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Li X, Zhang X, Wu Y, Li B, Yang Y. Physiological and biochemical analysis of mechanisms underlying cadmium tolerance and accumulation in turnip. Plant Divers 2018; 40:19-27. [PMID: 30159537 PMCID: PMC6091934 DOI: 10.1016/j.pld.2017.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 12/01/2017] [Accepted: 12/27/2017] [Indexed: 05/29/2023]
Abstract
The capacity of plants to accumulate cadmium (Cd) is significant for phytoremediation of Cd-polluted soils. Turnips cultivated in China include species featuring high Cd accumulation and some of these plants act as Cd hyperaccumulator landraces. These plants can accumulate over 100 mg Cd kg-1 dry weight in leaves without injury. Hence, studies that explore mechanisms underlying Cd detoxification and transport in turnip plants are essential. In the present study, we compared physiological and biochemical changes in turnip leaves treated with two Cd concentrations to controls. We discovered that Cd stress significantly increased the enzymatic activities or compound contents in the antioxidant system, including members of the glutathione-ascorbic acid cycle, whereas oxidation of reactive oxygen species (ROS) remained stable. Cd treatments also increased the contents of phytochelatins as well as a number of amino acids. Based on these results, we conclude that turnips initiate a series of response processes to manage Cd treatment. First, the antioxidant system maintaining ROS homeostasis and osmotic adjustment is excited to maintain stability of cell osmotic potential. Cd is chelated into its stable form to reduce its toxicity. Cd is possibly transported to vacuoles or non-protoplasts for isolation. Amino acid synthesis may directly and indirectly play an important role in these processes. This study partly revealed physiological and biochemical mechanisms underlying turnip response to Cd stress and provides information on artificially increasing or decreasing Cd accumulation in turnips and other plants.
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Key Words
- APX, ascorbate peroxidase
- Antioxidant system
- AsA, ascorbic acid
- CAT, catalase
- Cadmium
- Cd, cadmium
- DHAR, dehydroascorbate reductase
- DW, dry weight
- Detoxification
- FW, fresh weight
- GR, glutathione reductase
- GSH, glutathione
- GST, glutathione S-transferase
- H2O2, hydrogen peroxide
- HM, heavy metal
- MDA, malondialdehyde
- Ni, nickel
- O2-, superoxide anion
- PCs, phytochelatins
- POD, peroxidase
- Phytochelatin
- ROS, reactive oxygen species
- SOD, superoxide dismutase
- TCA, trichloroacetic acid
- Turnip
- Zn, zinc
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Affiliation(s)
- Xiong Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Xiaoming Zhang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuansheng Wu
- College of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - Boqun Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Yongping Yang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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