Freezing behaviours in plant tissues : visualization using NMR micro-imaging and biochemical regulatory factors involved

NMR micro-imaging is a powerful tool to study freezing behaviours in cold-hardy plant tissues since it can non-invasively provide spatially specific information. Cold-hardy plant tissues appear to have developed various mechanisms to control freezing, such as anti-nucleation activity, ice-nucleating activity and antifreeze activity. Studies are underway to isolate compounds and/or genes responsible for these activities and to elucidate their functions in vitro and in vivo. As yet, only a fraction of the whole picture of freeze-regulation mechanisms in plants has been elucidated, including structural mechanisms, which are not covered in the present review