Response of 25-day old Eucalyptus globulus to elevated CO2

Increasing [CO2] may influence commercial crop and timber yield. While selection of genotypes sensitive to elevated [CO2] (e[CO2]) appears possible in agricultural crops, there is limited evidence for genotype-by-CO2 (G×CO2) interactions in commercial tree species. We examined [CO2] responsiveness in 124 open-pollinated Eucalyptus globulus subspecies globulus (E. globulus) families with the aim of assessing whether G×CO2 interactions are detectable in seedlings for early-age screening. Plants were grown in ambient (a[CO2]; ~405 μmol mol-1) and e[CO2] (640 μmol mol-1) and harvested 25 days after germination. Total, shoot and root dry weights were determined for each plant. Carbon isotopic discrimination against 13C (Δ13C) was determined at the family level. We observed highly significant (p&lt;0.0001) increases in mean total, shoot, and root dry weights. Mixed-model equations were used to estimate the main and interaction effects of the G×CO2 for each mass trait. The main effects from th...大气二氧化碳浓度（[CO₂]）升高可能对商用作物与用材林木的产量造成影响。尽管在农作物中筛选对高二氧化碳浓度（elevated [CO₂], e[CO₂]）敏感的基因型具备可行性，但目前针对商用树种的基因型-二氧化碳互作（genotype-by-CO₂, G×CO₂）的相关研究证据仍较为匮乏。 本研究以124个开放授粉的蓝桉（Eucalyptus globulus）原亚种（简称E. globulus）家系为材料，检测其对二氧化碳浓度的响应特性，旨在评估是否可在幼苗阶段通过早期筛选检测到G×CO₂互作。 试验设置环境二氧化碳浓度组（a[CO₂]，约405 μmol mol⁻¹）与高二氧化碳浓度组（e[CO₂]，640 μmol mol⁻¹），待种子萌发25天后收获所有植株。测定每株植株的总干重、地上部干重与根系干重，并在家系水平测定其针对¹³C的碳同位素分馏（Δ¹³C）。 结果显示，植株的总干重、地上部干重与根系干重的均值均呈现极显著升高（p<0.0001）。本研究采用混合模型方程，估算各生物量性状的G×CO₂主效应与互作效应。相关主效应源自……