Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Evaluation of some markers of vigor in seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco). | 246s Ann. Sci. For. 1989 46 suppl. 246s-249s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Evaluation of some markers of vigor in seedlings of Douglas fir Pseudotsuga menziesii Mirb. Franco . Zaerr . Hipkins and K. Forry Department of Forest Science Oregon state University Corvallis OP 97331 . Introduction The timely identification of damaged seedlings or seedlings of low vigor is an important aspect of forest regeneration in the Pacific Northwestern United States. When a plantation fails because seedlings die replanting is necessary. If damaged or seedlings of low vigor could be identified before they are planted considerable labor savings could be realized as well as improved productivity of the forest Cleary et al. 1982 . A practical test of seedling vigor must be easy to conduct and should provide results quickly. At the present time the root growth capacity RGC test is used extensively but results require 2-4 wk and do not always predict field survival accurately. The objective of this study was to evaluate 3 recently suggested alternative indicators of seedling vigor the starch content of roots Puttonen 1986 the osmotic concentration of xylem sap and biochemical markers of seedling vigor Duryea 1985 . Materials and Methods Two yr old seedlings of Douglas fir Pseudo-tsuga menziesii Mirb. Franco were lifted on 4 dates throughout the planting season and divided into lots of 70 seedlings for each treatment. The following treatments were applied drying seedlings with exposed roots in a warm dry room 30 C 30 relative humidity for or 1 h freezing to -9 -12 or -15 C and storage at 2 c for 0 2 or 4 mo. There was a total of 30 treatments. Survival in the field indicated that a wide range of survival percentages was achieved and that there were fairly well distributed intermediate values. For each treatment 20 seedlings were potted in soil and placed in a greenhouse for measurement of RGC number and length of new roots after 30 d 20 were
