title: [Effect of potassium level on output and diosgenin content of Dioscorea zingiberensisg].
abstract: OBJECTIVE
  To study the effect of potassium level on physiological characteristics and diosgenin content of Dioscorea zingiberensisg and provide experimental basis for proper use of potassium fertilizer.
  
  
  METHODS
  Field experiment including four potassium levels was carried out. The physiological characteristics of leaves were determined at different growth stages and the diosgenin content in bulk root was assayed after harvest.
  
  
  RESULTS
  Within the arrange of 0-180 kg K2SO4/hm2, the content of chlorophyll and amino acid, Fv/Fo, Fv/Fm, and phiPs II were increased with the increase in potassium level. Meanwhile, the ability to defense the damage caused by active oxygen was obviously enhanced. Further increase in potassium level resulted in the decrease in efficiency of potassium fertilizer.
  
  
  CONCLUSIONS
  It indicats that higher yield and diosgenin content can be obtained when the potassium level is 180 kg K2/hm2.
authors.affiliation: Henan Agricultural University, Zhengzhou 450002, China. zhj303@sohu.com
authors.forename: Hui-jie
authors.initials: HJ
authors.lastname: Zhao
authors.forename: Hong-mei
authors.initials: HM
authors.lastname: Gao
authors.forename: Wen-ying
authors.initials: WY
authors.lastname: Guo
authors.forename: Hui-ling
authors.initials: HL
authors.lastname: Xie
authors.forename: Li-fei
authors.initials: LF
authors.lastname: Zhao
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D027742:Dioscorea / Q000737:chemistry* / Q000254:growth & development* / Q000378:metabolism; D004144:Diosgenin / Q000032:analysis* / Q000302:isolation & purification; D005308:Fertilizers; D009584:Nitrogen; D010710:Phosphates; D010788:Photosynthesis; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D010946:Plants, Medicinal / Q000737:chemistry / Q000254:growth & development*; D011188:Potassium / Q000008:administration & dosage; D027343:Rhizome / Q000737:chemistry / Q000254:growth & development; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D000596:Amino Acids; D005308:Fertilizers; D010710:Phosphates; D002734:Chlorophyll; D013482:Superoxide Dismutase; D004144:Diosgenin; D009584:Nitrogen; D011188:Potassium