Gas exchange and dry matter allocation responses to elevation of atmospheric CO2 concentration in seedlings of three tree species

1 September 1987

journal article
research article
Published by Oxford University Press (OUP) in Tree Physiology

Vol. 3 (3) , 193-202
https://doi.org/10.1093/treephys/3.3.193

Abstract

Photosynthetic rates of 13-month-old Pinus radiata D. Don, Nothofagus fusca (Hook f.) Ørst. and Pseudotsuga menziesii (Mirb.) Franco seedlings grown and measured at elevated atmospheric concentrations of CO₂ (∼620 μl l⁻¹) were 32 to 55% greater than those of seedlings grown and measured at ambient (∼310 μl l⁻¹) concentrations of CO₂. Seedlings grown in ambient and elevated concentrations of CO₂ had similar rates of photosynthesis when measured at ∼620 μl l⁻¹ CO₂, but when measured at ∼310 μl l⁻¹ CO₂, the P. radiata and N. fusca seedlings which were grown at elevated CO₂ had lower rates of photosynthesis than the seedlings grown at an ambient concentration of CO₂. Stomatal conductances in general were lower when measured at ∼620 μl l⁻¹ CO₂ than at ∼310 μl l⁻¹ CO₂. Stomatal conductances declined in all species grown at both CO₂ concentrations when the leaf-air water vapor concentration gradient (ΔW) was increased from 10 to 20 mmol H₂O mol⁻¹ air. The percent enhancement in photosynthesis for P. radiata and P. menziesii at elevated CO₂ was greater at 20 mmol than at 10 mmol ΔW, suggesting that elevated CO₂ may moderate the effects of atmospheric water stress. Dry matter allocation patterns were not significantly different for plants grown in ambient or high CO₂ air.

Keywords

This publication has 0 references indexed in Scilit: