title: Melatonin-loaded alginate beads improve cryopreservation of yam (Dioscorea alata and D. cayenensis).
abstract: BACKGROUND
  The cryopreservation of yam is constrained with many challenges.
  
  
  OBJECTIVE
  This study tested the effects of melatonin on shoot tips of D. alata and D. cayenensis accessions exposed to water and liquid nitrogen (LN) stresses.
  
  
  METHODS
  Sucrose pretreatment (0.3 M) was applied for 48 h before cryopreservation. Shoot tips were encapsulated in beads loaded with 0.75 M sucrose, with and without melatonin and desiccated over sterile dry silica gel for 0 - 9 h.
  
  
  RESULTS
  The beads moisture content declined from 100% to ~ 13% after 9 h. The 3 h desiccation period without melatonin produced a significantly higher regeneration compared to 6 h and 9 h. Shoot tips with melatonin had significantly higher regeneration after 3 - 6 h desiccation compared to 9 h and the regeneration of all accessions after 6 h was >80%. Regeneration following 6 h desiccation and LN was significantly greater for melatonin-treated shoot tips compared to non-treated ones.
  
  
  CONCLUSIONS
  The results indicate that melatonin significantly increased regeneration from 15% to 35%.
authors.affiliation: Department of Agronomy, Faculty of Agriculture and Forestry, University of Ibadan, Ibadan, Nigeria ee.uchendu@ui.edu.ng.
authors.forename: E E
authors.initials: EE
authors.lastname: Uchendu
authors.affiliation: Leibniz Institute for Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, D-06466 Stadt Seeland OT Gatersleben, Germany.
authors.forename: E R
authors.initials: ER
authors.lastname: Joachim Keller
mesh_terms: D000464:Alginates / Q000494:pharmacology*; D015925:Cryopreservation / Q000379:methods*; D003890:Desiccation; D027742:Dioscorea / Q000502:physiology*; D020723:Glucuronic Acid / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D008550:Melatonin / Q000494:pharmacology*; D009584:Nitrogen / Q000737:chemistry; D018520:Plant Shoots; D012038:Regeneration; D013045:Species Specificity; D014867:Water / Q000737:chemistry
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D014867:Water; D020723:Glucuronic Acid; D008550:Melatonin; D009584:Nitrogen