Novel approaches for regulating gas supply to plant systems in vitro: Application and benefits of artificial gas carriers

The composition of the gaseous environment within tissue culture vessels is a critical factor in determining in vitro plant growth and morphogenic responsiveness. Consequently, the provision of an adequate and sustainable oxygen supply for cultured plant cells (including isolated protoplasts), tissues and organs is a crucial prerequisite for optimization and regulation of such cultural responses. During the past decade, research has focused on improving growth and development using artificial gas carriers based on inert perfluorocarbon (PFC) liquids and hemoglobin (Hb) solution. Supplementation of culture media with such artificial oxygen carriers has demonstrated beneficial effects of increased and sustainable cellular mitotic division and subsequent biomass production in a diverse range of plant species, during both short- and longer-term culture. Studies have targeted systems where oxygen availability is actually or potentially a major growth-limiting factor. Undoubtedly, gas carrier-facilitated improvements in regulating the supply of respiratory gases to cultured cells, tissues and organs will have increasingly important biotechnological and practical implications in the context of plant micropropagation, somatic hybridization, transgenic plant production, and secondary product biosynthesis.