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重金属自然存在于土壤中,然而工农业生产等人为活动使其毒性水平广泛提高[1]。微量金属通过影响植物的生长、发育、开花,阻碍植物生产力,并通过食物链中的生物放大作用危害人类健康[2]。
Cd与Zn属于同族重金属元素,具有相似的地球化学和环境特性,常共存于土壤中。Cd没有生理功能,通过改变气孔运动和蒸腾作用阻碍植物生长,对植物有剧毒[3]。与Cd不同,Zn是一种必需元素,作为各种金属蛋白的辅助因子参与生理代谢[4]。然而过量的Zn也会导致生长抑制,叶片卷曲和叶尖坏死[5]。已有研究探讨了Cd、Zn胁迫作用下植物生长和重金属的吸收影响。如郭俊娒等[6]研究了不同Cd、Zn浓度胁迫作用对三七景天生长、根系形态及Cd、Zn吸收和积累的影响,研究发现三七景天具有较强的Cd富集能力;贾彦等[7]以金针菇为试验材料,研究了食用菌富集Cd、Zn以及其交互作用对食用菌累积重金属的影响;潘秀等[8]通过盆栽试验,研究了Cd、Zn及其交互作用下对互花米草生长、重金属吸收及亚细胞分布的影响。目前还没有关于Cd、Zn复合胁迫模式对长梗白菜的形态和生理性能影响研究。
与其他农作物(除水稻外[9])相比,由于绿叶蔬菜表面积大而更容易暴露在环境中受到污染[10],叶类蔬菜中积累的重金属浓度更高。长梗白菜作为普通食用蔬菜之一,与人们日常消费紧密相关。本次研究选择长梗白菜为研究对象,采用盆栽实验,通过分析生长抑制、脂质过氧化和抗氧化酶活性几个胁迫参数以及重金属吸收量,研究Cd、Zn胁迫对长梗白菜的影响。研究结果可为农田-植物系统中复合污染土壤重金属安全阈值研究和土壤重金属复合污染防治提供科学支撑。
Zn和Cd胁迫作用对长梗白菜形态和生理性能的生态毒理影响
Ecotoxicological effects of Zn and Cd stress on the morphology and physiological properties of long-stalk cabbage
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摘要: 本文以不同Cd、Zn浓度胁迫下的长梗白菜为研究对象,采用盆栽实验,分析了Cd和Zn胁迫下长梗白菜形态参数(重量、长度、表面积、叶的分形维数)、生理性能的影响以及从土壤中提取Cd和Zn的能力。结果表明,Cd、Zn胁迫对长梗白菜的生长具有“低促高抑”效应,且共同胁迫对生长的影响大于单一胁迫。在0.6 mg·kg−1 Cd和250 mg·kg−1 Zn同时胁迫下叶茎生物量分别增加93.27%和155.84%;当Cd、Zn同时胁迫下浓度分别升至0.9 mg·kg−1和350 mg·kg−1,叶茎生物量分别降低63%和66.23%。随重金属浓度的升高,植物中过氧化物酶(POD)的活性先升高后降低。与对照组相比,在150 mg·kg−1 Zn胁迫下POD活性提高了64.17%,在350 mg·kg−1 Zn胁迫下降低了31.50%。重金属处理导致长梗白菜中过氧化氢酶(CAT)活性不同程度升高。在0.9 mg·kg−1 Cd和350 mg·kg−1 Zn同时胁迫下达到最大活性99.74 U·g−1。Cd和Zn的联合处理显著降低了丙二醛(MDA)含量。Zn的添加促进Cd的吸收,根中Cd含量可达0.21 mg·kg−1。研究结果可为土壤重金属复合污染防治,提高蔬菜品质提供科学支撑。Abstract: In this paper, the long-stalk cabbage under different Cd and Zn concentration stresses was used as the research object. Potted experiments were used to analyze the morphological parameters (length, weight, surface area, leaf fractal dimension) and physiological properties of long-stemmed cabbage under Cd and Zn stress. Influence and the ability to extract Cd and Zn from the soil. The results showed that: Cd and Zn stress have a “low-promoting high-inhibition” effect on the growth of long-stemmed cabbage, and the common stress has a greater impact on the growth than a single stress. Under the simultaneous stress of 0.6 mg·kg−1 Cd and 250 mg·kg−1 Zn, the leaf and stem biomass increased by 93.27% and 155.84%, respectively; when Cd and Zn were simultaneously stressed, the concentration increased to 0.9 mg·kg−1 and 350, respectively mg·kg−1, the leaf and stem biomass decreased by 63% and 66.23%, respectively. As the concentration of heavy metals increases, the activity of peroxidase (POD) in plants first increases and then decreases. Compared with the control group, POD activity increased by 64.17% under 150 mg·kg−1 Zn stress, and decreased by 31.50% under 350 mg·kg−1 Zn stress. The treatment of heavy metals resulted in the increase of CAT activity in long-stemmed cabbage. The maximum activity of 99.74 U·g−1 was reached under the simultaneous stress of 0.9 mg·kg−1 Cd and 350 mg·kg−1 Zn. The combined treatment of Cd and Zn significantly reduced the content of malondialdehyde (MDA). The addition of Zn promotes the absorption of Cd, and the Cd content in the root can reach 0.21 mg·kg−1. The research results can provide scientific support for the prevention and control of soil heavy metal compound pollution and the improvement of vegetable quality.
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Key words:
- Cd /
- Zn /
- oxidative stress /
- heavy metal compounding stresses /
- long-stalk cabbage
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表 1 供试土壤的基本理化性质及重金属含量
Table 1. Basic physical and chemical properties and heavy metal content of the tested soil
pH 有机质/(g·kg−1)
Organic matterEC/
(ms·cm−1)黏粒/(g·kg−1)
Clay粉粒/(g·kg−1)
SiltZn/
(mg·kg−1)Cd/
(mg·kg−1)6.52 12.34±0.63 0.41±0.011 335.89±5.03 383.32±4.22 75.23±6.48 0.065±0.0019 表 2 Cd、Zn单一胁迫及其复合作用对长梗白菜生物量的影响
Table 2. Effects of single and combined stress of Cd and Zn on the biomass of long-stalk cabbage
处理组别
Treatment group叶生物量/g
Leaf biomass茎生物量/g
Stem biomass根生物量/g
Root biomassTI CK 3.27±0.04fg 1.54±0.08f 0.70±0.02e A1 4.38±0.18cd 2.55±0.12c 0.86±0.06c 1.41 A2 3.85±0.12e 1.85±0.08e 0.71±0.02e 1.16 A3 3.04±0.22f 1.36±0.04d 0.85±0.07c 1.17 B1 3.86±0.10e 2.22±0.08d 0.72±0.04e 1.23 B2 3.14±0.15fg 1.02±0.03h 0.42±0.04g 0.83 B3 3.16±0.03fg 1.23±0.14g 0.44±0.10g 0.88 C1 4.38±0.13d 2.24±0.07d 0.82±0.04cd 1.35 C2 6.32±0.23b 3.94±0.09a 0.65±0.10e 1.98 C3 1.21±0.04h 0.52±0.09i 0.18±0.02h 0.35 注∶数据为平均值±标准差,同一列不同字母代表差异显著(P<0.05).
Note∶ the data are mean ± SD, and different letters in the same column represent significant difference (P < 0.05).表 3 长梗白菜的形态参数
Table 3. Morphological parameters of long-stalk cabbage
处理组别
Treatment group根 Root 茎 Stem 叶 Leaf 长度/cm
Length直径/mm
Diameter长度/cm
Length长度/cm
Length宽度/cm
Width面积/cm2
AreaCK 10.61±3.6b 2.34±1.3abc 6.15±0.2a 14.79±3.4a 6.81±1.0a 61.05±29.1ab A1 10.64±3.2b 1.62±0.6cd 2.50±1.4bc 7.64±1.9c 4.52±1.0b 42.40±20.1b A2 11.47±3.3ab 2.78±1.5a 2.75±0.6bc 12.79±1.4ab 6.77±1.4a 68.05±22.7a A3 10.64±2.1b 1.49±0.8d 5.33±1.7abc 12.34±1.3ab 6.42±0.9a 55.48±11.8ab B1 10.38±1.7b 1.60±0.7cd 1.65±1.0c 10.84±1.2b 6.13±1.1a 44.68±12.5b B2 10.19±3.0b 1.66±0.9bcd 3.83±2.3b 10.26±4.6bc 4.41±1.7b 49.83±11.4ab B3 9.68±2.9b 1.99±1.2abcd 2.69±0.9bc 11.58±1.3b 6.05±0.6a 50.92±12.6ab C1 13.19±4.4a 1.72±0.9bcd 2.80±1.5bc 8.80±2.4bc 5.48±1.7ab 55.40±11.9ab C2 14.12±3.8a 2.15±0.7abcd 3.10±1.3bc 12.97±3.1ab 6.38±1.1a 61.54±25.0ab C3 13.43±2.4ab 2.71±1.1ab 1.57±0.8c 10.21±1.2bc 5.19±0.7ab 48.52±11.9ab 注∶数据为平均值±标准差,同一列不同字母代表差异显著(P<0.05).
Note∶ the data are mean ± SD, and different letters in the same column represent significant difference (P < 0.05).表 4 在不同浓度Cd和Zn胁迫下长梗白菜中Cd、Zn的富集、转运系数
Table 4. Enrichment and transport coefficient of Cd and Zn in long-stalk cabbage under different concentrations of Cd and Zn stress
处理组别
Treatment groupBCF TF根-茎 TF茎-叶 根 Root 茎 Stem 叶 Leaf Cd A1 0.34 0.27 0.21 0.78 0.80 A2 0.25 0.19 0.15 0.77 0.79 A3 0.22 0.16 0.12 0.73 0.77 C1 0.76 0.51 0.37 0.67 0.73 C2 0.46 0.29 0.20 0.63 0.68 C3 0.42 0.25 0.14 0.59 0.58 Zn B1 0.45 0.23 0.21 0.51 0.92 B2 0.32 0.21 0.18 0.64 0.85 B3 0.27 0.16 0.13 0.59 0.83 C1 0.39 0.20 0.18 0.50 0.91 C2 0.29 0.14 0.12 0.49 0.84 C3 0.25 0.12 0.10 0.48 0.82 -
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