Effect of lifting date on physiological condition of Taurus cedar (Cedrus libani A. Rich) seedlings

In forest nursery, the optimal lifting period can be change according to species, origin and growing techniques. Determining the optimal lifting period by the use of morphological characteristics may cause irreparable errors. Thus, it is also necessary to determine the physiological conditions of the seedling to accurately identify lifting period. In this study, effects of lifting date on physiological condition of the seedling were examined in order to determine the optimal lifting period in 2+0 aged Taurus cedar (Cedrus libani A. Rich) seedlings grown from two different provenances. Seedlings from Kap？da？ and Bucak provenances were lifted at 7 different dates from January to May in 2016. In each measurement time, water relations parameters by the pressure – volume (P-V) curve technique were estimated, including osmotic potential at full turgor (ψπ100), osmotic potential at turgor loss point (ψπTLP), free water content at turgor loss point (FWCTLP), relative water content at turgor loss point (RWCTLP), relative water content (RWC), symplastic water at saturated point per dry weight of the shoot (V0/DW), apoplastic water fraction (Va/VT) and dry weight fraction (DWF). In addition, root growth potential and total carbohydrate content in root and needle samples were determined. According to the results of this study, ψπTLP, ψπ100, total carbohydrate content in needle and roots, and root growth potential showed a seasonal change. In both provenances, ψπTLP and ψπ100 increased from late January to late February, then decreased early March and increased again to May. No significant differences were determined between measurement dates in FWCTLP and RWC. Total carbohydrate content in root and needles decreased gradually from late January to early May in both provenances. The root growth potential reached the maximum value on late February to Kap？da？ provenance and on early March to Bucak provenance and then fall. Seedlings lifted from January to early March had greater stress resistance than seedlings lifted in the late March, April or May. In E？irdir forest nursery, although the safe period for lifting season are late January to early March, if weather conditions are adverse for lifting or planting, lifting period might be delayed until late March