In vitro Shoot Tip Response to Encapsulation-Dehydration Procedure for Cryopreservation of Philippine Taro [Colocasia esculenta (L.) Schott]
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- Germplasm Conservation, Cryostorage, Cryoprotectant, Cryopreservation Failure
- Acedo, V. Z.; Damasco, O. P.; Laurena, A. C.; Cruz, P. C. Sta; Namuco, L. O.; Lalusin, A. G.
- This study was conducted to explore the feasibility of the encapsulation-dehydration cryopreservation procedure and provide the groundwork for establishing a cryopreservation protocol for routine application in germplasm conservation of Philippine taro. Shoot tips (2-3 mm) from 2-3 week old in vitro plantlets of VG-2 taro variety cultured on modified Murashige and Skoog (MS) medium were used. Initial experiments determined the effects of pretreatment (liquid MS with 0.15M or 0.3M sucrose), encapsulation (3% sodium alginate in MS solution and 0.1M calcium chloride in MS or distilled water), preculture (24h on MS with 0-1.2M sucrose) and dehydration with silica gel (3h or 4h) on tissue viability to ensure viable tissues before liquid nitrogen (LN) immersion. Results showed that only the high-sucrose preculture affected tissue viability in terms of reduced number of shoot-forming explants and delay in shoot initiation. In the encapsulation-dehydration experiments, the same pretreatment and encapsulation treatments as above, 12-24h preculture in MS with 0-1.0M sucrose, dehydration in silica gel for 3.5h (about 20% moisture content), 1-2d LN immersion, thawing in 40oC water bath for 3 min, and regrowth in MS+5% sucrose or MS+3% sucrose+0.2 mg/L kinetin+0.2 mg/L benzyladenine, were tested. These treatments had no remarkable effect on post-thaw tissue survival. More than 80% of the shoot tips remained green after thawing. After 3d in the regrowth medium, 28-33% of the shoot tips remained green but there was no sign of shoot growth. Lack of regrowth indicates cryopreservation failure and this defines future research toward developing a successful protocol
Full text: IJRAS_668_FINAL.pdf