Effects of elevated CO2 and nitrogen on wood structure related to water transport in seedlings of two deciduous broad-leaved tree species

Abstract

Wood structure might be altered through the physiological responses to atmospheric carbon dioxide concentration ([CO 2 ]) and nitrogen (N) deposition. We investigated growth, water relations and wood structure of 1-year-old seedlings of two deciduous broad-leaved tree species, Quercus mongolica (oak, a ring-porous species) and Alnus hirsuta (alder, a diffuse-porous species and N 2 -fixer), grown under a factorial combination of two levels of [CO 2 ] (36 and 72 Pa) and nitrogen supply (N; low and high) for 141 days in phytotron chambers. In oak, there was no significant effect of [CO 2 ] on wood structure, although elevated [CO 2 ] tended to decrease stomatal conductance (g s ) and increased water use efficiency regardless of the N treatment. However, high N supply increased root biomass and induced wider earlywood and larger vessels in the secondary xylem in stems, leading to increased hydraulic conductance. In alder, there was significant interactive effect of [CO 2 ] and N on vessel density, and high N supply increased the mean vessel area. Our results suggest that wood structures related to water transport were not markedly altered, although elevated [CO 2 ] induced changes in physiological parameters such as g s and biomass allocation, and that N fertilization had more pronounced effects on non-N 2 -fixing oak than on N 2 -fixing alder.

Cork oak (Quercus suber L.) seedlings acclimate to elevated CO2 and water stress: photosynthesis, growth, wood anatomy and hydraulic conductivity

“…However, contradictory results have been published on the effect of elevated CO 2 on wood anatomy. For example, in Q. ilex seedlings (Gartner et al 2003;Watanabe et al 2008) elevated CO 2 in the atmosphere promoted an increase in vessel diameter while no obvious effect was found in other diffuse-porous species such as Populus tremuloides (Kaakinen et al 2004) and Betula pendula (Kostiainen et al 2006). Consistent with the wood anatomical traits in Q. suber seedlings, no differences were found in xylem hydraulic efficiency between CO 2 treatments.…”

Elevated CO2 ameliorated oxidative stress induced by elevated O3 in Quercus mongolica

“…In addition, it has been illustrated that ambient level of O 3 in Japan was not high enough to suppress the growth of Q. mongolica (Matsumura 2001), but a mathematical model estimated that its annual net production was negatively affected by ambient O 3 in Korea (Wook and Kim 1997). Elevated CO 2 was reported to decrease stomatal conductance and increase water use efficiency but have no significant effect on wood structure in Q. mongolica (Watanabe et al 2008). To date, the combined effects of elevated O 3 and CO 2 on Q. mongolica have not been reported.…”

Ecophysiology of deciduous trees native to Northeast Asia grown under FACE (Free Air CO₂ Enrichment)

“…Many FACE studies showed that eCO 2 did not stimulate vessel size in the stem of several tree species (e.g., Kostiainen et al, 2008, Watanabe et al, 2010. On the other hand, an application of abundant fertilizer rather than eCO 2 stimulated the size of conduit cells (Yazaki et al, 2001;Watanabe et al, 2008). Why no change was found in the lumen size or number of vessels under eCO 2 ?…”

“…In some species there was an increase in the size of the lumen of conduit cells (e.g., Gartner et al, 2003;Kostiainen et al, 2009;, while in others there was not (e.g., Yazaki et al, 2004;Kostiainen et al, 2008;Watanabe et al, 2008).…”

“…(Tatewaki, 1958). By comparing the effects of CO 2 and acid deposition among three regions (Bazzaz, 1996;Körner et al, 2005;Eguchi et al, 2008a;Watanabe et al, 2008), insight can be gained into future changes in vegetation and production (e.g. Ainsworth and Long, 2005).…”