Cryopreservation of Dendrobium hybrid seeds and protocorms as affected by phloroglucinol and Supercool X1000

Abstract

This study was conducted to investigate two cryopreservation protocols for Dendrobium Swartz. hybrid 'Dong Yai'. Vitrification was evaluated for cryopreservation of mature seeds, while droplet-vitrification was evaluated for protocorms of the Dendrobium hybrid. The effectiveness of either phloroglucinol or Supercool X1000 (R) as cryoprotectants was evaluated. In vitro germination, protocorm recovery, and seedling development of cryopreserved seeds and protocorms were assessed, respectively. For seed cryopreservation, the use of the PVS2 vitrification solution for 60 min at 0 degrees C containing 1% phloroglucinol resulted in 79% seed germination. For protocorm cryopreservation, pretreatment with sucrose 0.3 M for 24 h followed by exposure to PVS2 solution containing 1% phloroglucinol for 15 min at 0 degrees C resulted in 14% protocorm survival after 75 days, compared to 0-6% survival for controls and other treatments. Seeds were germinated and the seedlings produced showed normal growth and development, with no abnormalities. The addition of 1% Supercool X1000 (R) was not effective as a cryoprotectant for seeds. Phloroglucinol at 1% was effective as a cryoprotectant for Dendrobium hybrid seed cryopreservation using the vitrification method. Phloroglucinol provided limited effectiveness for the cryopreservation of Dendrobium hybrid protocorms using droplet-vitrification, but recovery was enhanced as compared to controls and other treatments. (c) 2012 Elsevier B.V. All rights reserved.