Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain.
Ecotoxicol Environ Saf. 2011 Oct;74(7):2040-9. doi: 10.1016/j.ecoenv.2011.06.019. Epub 2011 Jul 16.
Spartina densiflora has demonstrated a high tolerance to heavy metal contamination and a high capacity for accumulating metal in its tissues. In the Gulf of Cadiz this species has colonized habitats with different degrees of metal pollution. The aim of this study is to analyse the responses of populations of Spartina densiflora to this pollution. Germination, growth, photosynthesis and metal uptake of two populations of Spartina densiflora collected from contaminated sites (Odiel and Tinto marshes) and of one population from a clean site (Piedras marshes) were examined through two reciprocal experiments, in which seeds and adult plants were exposed to metal-contaminated and uncontaminated soil under greenhouse conditions. The seeds of Spartina densiflora were able to germinate in all sediments with little differences between populations, even in more contaminated soils. However, these conditions decreased the growth and survival of the seedlings to a similar degree for all populations. Likewise, no differences were recorded in relation to physiological and metal uptake. Contrarily, in the adult experiment, we found that the Odiel population differed from the other populations in growth and metal uptake, with overall greater values. These differences in growth were strongly supported by lower photosynthetic rates and stomatal conductance in the Piedras and Tinto populations. The reduction in photosynthetic performance was largely due to the reduction in photosynthetic pigment concentration in both populations. Despite these differences, there was insufficient evidence to support that Spartina has evolved to heavy-tolerant ecotypes, since all Spartina densiflora populations proved to have a great capacity for accumulating heavy metals in its roots. Nonetheless, this finding suggests that the Odiel population could have a greater phytoremediation potential.
大米草表现出对重金属污染的高度耐受性和在其组织中积累金属的高能力。在加的斯湾，该物种已在不同程度受到金属污染的栖息地中定殖。本研究的目的是分析大米草种群对这种污染的反应。通过两个相互对照的实验，检查了从污染（奥德耶尔和廷托沼泽）和清洁（皮埃德拉斯沼泽）地区采集的两种大米草种群的种子和成年植物的萌发、生长、光合作用和金属吸收。在温室条件下，将种子和成年植物暴露于受污染和未受污染的土壤中，来进行这两个实验。大米草的种子能够在所有沉积物中萌发，不同种群之间几乎没有差异，即使在污染更严重的土壤中也是如此。然而，这些条件以相似的程度降低了所有种群幼苗的生长和存活率。同样，在生理和金属吸收方面没有记录到差异。相反，在成年植物实验中，我们发现奥德耶尔种群在生长和金属吸收方面与其他种群不同，总体上具有更高的值。这些生长差异得到了皮埃德拉斯和廷托种群较低的光合作用率和气孔导度的有力支持。光合作用性能的降低在很大程度上是由于两个种群中光合色素浓度的降低。尽管存在这些差异，但没有足够的证据支持大米草已经进化为耐重金属的生态型，因为所有大米草种群都被证明具有在其根部积累重金属的巨大能力。尽管如此，这一发现表明奥德耶尔种群可能具有更大的植物修复潜力。
Zotero 插件