Root growth potential: its development and expression in forest tree seedlings.

Abstract

This review presents a synthesis of current knowledge on Root Growth Potential (RGP) of nursery-grown forest seedlings. RGP, the measure of a transplanted seedling's ability to rapidly produce new roots, is a key indicator of seedling vigour and survival after planting. Physiologically, RGP appears to be closely linked to bud dormancy. It peaks when the chilling requirement for dormancy release is fulfilled, then declines, presumably reflecting the internal allocation of current photo-assimilate to shoot growth. RGP can be manipulated in the nursery through practices that induce dormancy, increase root fibrosity, and enhance carbohydrate reserves. Autumn and winter nursery temperatures influence RGP through their effect on dormancy release. Date of lifting establishes the dormancy status of seedlings when they enter storage, and temperature and duration of storage further influence the dormancy status at the time of planting. Improper handling and misplanting can reduce RGP expression, as can low soil temperature, low soil water potential and soil compaction on the planting site.