Tolerance of apexes of coral Pocillopora damicornis L. to cryoprotectant solutions

In this study, we investigated the tolerance of Pocillopora damicornis apexes to treatments with solutions containing penetrating and non-penetrating cryoprotective agents (CPAs). CPAs were employed individually or in binary, tertiary or quaternary solutions. In some experiments apexes were treated successively with two CPA solutions with increasing total concentration. P. damicornis apexes withstood exposure for up to 30 min to solutions containing 0.6-0.8 M sucrose (Suc) or trehalose (Tre). When apexes were treated with binary cryoprotectant solutions containing Suc and ethylene glycol (EG), methanol (Meth), dimethyl sulfoxide (Me2SO) or glycerol (Gly), the CPAs employed in combination with Suc could be ranked in the following order of decreasing tolerance: EG > Meth > Me2SO > Gly. P. damicornis apexes tolerated exposure to complex CPA solutions containing Suc, Me2SO, EG and/or Meth with a total molarity of 2.45 M. In experiments where two successive CPA solutions were employed, apexes withstood treatment with the second, more concentrated solution at 0 °C for up to 10 min. These preliminary results pave the way to the development of a cryopreservation protocol for P. damicornis apexes.