title: [An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].
abstract: OBJECTIVE
  To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses.
  
  
  METHODS
  In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields.
  
  
  RESULTS
  Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C.
  
  
  CONCLUSIONS
  Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.
authors.affiliation: School of Public Health, Xinjiang Medical University, Urumqi 830054.
authors.forename: H
authors.initials: H
authors.lastname: Yao
authors.forename: W
authors.initials: W
authors.lastname: Yan
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: W
authors.initials: W
authors.lastname: Guo
authors.forename: G
authors.initials: G
authors.lastname: Wang
authors.forename: Z
authors.initials: Z
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Feng
authors.forename: K
authors.initials: K
authors.lastname: Liu
authors.forename: D
authors.initials: D
authors.lastname: Jin
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D003252:Construction Materials; D004780:Environment, Controlled; D008027:Light; D008903:Minerals / Q000032:analysis*; D009753:Nutritive Value; D018515:Plant Leaves / Q000737:chemistry; D014675:Vegetables / Q000737:chemistry* / Q000254:growth & development; D014815:Vitamins / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D008903:Minerals; D014815:Vitamins