title: Elevated CO2 affects secondary metabolites in Robinia pseudoacacia L. seedlings in Cd- and Pb-contaminated soils.
abstract: Secondary metabolites play important roles in plant interactions with the environment. The co-occurrence of heavy metal contamination of soils and rising atmospheric CO2 has important effects on plant. It is important to explore the ways in which production of plant secondary metabolites is affected by heavy metals under elevated atmospheric CO2. We examined the effects of elevated CO2 on secondary metabolite contents in Robinia pseudoacacia seedlings grown in Cd- and lead (Pb)-contaminated soils. The increase in secondary metabolites was greater under Cd + Pb exposure than under exposure to individual metals regardless of elevated CO2 with the exception of condensed tannins in leaves and total alkaloids in stems. Except for phenolic compounds and condensed tannins, elevated CO2 was associated with increased secondary metabolite contents in leaves and stems of plants exposed to Cd, Pb, and Cd + Pb compared to plants exposed to ambient CO2 + metals. Changes in saponins in leaves and alkaloids in stems were greater than changes in the other secondary metabolites. Significant interactive effects of CO2, Cd, and Pb on secondary metabolites were observed. Saponins in leaves and alkaloids in stems were more sensitive than other secondary metabolites to elevated CO2 + Cd + Pb. Elevated CO2 could modulate plant protection and defense mechanisms in R. pseudoacacia seedlings exposed to heavy metals by altering the production of secondary metabolites. The increased Cd and Pb uptake under elevated CO2 suggested that R. pseudoacacia may be used in the phytoremediation of heavy metal-contaminated soils under global environmental scenarios.
authors.affiliation: School of Environmental Science and Engineering, Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education, Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, Chang'an University, Xi'an 710054, PR China. Electronic address: jiaxianavy@163.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Jia
authors.affiliation: The School of Earth Science and Resources, Chang'an University, Xi'an 710054, PR China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Environmental Science and Engineering, Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education, Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, Chang'an University, Xi'an 710054, PR China.
authors.forename: Tuo
authors.initials: T
authors.lastname: Liu
authors.affiliation: School of Environmental Science and Engineering, Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education, Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, Chang'an University, Xi'an 710054, PR China.
authors.forename: Shuping
authors.initials: S
authors.lastname: Huang
mesh_terms: D000470:Alkaloids / Q000378:metabolism; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000493:pharmacokinetics / Q000633:toxicity*; D002245:Carbon Dioxide / Q000494:pharmacology*; D007854:Lead / Q000493:pharmacokinetics / Q000633:toxicity*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018547:Plant Stems / Q000187:drug effects / Q000378:metabolism; D031301:Robinia / Q000187:drug effects* / Q000378:metabolism; D012503:Saponins / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012989:Soil Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*; D013634:Tannins / Q000378:metabolism
chemical_list: D000470:Alkaloids; D012503:Saponins; D012989:Soil Pollutants; D013634:Tannins; D002104:Cadmium; D002245:Carbon Dioxide; D007854:Lead
keywords: Cd- and Pb-contaminated soils; Elevated atmospheric CO(2); Robinia pseudoacacia L. seedlings; Secondary metabolites