Leaf-level productivity traits in Populus grown in short rotation coppice for biomass energy
2004
Bunn, S.M. | Rae, A.M. | Herbert, C.S. | Taylor, G.
Populus is a genus of extremely fast-growing trees originating in the northern hemisphere, with potential as a source of renewable, biomass energy. The aim of this work was to physiologically characterize genotypes of hybrid poplar, informing future selection, breeding and the development of process-based yield models. Two experiments - a short rotation coppice field trial at two contrasting UK sites and a glasshouse experiment - were conducted on five different genotypes of Populus. The field trial experiment showed that stemwood yields varied between 5.8 and 11.8 t ha-1 a-1 and that the genotype, Hoogvorst (Populus trichocarpa x P. deltoides) was the most productive. This production was characterized at a physiological level by rapid rates of leaf expansion and slow rates of leaf production and, at a cellular level, by the largest epidermal cell number per leaf. The glasshouse experiment confirmed the superior productivity of Hoogvorst, with this genotype producing the largest individual leaf areas (P< = 0.005) that were highly correlated with biomass production (R2 = 0.7). There was no correlation between leaf-level photosynthesis measurements and total biomass production. In general, leaf level photosynthetic characteristics were less able to differentiate between the most productive and less productive genotypes than morphological traits.
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