Storage duration and temperature effect on the functional integrity of container and bare-root Pinus radiata D. Don stock-types

We have investigated the effect of storage conditions (duration: 1, 8 or 15 days; temperature: 4 degreesC or 10 degreesC) and root coverage [bare root (BR) or soil-plugged root (PR)] on the water status, electrolyte leakage a nd root growth potential (number of new roots and new root length) of radia ta pine (Pinus radiata D. Don) seedlings. We have also examined the effects that storage causes on plant quality and initial survival potential and th eir usefulness for detecting physiological damage to seedlings. We observed a gradual decrease of seedling water status and an increase in electrolyte leakage, both in root and shoot, with duration of storage, the latter indi cating damage to membranes. Both storage temperature and duration influence d the ability of radiata pine seedlings to initiate and elongate new roots. The effect was mon pronounced in BR than in container seedlings, suggestin g that the rooting-plug medium provides protection against desiccation. The close relationship (r=0.923, P<0.05) between root growth potential and pre dawn xylem water potential before transplanting shows that water potential at the time of transplanting is a reliable predictor of the ability to gene rate new roots. Finally, we have observed a close relationship between surv ival and parameters such as electrolyte conductivity, post-storage water po tential, new root length and root growth potential.