title: Changes in subcellular distribution and antioxidant compounds involved in Pb accumulation and detoxification in Neyraudia reynaudiana.
abstract: The effects of increasing concentrations of lead (Pb) on Pb accumulation, subcellular distribution, ultrastructure, photosynthetic characteristics, antioxidative enzyme activity, malondialdehyde content, and phytochelatin contents were investigated in Neyraudia reynaudiana seedlings after a 21-day exposure. A Pb analysis at the subcellular level showed that the majority of Pb in the roots was associated with the cell wall fraction, followed by the soluble fraction. In contrast, the majority of the Pb in the leaves was located in the soluble fraction based on transmission electron microscopy and energy dispersive X-ray analyses. Furthermore, high Pb concentrations adversely affected N. reynaudiana cellular structure. The changes in enzyme activity suggested that the antioxidant system plays an important role in eliminating or alleviating Pb toxicity, both in the roots and leaves of N. reynaudiana. Additionally, the phytochelatin contents in the roots and leaves differed significantly between Pb-spiked treatments and control plants. Our results provide strong evidence that cell walls restrict Pb uptake into the protoplasm and establish an important protective barrier. Subsequent vacuolar compartmentalization in leaves could isolate Pb from other substances in the cell and minimize Pb toxicity in other organelles over time. These results also demonstrated that the levels of antioxidant enzymes and phytochelatin in leaves and roots are correlated with Pb toxicity. These detoxification mechanisms promote Pb tolerance in N. reynaudiana.
authors: College of Forestry, Fujian Agriculture and Forestry University, Co-innovation center for soil and water conservation in red soil region of the Cross-straits, Fuzhou, 350002, China.
authors: Chuifan
authors: C
authors: Zhou
authors: College of Forestry, Fujian Agriculture and Forestry University, Co-innovation center for soil and water conservation in red soil region of the Cross-straits, Fuzhou, 350002, China.
authors: Meiying
authors: M
authors: Huang
authors: College of Forestry, Fujian Agriculture and Forestry University, Co-innovation center for soil and water conservation in red soil region of the Cross-straits, Fuzhou, 350002, China.
authors: Ying
authors: Y
authors: Li
authors: College of Forestry, Fujian Agriculture and Forestry University, Co-innovation center for soil and water conservation in red soil region of the Cross-straits, Fuzhou, 350002, China.
authors: Jiewen
authors: J
authors: Luo
authors: College of Forestry, Fujian Agriculture and Forestry University, Co-innovation center for soil and water conservation in red soil region of the Cross-straits, Fuzhou, 350002, China. fjclp@126.com.
authors: Li Ping
authors: LP
authors: Cai
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D008658:Inactivation, Metabolic; D007854:Lead / Q000378:metabolism* / Q000633:toxicity; D008315:Malondialdehyde / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D054811:Phytochelatins / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D006109:Poaceae / Q000187:drug effects* / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects; D012989:Soil Pollutants / Q000378:metabolism / Q000633:toxicity
chemical_list: D000975:Antioxidants; D012989:Soil Pollutants; D007854:Lead; D008315:Malondialdehyde; D054811:Phytochelatins
keywords: Antioxidative defense system; Lead; Neyraudia reynaudiana; Phytochelatin; Subcellular distribution; Ultrastructure