elevated CO 2 (Penuelas et al 1997). However, published data for several species show no consistent response of foliar nutrient concentrations to elevated CO 2 ( Table 1).…”

“…The objective of this study was to investigate the independent and combined effects of elevated CO 2 and Pfirrmann et al (1996) b Penuelas et al (2001) c Penuelas et al (1997) d Huluka et al (1994) e Heagle et al (1993) elevated O 3 on mineral nutrient cycling in aggrading aspen and birch-aspen stands of the Aspen FACE project in Rhinelander, WI. Elevated CO 2 increased total biomass production by 43% and elevated O 3 decreased it by 17% in this long-term experiment (King et al 2005b).…”

Elevated CO2 affects plant responses to variation in boron availability

“…Decreases in [B] with growth under elevated CO 2 have also been observed in most (Peñuelas et al 2001;Norby et al 1986;O'Neill et al 1987;Liu et al 2007), but not all (Peñuelas et al 1997;Luomala et al 2005), previous studies wherein B was measured. Decreases in the uptake rate of B at high CO 2 in this study were unrelated to the presence or absence of high-CO 2 -stimulation of growth, and so are unlikely to be linked to total plant demand for B.…”

“…Notably, we can find only six previous studies wherein effects of elevated CO 2 on tissue B concentrations were investigated (Table 1; Norby et al 1986;O'Neill et al 1987;Peñuelas et al 1997Peñuelas et al , 2001Luomala et al 2005;Liu et al 2007). As chance would have it, each of these studies (four reports on trees and two on shrubs) examined CO 2 -responses in plants grown in soil characterized by the authors as "nutrient poor" or "low in N", and B soil availability was undetermined and un-manipulated in these studies.…”

“…Consistent with these expectations, several past studies have reported that high-CO 2 -stimulation of plants under nutrient-deficient conditions is less, or even absent, when compared to nutrient-sufficient conditions (Cure et al 1988;Coleman et al 1993;Ziska 2003). Because elevated CO 2 is expected to alter plant tissue nutrient concentrations, many studies have examined effects of elevated CO 2 on nutrient relations, but most previous studies have focused on macro-nutrients, especially N, (e.g., Ehleringer et al 2002;Ellsworth et al 2004;Sicher 2005;Tang et al 2006;Taub and Wang 2008 and references therein), and only a few have examined CO 2 effects on micro-nutrient relations (Norby et al 1986;O'Neill et al 1987;Manderscheid et al 1995;Fangmeier et al 1997;Peñuelas et al 1997Peñuelas et al , 2001Prior et al 1998;Blank and Derner 2004;Pal et al 2004;Luomala et al 2005;Jin et al 2009). …”