叶面喷施锌、硅对莴笋镉累积的影响

    Effect of Zinc/ Silicon Foliar Sprays on Cadmium Accumulation in Lettuce Plants

    • 摘要: 为探索叶面喷施锌(Zn)、硅(Si)阻控剂对减少轻污染土壤中莴笋Cd累积的效应,对Cd在莴笋各器官的积累、亚细胞的分布以及形态变化等开展了研究。结果表明,叶面喷施Zn、Si后,可食部位Cd含量可降低10.51%~45.09%,喷施Zn阻控剂和60 mmol·L-1 Si阻控剂的处理莴笋可食部位Cd含量均低于GB 2762—2017《食品安全国家标准食品中污染物限量》;阻控剂施用浓度是影响莴笋Cd累积的主要因素,高浓度阻控剂降Cd效果优于低浓度;叶面喷施处理促进Cd由活性态向非活性态转化,莴笋各器官的氯化钠提取态Cd占比显著增加,根、茎、叶活性态Cd含量占比分别降低75.83%、60.38%、80.03%;叶面喷施均显著减少根部细胞器Cd的分配比例,茎、叶部细胞器Cd分配比例降幅达30%以上。叶面喷施Zn、Si降低了重金属Cd在莴笋根部的活性,进而阻控Cd在莴笋可食部位的积累。

       

      Abstract: The objective of this study is to explore the effect of applying zinc (Zn) and silicon (Si) as foliar sprays on the accumulation of cadmium (Cd) in lettuce plants growing in lightly Cd-polluted soil. The Cd contents in various organs of lettuce and its subcellular distribution patterns were determined, and the morphological responses of lettuce plants were analyzed. The results of the study show that foliar spraying with Zn and Si reduced the Cd contents in edible parts of lettuce plants by 10.51%-45.09%. The Cd content in the edible parts of lettuce treated with Si was lower than the limit specified in the national food safety standard. The concentration of Zn/Si was the main factor affecting the accumulation of Cd in lettuce, with higher concentrations having a stronger effect to reduce Cd accumulation. Foliar spraying with Si or Zn promoted the conversion of Cd from an active to an inactive state, significantly increased the proportion of sodium chloride-extracted Cd in various organs of lettuce, and reduced the proportion of active Cd in the roots, stems, and leaves by 75.83%, 60.38%, and 80.03%, respectively. Foliar spraying with Si or Zn significantly reduced the distribution of Cd in root organelles, and reduced the distribution of Cd in stem and leaf organelles by more than 30%. Foliar spraying with Zn and Si could reduce the activity of the heavy metal Cd in lettuce roots and prevent and control Cd accumulation in the edible parts of lettuce plants.

       

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