Wood formation is altered in poplar under ozone and/or elevated carbon dioxide
Résumé
The industrial development led to an increase in the concentration of atmospheric carbon dioxide but also resulted in an increase of tropospheric ozone concentrations. Ozone has been suggested to cause the greatest amount of damage to vegetation as compared to other gaseous pollutants. On the opposite, elevated carbon dioxide is usually observed to enhance tree photosynthesis and growth. We investigated the effects of elevated carbon dioxide and/or ozone on wood formation in young poplars. Trees were bent in order to induce tension wood formation on the upper side of the stem and opposite wood on the lower side. Under ozone, lignin and cellulose biosynthesis decreased probably due to lower availability in carbon skeletons. Cellulose was more affected than lignin resulting in a reduction of cellulose to lignin ratio in wood. Wood anatomy and density was also modified by ozone. Tension wood was generally more altered than opposite wood. All these results showed a strong impact of ozone on wood formation and wood quality and suggested a coordinated regulation of lignin and cellulose synthesis. Elevated carbon dioxide had a low impact on wood formation but the combination with ozone resulted in an attenuation of ozone effects.
Domaines
Sciences agricoles| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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