title: Effect of dimethyl phthalate (DMP) on germination, antioxidant system, and chloroplast ultrastructure in Cucumis sativus L.
abstract: Pollution of agricultural soils caused by widely employed plastic products, such as phthalic acid esters (PAEs), are becoming widespread in China, and they have become a threat to human health and the environment. However, little information is available on the influence of PAEs on vegetable crops. In this study, effects of different dimethyl phthalate (DMP) treatments (0, 30, 50, 100, and 200 mg L(-1)) on seed germination and growth of cucumber seedlings were investigated. Although germination rate showed no significant difference compared to control, seed germination time was significantly delayed at DMP greater than 50 mg L(-1). Concentrations of DMP greater than 30 mg L(-1) reduced cucumber lateral root length and number. The measurement of five physiological indexes in cucumber leaves with increasing DMP concentration revealed a decrease in leaf chlorophyll content, while proline and H2O2 contents increased. Peroxidase (POD) and catalase (CAT) activities increased in cucumber plants under 30 and 50 mg L(-1) DMP treatments compared to control; while after a 7-day treatment, these activities were seriously reduced under 100 and 200 mg L(-1) DMP treatments. According to transmission electron microscopy (TEM) micrographic images, the control and 30 mg L(-1) DMP treatments caused no change to leaf chloroplast shape with well-structured thylakoid membrane and parallel pattern of lamellae. At concentrations higher than 30 mg L(-1), DMP altered the ultrastructure of chloroplast, damaged membrane structure, disordered the lamellae, and increased the number and volume of starch grains. Moreover, the envelope of starch grains began to degrade under 200 mg L(-1) DMP treatment.
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China. zhangyinghr@hotmail.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Na
authors.initials: N
authors.lastname: Du
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tao
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Sun
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Kehinde O
authors.initials: KO
authors.lastname: Erinle
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Pengjie
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Changjian
authors.initials: C
authors.lastname: Zhou
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Duan
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002681:China; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D018553:Cucumis sativus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D018525:Germination / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010795:Phthalic Acids / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D012989:Soil Pollutants / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D010795:Phthalic Acids; D010940:Plant Proteins; D012989:Soil Pollutants; C024629:dimethyl phthalate; D002734:Chlorophyll; D006861:Hydrogen Peroxide; D010544:Peroxidases
keywords: Antioxidant enzyme; Chloroplast ultrastructure; Cucumber; DMP; Root growth; Seed germination