Responses of trembling aspen (Populus tremuloides), jack pine (Pinus banksiana), and white spruce (Picea glauca) seedlings to root zone pH ranging from 5 to 9 were studied in sand culture in the presence of two mineral nutrition levels. After eight weeks of treatments, effects of pH on plant dry weights varied between the plant species and were relatively minor in white spruce. Higher nutrient supply significantly increased dry weights only in trembling aspen subjected to pH 5 treatment. There was little effect of pH and nutrition level on net photosynthesis and transpiration rates in white spruce and jack pine, but net photosynthesis markedly declined in aspen at high pH. Chlorophyll concentrations in young foliage decreased the most in trembling aspen and jack pine. The effects of high pH treatments on the concentrations of Mg, P, Ca, Mn, Zn, and Fe in young foliage varied between the plant species with no significant decreases of Fe and Zn recorded in trembling aspen and white spruce, respectively. This was in contrast to earlier reports from the studies carried out in hydroponic culture. The sand culture system that we developed could be a more suitable alternative to hydroponics to study plant responses to pH in the root zone. Plant responses to high pH appear to involve complex events with a likely contribution of nutritional effects and altered water transport processes.

中文翻译：

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pH 值和矿物质营养对沙培中颤杨 (Populus tremuloides)、短叶松 (Pinus Banksiana) 和白云杉 (Picea glauca) 幼苗生长和生理反应的影响。


研究了颤杨 ( Populus tremuloides )、短叶松 ( Pinus Banksiana ) 和白云杉 ( Picea glauca ) 幼苗对 5 至 9 范围内的根区 pH 值的反应，并在两种矿物质营养水平存在的情况下进行沙培养。经过八周的处理后，pH 对植物干重的影响因植物种类而异，并且对白云杉的影响相对较小。仅在经过 pH 5 处理的颤抖白杨中，更高的养分供应显着增加了干重。 pH值和营养水平对白云杉和短叶松的净光合作用和蒸腾速率影响不大，但高pH值下白杨的净光合作用显着下降。颤杨和短叶松幼叶中的叶绿素浓度下降幅度最大。高 pH 处理对不同植物幼叶中 Mg、P、Ca、Mn、Zn 和 Fe 浓度的影响存在差异，颤杨和白云杉中的 Fe 和 Zn 分别没有显着降低。这与早期水培研究的报告形成鲜明对比。我们开发的沙培养系统可能是水培法的更合适的替代方案，用于研究植物对根区 pH 值的反应。植物对高 pH 值的反应似乎涉及复杂的事件，可能会造成营养效应和改变水传输过程。