Báo cáo khoa học: Evaluation of some markers of vigor in seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco)

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Báo cáo khoa học: "Evaluation of some markers of vigor in seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco)Evaluation of some markers of vigor in seedlingsof Douglas fir (Pseudotsuga menziesii (Mirb.) Franco)J.B. Zaerr V.D. Hipkins K. ForryDepartment of Forest Science, Oregon State University, Corvallis, OR 97331,U.S.A. dates throughout the planting season and di-Introduction vided into lots of 70 seedlings for each treat- ment. The following treatments were applied: timely identification of damaged seed-The drying seedlings with exposed roots in a warm,lings or seedlings of low vigor is an impor- dry room (30°C, 30% relative humidity) for 0.25,tant aspect of forest regeneration in the 0.5 or 1 h; freezing to -9, -12 or -15°C; and storage at 2°(; for 0, 2 or 4 mo. There was aPacific Northwestern United States. When total of 30 treatments. Survival in the field plantation fails because seedlings die,a indicated that a wide range of survival percent-replanting is necessary. If damaged or ages was achieved and that there were fairlyseedlings of low vigor could be identified well distributed intermediate values.before they are planted, considerable For each treatment, 20 seedlings were pottedlabor savings could be realized as well as in soil and placed in a greenhouse for measure-improved productivity of the forest (Cleary ment of RGC (number and length of new rootset al., 1982). A practical test of seedling after 30 d), 20 were potted in soil and placed invigor must be easy to conduct and should a growth chamber (21 °C, 16 h photoperiod) to measure survival and bud-burst, 20 wereprovide results quickly. At the present outplanted at a field site near Corvallis (30 x 30time, the root growth capacity (RGC) test cm spacing), and 10 were used for samples ofis used extensively, but results require 2-4 plant material. Xylem sap was extracted with awk and do not always predict field survival pressure chamber apparatus and the osmoticaccurately. The objective of this study was concentration of the sap was measured with an osmometer immediately. The roots were ex-to evaluate 3 recently suggested alterna- cised, steamed for 5-10 min to inactivate thetive indicators of seedling vigor: the starch native enzymes, frozen with liquid nitrogen, lyo-content of roots (Puttonen, 1986), the philized and stored at -80°C until analyzed forosmotic concentration of xylem sap and (n . Starch was analyzed by the starch )= 1 0biochemical markers of seedling vigor amylase/amyloglucosidase method of Haissig and Dickson !1982). The apical 2 cm of the(Duryea, 1985). shoot were excised, ground with methanol in a polytron, extracted 5 times with hexane to remove chlorophyll, dried and stored at -80°CMaterials and Methods until analyzed by high performance liquid chro- matography (FIPLC). For analysis by HPLC, theTwo yr old seedlings of Douglas fir (Pseudo- dried sample was taken up in 1 ml of methanoltsuga menziesii (Mirb.) Franco) were lifted on 4 and a 25 pl sample was injected into a Varian related to survival. Comparable resultsmodel 5000 HPLC fitted with B C, a reversephase column (Spherical ODS, 0.46 x 2 cm, obtained using either the presence were5 ;um), and a Beckman 164 variable wavelength or the area of peaks. Fig. ...