科研之友
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摘要
Metal hyperaccumulators are plants that store heavy metals or metalloids in their leaves, often to concentrations much higher than in the soil. Though most occur exclusively on metalliferous soils, some species are facultative, occurring on both metalliferous and nonmetalliferous soils. Psychotria grandis Sw.(Rubiaceae) occurs from Central America through the Caribbean on many soil types, and hyperaccumulates nickel (Ni) on serpentine soils in several localities. In this study, four Puerto Rican populations of P. grandis - two from serpentine soil and two from non-serpentine soil - were examined to compare Ni accumulation between and within populations. Multiple trees were sampled at most sites, with replicate leaves harvested from each tree. Foliar nickel concentrations were measured by atomic absorption spectrometry. Mean Ni concentration differed significantly among the sites, ranging from <165 mu gg(-1) on non-serpentine soil to >4000 mu gg(-1) on serpentine soil. There were also significant differences in Ni concentration among trees within sites, with especially wide variation at one of the serpentine sites known to be geologically heterogeneous. Despite these differences in field-collected leaves, a hydroponic common-garden experiment indicated that the Ni accumulation capacities of the populations were approximately equal. Variation in Ni accumulation between and within these populations in the field is likely to result from variation in Ni availability in the soil.
- 出版日期2015
