Effects of elevated CO₂ on leaf photosynthetic rate (Pn) to leaf respiration rate (R) ratio (Pn/R) at different temperatures at 7 d (a), 14 d (b), 21 d (c), and 28 d (d) of temperature treatment, and the dotted line represents Pn/R ratio was 1.0.

Abstract

<p>Vertical bars represent the values of least significant difference at p = 0.05 for comparison of CO₂ treatment effects at a given temperature.</p