Section 81
Chapter 80,069

Elevated ozone inhibits isoprene emission of a diploid and a triploid genotype of Populus tomentosa by different mechanisms

Li, S.; Feng, Z.; Yuan, X.; Wang, M.; Agathokleous, E.

Journal of Experimental Botany 73(18): 6449-6462


ISSN/ISBN: 1460-2431
PMID: 35767843
Accession: 080068779

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Ozone (O3) pollution affects plant growth and isoprene (ISO) emission. However, the response mechanism of isoprene emission rate (ISOrate) to elevated O3 (EO3) remains poorly understood. ISOrate was investigated in two genotypes (diploid and triploid) of Chinese white poplar (Populus tomentosa Carr.) exposed to EO3 in an open top chamber (OTC) system. The triploid genotype had higher photosynthesis rate (A) and stomatal conductance (gs) than the diploid one. EO3 significantly decreased A, gs, and ISOrate of middle and lower leaf positions in both genotypes. In the diploid genotype, the reduction of ISOrate was caused by a systematic decrease related to ISO synthesis capacity, as indicated by decreased contents of isoprene precursor dimethylallyl diphosphate (DMADP) and isoprene synthase (ISPS) protein and activity of ISPS. On the other hand, the negative effect of O3 on ISOrate of the triploid genotype did not result from inhibited ISO synthesis capacity, but from increased ISO oxidative loss within the leaf. Our findings will be useful for breeding poplar genotypes with high-yield and lower ISOrate, depending on local atmospheric VOC/NOx ratio, to cope with both the rising O3 concentrations and increasing biomass demand. They can also enlighten the incorporation of O3 effects into process-based models of isoprene emission.

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