Pluronic F-68 increases the post-thaw growth of cryopreserved plant cells

The beneficial effects of supplementing culture media with Pluronic F-68 (0.01-0.2% w/v), on post thaw growth following cryopreservation of suspension-cultured cells of Oryza sativa cvs. Taipei 309 and Tarom (Japonica rices), together with Lolium multiflorum um (Italian ryegrass), were studied. The mean absorbance, following triphenyltetrazolium chloride (TTC) reduction, of Taipei 309 cells 4 days after thawing was increased twofold over control by 0.01% (w/v) Pluronic F-68 (P < 0.01) and almost twofold by 0.1% (w/v) surfactant. A more pronounced, fourfold increase (P < 0.001) in post-thaw absorbance occurred with Tarom cells exposed to 0.1% (w/v) Pluronic F-68; cell absorbance was elevated threefold with 0.2% (w/v) Pluronic (P < 0.001) and twofold (P < 0.001) by 0.01% (w/v) surfactant. TTC reduction by Lolium cells was elevated 31% (P < 0.01) with 0.01% (w/v) surfactant. Pluronic F-68 (0.01% w/v) also promoted sustained mitotic activity since biomass, measured 30 days post-thawing. was increased to a maximum of 32% above control (P < 0.05), in both Taipei 309 and Lolium. There was no measurable beneficial effect of adding Pluronic F-68 to the cryoprotectant before freezing. These results, which demonstrate a marked cytoprotection of Pluronic F-68 on plant cells recovered from cryostorage, suggest that this surfactant is a useful additive agent in post-thaw handling strategies. (C) 1996 Academic Press, Inc.