title: Impact of elevated O3 on visible foliar symptom, growth and biomass of Cinnamomum camphora seedlings under different nitrogen loads.
abstract: The effects of elevated ozone (O(3)) and enhanced nitrogen (N) on the growth and biomass of Cinnamomum camphora, a subtropical evergreen broad-leaved tree species, were investigated. The seedlings, supplied with N (NH(4)NO(3) solution) at 0, 30 and 60 kg ha(-1) year(-1) (simplified as N0, N30, N60, respectively), were exposed to ambient (AA) or elevated O(3) (AA + 60 nmol mol(-1) and AA + 120 nmol mol(-1), designated as AA + 60 and AA + 120, respectively) for the 2009 and 2010 growing seasons. Symptomatic leaf percentages were significantly increased with O(3) concentration. AA + 120 significantly decreased the mean leaf size and chlorophyll content of both 2009- and 2010-emerged leaves, inhibited the growth of stem height and basal diameter, and reduced biomass accumulation of all plant parts except for leaves. By comparison, only the chlorophyll content of 2009-emerged leaves and root dry weight were significantly reduced under AA + 60. Specific leaf area, total leaf area and foliar biomass were not affected even at a higher O(3) level. On the other hand, N loads, especially N60, exerted significantly positive effects on all variables except mean leaf size and shoot/root ratio. No significant interactions between O(3) and N were detected, suggesting that the N supply at ≤60 kg ha(-1) year(-1) did not significantly modify the response of C. camphora to O(3) in terms of seedling growth and biomass accumulation.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 2871 mailbox, Shuangqing Road 18, Haidian District, Beijing, 100085, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Niu
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhaozhong
authors.initials: Z
authors.lastname: Feng
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D000397:Air Pollution / Q000706:statistics & numerical data; D002734:Chlorophyll / Q000378:metabolism; D027423:Cinnamomum camphora / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D004784:Environmental Monitoring; D009584:Nitrogen / Q000032:analysis* / Q000378:metabolism; D010126:Ozone / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D002734:Chlorophyll; D010126:Ozone; D009584:Nitrogen