title: Ammonium nitrate in the culture medium influences regeneration potential of cryopreserved shoot tips of Holostemma annulare.
abstract: Influence of NH4NO3 in the pre-freeze and post-freeze culture medium and 2 or 30 day preconditioning in the presence of 0.5 M sucrose on regeneration of shoot tips of Holostemma annulare following cryopreservation using an encapsulation-dehydration protocol was studied. A long preconditioning phase of 30 days significantly reduced tissue water and improved post-freeze recovery of shoot tips. Under the long preconditioning treatment, Murashige & Skoog (MS) medium free of NH4NO3 (MS-3) allowed maximum regeneration (59%) of liquid nitrogen (LN) exposed shoot tips with less frequency of callusing (10.4%) after 45 days of post-freeze culture. Corresponding desiccated control shoot tips showed 85-90% regeneration. A 3.75 mM NH4NO3 concentration (MS-4) favoured 72-89% and 43-47% regeneration after desiccation and LN exposure respectively. The standard MS medium with 20.6 mM NH4NO3 (MS-1) allowed poor regeneration after desiccation (39-53%) as well as LN exposure (8-23%). The study reveals the importance of reducing ammonium nitrate in the culture medium to get maximum recovery of cryopreserved shoot tips of Holostemma annulare.
authors.affiliation: Plant Biotechnology Division, Tropical Botanic Garden & Research Institute, Palode, Thiruvananthapuram-695562, Kerala, India.
authors.forename: S William
authors.initials: SW
authors.lastname: Decruse
authors.forename: S
authors.initials: S
authors.lastname: Seeni
mesh_terms: D029062:Apocynaceae / Q000502:physiology*; D020148:Butyric Acid / Q000494:pharmacology; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D003470:Culture Media / Q000494:pharmacology*; D003890:Desiccation; D066298:In Vitro Techniques; D009566:Nitrates / Q000494:pharmacology*; D018520:Plant Shoots / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D012038:Regeneration / Q000187:drug effects*; D014867:Water / Q000032:analysis
chemical_list: D003451:Cryoprotective Agents; D003470:Culture Media; D009566:Nitrates; D014867:Water; D020148:Butyric Acid; C006568:ammonium nitrate