Physiological responses of planting frozen and thawed Douglas-fir seedlings

Abstract

We studied the short-term (7-day) physiological responses of planting thawed and frozen root plugs of Douglas-fir (Pseudotsuga menziesii) seedlings in 2 separate experiments under cool-moist and warm-dry growing conditions, respectively. Our results showed that shoot water potential, root hydraulic conductance, net photosynthesis (A), and transpiration (E) were significantly lower in frozen seedlings compared with thawed seedlings under both growing conditions. Chlorophyll fluorescence values in frozen and thawed seedlings were similar throughout the measurement period at both growing conditions except at 0 hours. We detected no significant differences in electrolyte leakage and chlorophyll content between frozen and thawed seedlings under both environmental regimes. When planted under warm-dry conditions, thawed seedlings had more buds that began to elongate and had more new roots than frozen-planted seedlings at the end of the experiment. When planted in cool-moist conditions, however, neither frozen nor thawed seedlings had buds that resumed growth. Comparatively higher photosynthesis rates observed in thawed seedlings planted under warm-dry conditions might have contributed toward the production of more new roots, and could be advantageous for survival and early growth after outplanting.

Parent Publication

• National Proceedings: Forest and Conservation Nursery Associations-2007

Citation

Islam, M. Anisul; Apostol, Kent G.; Jacobs, Douglass F.; Dumroese, R. Kasten. 2008. Physiological responses of planting frozen and thawed Douglas-fir seedlings. In: Dumroese, R. K.; Riley, L. E., tech. coords. National Proceedings: Forest and Conservation Nursery Associations-2007. Proc. RMRS-P-57. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 126-134