Changes in osmotic potential during bud break and leaf development of Nothofagus menziesii, Weinmannia racemosa, Quintinia acutifolia, and Ixerba brexioides

Abstract

Osmotic potential (ψ_s) was determined from freezing point depression measurement on leaf exudates. Similar values of ψ_s were found from pressure volume methods. Increased ψ_s before and during budbreak was followed by a recovery towards normal values. This pattern is similar to that usually reported for evergreen trees. ψ_s was generally higher on sites of greater altitude reflecting the wetter environment. The results suggest that the seasonal variation in ψ_s is greater than betweensite differences.