Regeneration of Dioscorea floribunda plants from cryopreserved encapsulated shoot tips: effect of plant growth regulators.
The encapsulation-dehydration protocol for the cryopreservation of in vitro shoot tips of Dioscorea floribunda was optimized. Maximum survival of 87% was obtained when overnight pretreatment with 0.3 M sucrose was followed by encapsulation, preculture in 0.75 M sucrose for 4 d, dehydration in a laminar air flow for 5.5 h, quenching in liquid nitrogen and thawing at 40 degrees C. During recovery growth, 29% shoot formation was obtained when cryopreserved shoot tips were initially cultured for 25 d on a medium with 1.5 mg per liter (-1) BAP, 0.2 mg per liter(-1) NAA and 0.2 mg per liter(-1) GA3 followed by culturing for 15 d on a medium with reduced BAP (1 mg per liter(-1)) but increased NAA (0.5 mg per liter(-1)) and GA3 (0.3 mg per liter(-1)). Finally, transfer on to a medium with further reduced doses of BAP (0.05 mg per liter(-1)) and NAA (0.15 mg per liter(-1)) but without GA3 stimulated production of fully grown plantlets. All plants regenerated without callus formation. Modification of post-thaw culture media with plant growth regulators was essential for regrowth of shoot tips to plantlets.
Mandal
B B
BB
Tissue Culture and Cryopreservation Unit, National Bureau of Plant Genetic Resources, Pusa Campus, New Delhi, India. mandalbinay@yahoo.co.in
Ahuja-Ghosh
Sangeeta
S
D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents; D027742:Dioscorea / Q000187:drug effects* / Q000502:physiology*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018520:Plant Shoots / Q000187:drug effects* / Q000502:physiology*; D013395:Sucrose; D014022:Tissue Survival
D003451:Cryoprotective Agents; D010937:Plant Growth Regulators; D013395:Sucrose