Toppi Luigi Sanità di, Musetti Rita, Marabottini Rosita, Corradi Maria Grazia, Vattuone Zulema, Favali Maria Augusta, Badiani Maurizio
Dipartimento di Biologia Evolutiva e Funzionale, Sezione di Biologia Vegetale, Università di Parma, viale delle Scienze 11 / A, I-43100 Parma, Italy.
Dipartimento di Biologia Applicata alla Difesa delle Piante, Università di Udine, via delle Scienze 208, I-33100 Udine, Italy.
Funct Plant Biol. 2004 May;31(4):329-338. doi: 10.1071/FP03171.
Thalli of the lichen Xanthoria parietina (L.) Th. Fr. were soaked for either 24 or 48 h in a buffered medium in the presence of environmentally relevant concentrations (4.8 and 9.6 μM) of hexavalent chromium [Cr(VI)]. Treatment effects on the antioxidant status, differential distribution and fate of Cr(VI) among the mycobiont and the photobiont cells, and potential damage to cell ultrastructure in the two bionts, were evaluated. The adopted conditions of low Cr(VI) stress caused: (i) an increase in the level of ascorbic acid and a decrease in that of reduced glutathione, as well as a moderate increase in guaiacol peroxidase activity, only observed after treatment with 9.6 μM Cr(VI); (ii) no changes in malondialdehyde content; (iii) a remarkable Cr accumulation in the mycobiont cytosol and compartmentalisation in the mycobiont vacuoles;(iv) a modest apoplastic Cr immobilisation by the outer part of the cell walls, of both the mycobiont and the photobiont. The response of X.parietina to low concentrations of Cr(VI) appears to be a complex phenomenon, which might reflect maintenance of cellular homeostatic equilibria, rather than specific response pathways.
地衣石黄衣（Xanthoria parietina (L.) Th. Fr.）的叶状体在含有环境相关浓度（4.8和9.6 μM）六价铬[Cr(VI)]的缓冲介质中浸泡24或48小时。评估了处理对抗氧化状态、Cr(VI)在菌共生体和光共生体细胞间的差异分布及归宿，以及对两种共生体细胞超微结构的潜在损伤的影响。所采用的低Cr(VI)胁迫条件导致：（i）抗坏血酸水平升高，还原型谷胱甘肽水平降低，以及仅在用9.6 μM Cr(VI)处理后观察到的愈创木酚过氧化物酶活性适度增加；（ii）丙二醛含量无变化；（iii）菌共生体细胞溶质中Cr显著积累，并在菌共生体液泡中进行区室化；（iv）菌共生体和光共生体细胞壁外部对Cr进行适度的质外体固定。石黄衣对低浓度Cr(VI)的反应似乎是一个复杂的现象，这可能反映了细胞稳态平衡的维持，而非特定的反应途径。
