The starch content of roots and the osmotic concentration of expressed xylem sap as predictors of Douglas-fir seelding quality

摘要: approved: Joe B. Zaerr The goal of this study was to evaluate the ability two seedling quality evaluation methods predict field survival Douglas-fir (Pseudotsuga menziesii) seedlings. starch reserves in seedlings have been suggested as a possible predictor quality. Starch shown decrease during cold storage, but there has no concentrated their relationship and survival. This investigated correlation between roots (and needles) subsequent It also evaluated measurements osmotic concentration expressed xylem sap detect damage Results show that neither content nor is reliable needles significant increased considerably throughout winter growing nursery beds. Seedlings lifted stored showed large reductions root due respiration, did not necessarily exhibit reduced potential field. Even some with very low were able survive on site. Any overall weak at best. failed test unable reliably damage, especially resulting from storage or desiccation. demonstrated severe freezing often results significantly elevated solute concentrations sap, apparently leakage cell solutes through ruptured membranes. However, below level associated does indicate are healthy. method may be quick easy way damaged by freezing. "standard" growth stress (OSU vigor) tests still most techniques estimate best single mean total length new after one month, which accounted for 51 percent variability THE STARCH CONTENT OF ROOTS AND OSMOTIC CONCENTRATION EXPRESSED XYLEM SAP AS PREDICTORS DOUGLAS-FIR SEEDLING QUALITY