Effects of acorn storage duration and parental tree on emergence and physiological status of Cork oak (Quercus suber L.) seedlings

This study was conducted to evaluate how parental trees and seed storage du ration influenced subsequent seedling physiological status and growth. Seed ling emergence rate was higher than 90% independently of the duration of se ed storage or parental trees. Seed storage shortened significantly the time and increased the uniformity of seedling emergence. Consequently, the dela yed seedling emergence from fresh seeds could be explained by epicotyl dorm ancy. Seed size varied with parental tree. Seedling growth rate was greatly affected by seed size, independently of storage treatment. Seedlings origi nating from large seeds (>5 g) had the fastest growth rates and seedlings f rom the smallest seeds (<4 g) had the slowest. Final shoot height, however, depended on the duration of seed storage. The seed size and the duration o f storage had a great effect on the initial rate of leaf production, but di d not affect the final number of leaves. Leaf chlorophyll concentration was reduced as the duration of seed storage increased but was independent of p arental tree (i.e., seed size). Seedling biomass was positively related to seed size. The duration of seed storage reduced the shoot/root ratio, but n o significant effect was observed among parental trees. The shoot/root valu e of seedlings from stored seed was about 1.5 and the one of seedlings from fresh seed was about 2.