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Abstract：
BACKGROUND: A study on photosynthetic and enzyme activity changes and mineral content in lettuce under cadmium stress has been conducted in a greenhouse, utilizing the modulated effect of zinc (Zn) application in the nutrient solution on lettuce. Zn is a micronutrient that plays an essential role in various critical plant processes. Accordingly, three concentrations of Zn (0.022, 5, and 10 mg L- 1) were applied to hydroponically grown lettuce (Lactuca sativa L. cv. Ferdos) under three concentrations of Cd toxicity (0, 2.5, and 5 mg L- 1).
RESULTS: The results showed that along with increasing concentrations of zinc in the nutrient solution, growth traits such as plant performance, chlorophyll index (SPAD), minimum fluorescence (F0), leaf zinc content (Zn), leaf and root iron (Fe) content, manganese (Mn), copper (Cu), and cadmium increased as well. The maximum amounts of chlorophyll a (33.9 mg g- 1FW), chlorophyll b (17.3 mg g- 1FW), carotenoids (10.7 mg g- 1FW), maximum fluorescence (Fm) (7.1), and variable fluorescence (Fv) (3.47) were observed in the treatment with Zn without Cd. Along with an increase in Cd concentration in the nutrient solution, the maximum amounts of leaf proline (5.93 mmol g- 1FW), malondialdehyde (MDA) (0.96 μm g- 1FW), hydrogen peroxide (H2O2) (22.1 μm g- 1FW), and superoxide dismutase (SOD) (90.3 Unit mg- 1 protein) were recorded in lettuce treated with 5 mg L- 1 of Cd without Zn. Additionally, the maximum activity of leaf guaiacol peroxidase (6.46 Unit mg- 1 protein) was obtained with the application of Cd at a 5 mg L- 1 concentration.
CONCLUSIONS: In general, an increase in Zn concentration in the nutrient solution decreased the absorption and toxicity of Cd in lettuce leaves, as demonstrated in most of the measured traits. These findings suggest that supplementing hydroponic nutrient solutions with zinc can mitigate the detrimental effects of cadmium toxicity on lettuce growth and physiological processes, offering a promising strategy to enhance crop productivity and food safety in cadmium-contaminated environments.
RESULTS: The results showed that along with increasing concentrations of zinc in the nutrient solution, growth traits such as plant performance, chlorophyll index (SPAD), minimum fluorescence (F0), leaf zinc content (Zn), leaf and root iron (Fe) content, manganese (Mn), copper (Cu), and cadmium increased as well. The maximum amounts of chlorophyll a (33.9 mg g- 1FW), chlorophyll b (17.3 mg g- 1FW), carotenoids (10.7 mg g- 1FW), maximum fluorescence (Fm) (7.1), and variable fluorescence (Fv) (3.47) were observed in the treatment with Zn without Cd. Along with an increase in Cd concentration in the nutrient solution, the maximum amounts of leaf proline (5.93 mmol g- 1FW), malondialdehyde (MDA) (0.96 μm g- 1FW), hydrogen peroxide (H2O2) (22.1 μm g- 1FW), and superoxide dismutase (SOD) (90.3 Unit mg- 1 protein) were recorded in lettuce treated with 5 mg L- 1 of Cd without Zn. Additionally, the maximum activity of leaf guaiacol peroxidase (6.46 Unit mg- 1 protein) was obtained with the application of Cd at a 5 mg L- 1 concentration.
CONCLUSIONS: In general, an increase in Zn concentration in the nutrient solution decreased the absorption and toxicity of Cd in lettuce leaves, as demonstrated in most of the measured traits. These findings suggest that supplementing hydroponic nutrient solutions with zinc can mitigate the detrimental effects of cadmium toxicity on lettuce growth and physiological processes, offering a promising strategy to enhance crop productivity and food safety in cadmium-contaminated environments.
摘要：
背景：已经在温室中进行了有关镉胁迫下莴苣中光合作用和酶活性变化以及矿物质含量的研究，利用生菜营养液中锌（Zn）的调节作用。锌是一种微量营养素，在各种关键的植物过程中起着至关重要的作用。因此，将三种浓度的Zn（0.022、5和10mgL-1）施用于水培生菜（LactucasativaL.cv。Ferdos）在三种Cd毒性浓度（0、2.5和5mgL-1）下。
结果：结果表明，随着营养液中锌浓度的增加，生长性状，如植物性能，叶绿素指数（SPAD），最小荧光(F0)，叶片锌含量（Zn），叶和根铁（Fe）含量，锰(Mn),铜(Cu),镉也增加了。叶绿素a的最大含量（33.9mgg-1FW），叶绿素b（17.3mgg-1FW），类胡萝卜素（10.7mgg-1FW），最大荧光(Fm)(7.1)，在不含Cd的Zn处理中观察到可变荧光（Fv）（3.47）。随着营养液中Cd浓度的增加,叶脯氨酸的最大量（5.93mmolg-1FW），丙二醛（MDA）（0.96μmg-1FW），过氧化氢(H2O2)(22.1μmg-1FW),在用5mgL-1不含Zn的Cd处理的莴苣中记录到超氧化物歧化酶（SOD）（90.3单位mg-1蛋白）。此外,以5mgL-1浓度施用Cd可获得叶片愈创木酚过氧化物酶（6.46单位mg-1蛋白）的最大活性。
结论：一般来说，营养液中Zn浓度的增加降低了生菜叶片对Cd的吸收和毒性，正如大多数测量特征所证明的那样。这些发现表明，用锌补充水培营养液可以减轻镉毒性对莴苣生长和生理过程的不利影响，提供了一个有前途的战略，以提高镉污染环境中的作物生产力和食品安全。
结果：结果表明，随着营养液中锌浓度的增加，生长性状，如植物性能，叶绿素指数（SPAD），最小荧光(F0)，叶片锌含量（Zn），叶和根铁（Fe）含量，锰(Mn),铜(Cu),镉也增加了。叶绿素a的最大含量（33.9mgg-1FW），叶绿素b（17.3mgg-1FW），类胡萝卜素（10.7mgg-1FW），最大荧光(Fm)(7.1)，在不含Cd的Zn处理中观察到可变荧光（Fv）（3.47）。随着营养液中Cd浓度的增加,叶脯氨酸的最大量（5.93mmolg-1FW），丙二醛（MDA）（0.96μmg-1FW），过氧化氢(H2O2)(22.1μmg-1FW),在用5mgL-1不含Zn的Cd处理的莴苣中记录到超氧化物歧化酶（SOD）（90.3单位mg-1蛋白）。此外,以5mgL-1浓度施用Cd可获得叶片愈创木酚过氧化物酶（6.46单位mg-1蛋白）的最大活性。
结论：一般来说，营养液中Zn浓度的增加降低了生菜叶片对Cd的吸收和毒性，正如大多数测量特征所证明的那样。这些发现表明，用锌补充水培营养液可以减轻镉毒性对莴苣生长和生理过程的不利影响，提供了一个有前途的战略，以提高镉污染环境中的作物生产力和食品安全。
