title: Stem and crown growth of Japanese larch and its hybrid F1grown in two soils and exposed to two free-air O3regimes.
abstract: Ozone (O3) pollution and soil infertility may negatively affect boreal forests across the Northern Hemisphere. Impacts to economically and ecologically important larches (Larix sp., Pinacaeae) are particularly concerning. Using a free air O3enrichment (FACE) system, we investigated the effect of 2-year elevated O3exposure (≈66 nmol mol-1) on Japanese larch (L. kaempferi) and its hybrid larch F1(L. gmelinii var. japonica × L. kaempferi) planted directly into either fertile brown forest soil (BF) or BF mixed with infertile volcanic ash soil (VA). Overall, photosynthetic pigmentation and the growth performance of the stem and crown were reduced in both taxa exposed to elevated O3. Furthermore, hybrid larch, in both O3treatments, performed better than Japanese larch. This finding contradicts findings of prior experiments with potential experimental artifacts of O3exposure facilities and root restrictions. Elevated O3also disproportionately inhibited stem diameter growth and caused an imbalance in chlorophylls a/b and chlorophyll/carotenoid ratios. Hybrid and Japanese larches grown in BF and VA had a significantly lower drop of stem diameter over the run of stem height (from base to top) when exposed to elevated O3, compared to ambient O3. This finding indicates altered stem shape under elevated O3. Among 11 response variables, there were no significant interactions between O3treatment and taxa. There was also no significant interaction of soil condition and taxa, suggesting that the two larches shared a similar response to O3and soil type. Understanding the performance of hybrid larch in relation to its parent species has ramifications for breeding success in a soil-degraded and O3-polluted environment.
authors.affiliation: School of Agriculture, Hokkaido University, Sapporo, Hokkaido, 060-8589, Japan. evgenios_ag@hotmail.com.|Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Hitsujigaoka 7, Sapporo, Hokkaido, 062-8516, Japan. evgenios_ag@hotmail.com.
authors.forename: Eugenios
authors.identifier: http://orcid.org/0000-0002-0058-4857
authors.initials: E
authors.lastname: Agathokleous
authors.affiliation: HUSTEP, School of Engineering, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan.|School of Biological Sciences, The University of Sydney, Camperdown, NSW, Australia.
authors.forename: Amelie
authors.initials: A
authors.lastname: Vanderstock
authors.affiliation: Hokkaido Forestry Research Institute, HRO, Bibai, Hokkaido, 079-0198, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Kita
authors.affiliation: School of Agriculture, Hokkaido University, Sapporo, Hokkaido, 060-8589, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Koike
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D002245:Carbon Dioxide / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D065928:Forests; D007564:Japan; D028221:Larix / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010126:Ozone / Q000032:analysis* / Q000633:toxicity; D010788:Photosynthesis / Q000187:drug effects; D000069600:Plant Breeding; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018547:Plant Stems / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D018707:Volcanic Eruptions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D012987:Soil; D002245:Carbon Dioxide; D010126:Ozone
keywords: Abiotic stress; Crown; O3 biomonitoring; Ozone; Stem shape; Trioxygen