Performance of loblolly pine (Pinus taeda L.) seedlings and micropropagated plantlets on an east Texas site II. Water relations

Loblolly pine (Pinus taeda L.) seedlings and plantlets, produced from drought resistant genetic families were planted in east Texas and their relative water relations compared through the first two, sixth and seventh growing seasons. Stock type (seedling or plantlet) had a larger influence on water relations than did family source in the early years. Seedlings exhibited more of those characteristics generally considered to benefit survival under harsh environments. The principal difference between stock types was the degree of progressive decrease in predawn water potential (Ψpre) through the growing season. On average and across families, Ψpre decreased through the first growing season by 32 and 17% for plantlets and seedlings, respectively.