Miller S P, Cumming J R
Department of Biology, P.O. Box 6057, West Virginia University, Morgantown, WV 26506-6057, USA.
Tree Physiol. 2000 Oct;20(16):1129-35. doi: 10.1093/treephys/20.16.1129.
Effects of simulated serpentine soil conditions (elevated Mg:Ca ratio and Ni concentration) on seedlings from populations of Virginia pine (Pinus virginiana Mill.) from serpentine and non-serpentine sites were evaluated in sand culture. We determined (1) how seedlings are affected by elevated Mg:Ca ratio and Ni concentrations, (2) if there are interactive effects between Mg:Ca ratio and Ni concentrations on seedling growth, needle pigment concentrations, and nutrition, and (3) if Virginia pine populations from serpentine areas are edaphic ecotypes. A Mg:Ca ratio of 5 and 50 microM Ni both reduced seedling growth compared with control seedlings grown in the presence of the standard Mg:Ca ratio of 0.5 and no Ni. Interactive effects between Mg:Ca ratio and Ni concentrations were highly significant for growth, foliar pigments, and needle and root elemental concentrations. Nickel-mediated reductions in growth and foliar pigment concentrations were less at the serpentine Mg:Ca ratio of 5 than at the standard (non-serpentine) Mg:Ca ratio of 0.5. Foliar N was reduced by Ni concentrations as low as 10 microM, and foliar and root K, Ca and P concentrations were significantly reduced by Ni concentrations above 25 microM, with greater reductions at a Mg:Ca ratio of 0.5 than at a Mg:Ca ratio of 5. There were no population x serpentine soil factor interactions for seedling growth, foliar pigment concentrations, or nutrition, suggesting that seedlings from trees growing on serpentine soils are not edaphic ecotypes. We conclude that serpentine conditions present at the site of seed collection have not resulted in the selection of edaphic ecotypes of Virginia pine with respect to Mg:Ca ratio and Ni concentration.
在砂培条件下评估了模拟蛇纹石土壤条件（镁钙比升高和镍浓度升高）对来自蛇纹石和非蛇纹石地点的弗吉尼亚松（Pinus virginiana Mill.）种群幼苗的影响。我们确定了：（1）幼苗如何受到镁钙比升高和镍浓度升高的影响；（2）镁钙比和镍浓度对幼苗生长、针叶色素浓度和营养状况是否存在交互作用；（3）来自蛇纹石地区的弗吉尼亚松种群是否为土壤生态型。与在标准镁钙比0.5且无镍条件下生长的对照幼苗相比，镁钙比为5和镍浓度为50微摩尔时均降低了幼苗生长。镁钙比和镍浓度之间的交互作用对生长、叶片色素以及针叶和根系元素浓度具有高度显著影响。镍介导的生长和叶片色素浓度降低在蛇纹石镁钙比为5时比在标准（非蛇纹石）镁钙比为0.5时要小。镍浓度低至10微摩尔时会降低叶片氮含量，镍浓度高于25微摩尔时，叶片和根系的钾、钙和磷浓度会显著降低，在镁钙比为0.5时的降低幅度大于镁钙比为5时。在幼苗生长、叶片色素浓度或营养方面不存在种群×蛇纹石土壤因子的交互作用，这表明生长在蛇纹石土壤上的树木的幼苗不是土壤生态型。我们得出结论，种子采集地点存在的蛇纹石条件并未导致在镁钙比和镍浓度方面选择出弗吉尼亚松的土壤生态型。
