Fan Shuan-Xi, Zhang Nan, Sun Min-Han, Hou Xian-Dong
Joint Technology Innovation Center for Land Engineering and Human Settlements of Shaanxi Land Engineering Construction Group Co., Ltd., and Xi'an Jiaotong University, Xi'an 710049, China.
Department of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China.
Huan Jing Ke Xue. 2024 Aug 8;45(8):4870-4882. doi: 10.13227/j.hjkx.202308262.
To screen for Pb, Zn, and Cd composite heavy metal hyperaccumulator plants, a survey, sampling, and analysis of dominant plants in typical lead-zinc mines and smelter areas in Baoji City were conducted. Potential Pb, Zn, and Cd composite heavy metal hyperaccumulator plants were initially screened, and a pot experiment of soil cultivation was carried out to observe the response characteristics of chlorophyll （chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll）, antioxidant enzymes （SOD, CAT, and POD）, and other physiological indicators （MDA and proline） under the stress of Pb, Zn, and Cd composite heavy metals. A field experiment was also conducted to further verify and determine their enrichment ability for Pb, Zn, and Cd composite heavy metals, aiming to provide scientific basis and technical support for the remediation of Pb, Zn, and Cd composite heavy metal-polluted soil. The field survey revealed that L. met the international hyperaccumulator plant index requirements for the enrichment of Pb, Zn, and Cd, with enrichment quantity, bioconcentration factor （BCF）, and transfer factor （TF） all meeting the requirements. It was a potential hyperaccumulator plant for Pb, Zn, and Cd composite heavy metals. The soil cultivation pot experiment showed that as the gradient of Pb, Zn, and Cd composite heavy metal stress increased, the content of chlorophyll a, chlorophyll b, and total chlorophyll in L. leaves gradually decreased, causing disruption to the plant's photosynthetic system when the gradient was greater than or equal to IV. The chlorophyll content in L. leaves exhibited a "low-stimulation-high-inhibition" phenomenon, while excessive stress stimulated the activation of its own protective systems, leading to reduced toxicity. In addition, there were significant differences （P < 0.05） in the content of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll between L. and L. both compared to the control treatment and between stress gradients. The SOD activity in the leaves of L. and L. showed a trend of increasing first, then decreasing, and then increasing. The CAT activity in the leaves of L. exhibited a "low-stimulation-high-inhibition" effect, whereas the CAT activity in the leaves of L. showed a trend of continuous decrease. The POD activity in the leaves of L. generally increased, whereas in the leaves of L., it increased first, then decreased, and then increased. The MDA content in the leaves of L. generally decreased, whereas in the leaves of L., it exhibited an upward trend. In addition, whether compared to the control between stress gradients, there were significant differences （ < 0.05） in the SOD, CAT, POD, MDA, and proline content of L. and L. The field experiment results indicated that L. could meet the hyperaccumulator plant index requirements for the enrichment of Pb, Zn, and Cd, making it a potential germplasm resource for Pb, Zn, and Cd composite heavy metal hyperaccumulator plants. It can be an ideal choice for the remediation of Pb, Zn, and Cd composite heavy metal-polluted soil.
为筛选铅、锌、镉复合重金属超富集植物，对宝鸡市典型铅锌矿及冶炼区的优势植物进行了调查、采样与分析。初步筛选出潜在的铅、锌、镉复合重金属超富集植物，并进行土壤栽培盆栽试验，观察铅、锌、镉复合重金属胁迫下叶绿素（叶绿素a、叶绿素b、类胡萝卜素和总叶绿素）、抗氧化酶（超氧化物歧化酶、过氧化氢酶和过氧化物酶）及其他生理指标（丙二醛和脯氨酸）的响应特征。还进行了田间试验，进一步验证并确定其对铅、锌、镉复合重金属的富集能力，旨在为铅、锌、镉复合重金属污染土壤的修复提供科学依据和技术支持。田间调查发现，某植物符合铅、锌、镉富集的国际超富集植物指标要求，富集量、生物富集系数和转运系数均满足要求。它是一种潜在的铅、锌、镉复合重金属超富集植物。土壤栽培盆栽试验表明，随着铅、锌、镉复合重金属胁迫梯度的增加，该植物叶片中叶绿素a、叶绿素b和总叶绿素含量逐渐降低，当梯度大于或等于IV时，对植物光合系统造成破坏。该植物叶片中叶绿素含量呈现“低刺激-高抑制”现象，而过度胁迫刺激了其自身保护系统的激活，导致毒性降低。此外，与对照处理相比以及在胁迫梯度之间，该植物与另一植物在叶绿素a、叶绿素b、类胡萝卜素和总叶绿素含量上存在显著差异（P<0.05）。该植物和另一植物叶片中的超氧化物歧化酶活性呈现先升高、后降低、再升高的趋势。该植物叶片中的过氧化氢酶活性呈现“低刺激-高抑制”效应，而另一植物叶片中的过氧化氢酶活性呈现持续下降趋势。该植物叶片中的过氧化物酶活性总体上增加，而另一植物叶片中的过氧化物酶活性先增加、后降低、再增加。该植物叶片中的丙二醛含量总体上降低，而另一植物叶片中的丙二醛含量呈现上升趋势。此外，无论是与对照相比还是在胁迫梯度之间，该植物和另一植物在超氧化物歧化酶、过氧化氢酶过氧化物酶、丙二醛和脯氨酸含量上存在显著差异（<0.05）。田间试验结果表明，该植物能够满足铅、锌、镉富集的超富集植物指标要求，是一种潜在的铅、锌、镉复合重金属超富集植物种质资源。它可以成为修复铅、锌、镉复合重金属污染土壤的理想选择。
