Smit J, Van Den Driessche R
Department of Biology, University of Victoria, P.O. Box 1700, Victoria, B.C. V8W 2Y2, Canada.
Tree Physiol. 1992 Dec;11(4):401-10. doi: 10.1093/treephys/11.4.401.
One-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and lodgepole pine (Pinus contorta Dougl.) seedlings were grown for 17 weeks in 100-cm deep, 7.8-liter containers. Two Douglas-fir provenances, one from a wet and one from a dry site in coastal British Columbia, and two lodgepole pine provenances, one from a wet and one from a dry site in interior British Columbia, were grown in wet (522% water content) or dry (318% water content) peat/vermiculite soil in a factorial design. Each container was sealed so that water loss occurred only through the seedling. Five harvests were made at three to five week intervals and water use, dry matter increment, root length and root weight were determined at each harvest. Stomatal conductance and shoot water potentials were measured during the last 12 weeks of the experiment. Lodgepole pine seedlings had greater dry matter production, water use, stomatal conductance and new root length than Douglas-fir seedlings. New root weight of lodgepole pine seedlings exceeded that of Douglas-fir seedlings during the last five weeks of the experiment, and specific root length (root length per unit root weight) of new roots was higher for lodgepole pine seedlings throughout the experiment. Douglas-fir seedlings showed higher water use efficiency (WUE) than lodgepole pine seedlings, and both species showed higher WUE in the dry soil treatment. Douglas-fir seedlings had lower water potentials and higher water uptake rates per unit of new root length than lodgepole pine seedlings, although water uptake rates per unit of root dry weight showed little difference between species. Soil water treatment influenced specific root length of new roots, water uptake per unit of new root length, and WUE in Douglas-fir seedlings more than in lodgepole pine seedlings.
将一年生花旗松（Pseudotsuga menziesii (Mirb.) Franco）和扭叶松（Pinus contorta Dougl.）幼苗种植在深度为100厘米、容积为7.8升的容器中，培养17周。采用析因设计，将来自不列颠哥伦比亚省沿海一个湿润地点和一个干燥地点的两个花旗松种源，以及来自不列颠哥伦比亚省内陆一个湿润地点和一个干燥地点的两个扭叶松种源，种植在湿润（含水量522%）或干燥（含水量318%）的泥炭/蛭石土壤中。每个容器都进行了密封处理，以使水分仅通过幼苗流失。每隔三到五周进行五次收获，并在每次收获时测定水分利用、干物质增量、根长和根重。在实验的最后12周内测量气孔导度和地上部分水势。扭叶松幼苗比花旗松幼苗具有更高的干物质产量、水分利用、气孔导度和新根长度。在实验的最后五周，扭叶松幼苗的新根重量超过了花旗松幼苗，并且在整个实验过程中，扭叶松幼苗新根的比根长（单位根重的根长）更高。花旗松幼苗比扭叶松幼苗表现出更高的水分利用效率（WUE），并且在干旱土壤处理中，两个物种都表现出更高的WUE。花旗松幼苗的水势较低，单位新根长度的水分吸收速率高于扭叶松幼苗，尽管单位根干重的水分吸收速率在两个物种之间差异不大。土壤水分处理对花旗松幼苗新根的比根长、单位新根长度的水分吸收和WUE的影响比对扭叶松幼苗的影响更大。
