Department of Plant Physiology, Faculty of Horticulture and Landscape Architecture, Lublin University of Life Sciences, Akademicka 15, 20-950 Lublin, Poland.
Biol Trace Elem Res. 2013 May;152(2):251-7. doi: 10.1007/s12011-013-9606-y. Epub 2013 Jan 25.
Lithium (Li) is a trace element that is essential in the human diet due to its importance for health and proper functioning of an organism. However, the biological activity of this metal in crop plants, which are the primary dietary sources of Li, is still poorly understood. The aim of the presented study was to comparatively analyse two Li chemical forms on the growth, as well as the L-ascorbic acid content, the Li accumulation and translocation in butterhead lettuce (Lactuca sativa L. var. capitata) cv. Justyna. The plants were grown in a nutrient solution enriched with Li in the form of LiCl or LiOH at the following concentrations: 0, 2.5, 20, 50 or 100 mg Li dm(-3). The obtained results indicate that the presence of Li(+) ions in the root environment reduced the yield of edible parts of the lettuce if the Li concentration in a nutrient solution had reached 20 mg Li dm(-3). However, a yield reduction under these conditions was found to be significant only for LiOH. In plants exposed to 50 mg Li dm(-3), both shoot and root fresh weights (FW) significantly decreased, regardless of the supplied Li chemical form. On the other hand, under the lowest LiOH dose, a significant increase in the root FW was noted, suggesting beneficial effects of Li on the growth of lettuce plants. However, applied Li concentrations and forms did not affect the L-ascorbic acid content in the lettuce leaves. Regardless of which Li form was used, Li accumulated mainly in the root tissues. An exception was the higher concentration of this metal in the shoots than in the roots of plants supplied with 100 mg Li dm(-3) in LiCl, and there were almost the same Li concentrations in both examined organs of plants supplied with 100 mg Li dm(-3) in LiOH. The effectiveness of Li translocation from roots to shoots rose with increasing Li concentrations in the growth medium, and this suggests a relatively ready translocation of this metal throughout the plant. Moreover, these results suggest that Li toxicity in lettuce plants is related to a high accumulation of this element in the root and shoot tissues, causing a drastic reduction in the yield, in the presence either of LiCl or LiOH, but not affecting the L-ascorbic acid accumulation in the leaves.
锂（Li）是一种微量元素，对人体健康和正常机能至关重要，因此也是人类饮食中的必需元素。然而，这种金属在作物中的生物活性，也就是作物作为锂的主要饮食来源的生物活性，仍然知之甚少。本研究的目的是比较分析两种锂化学形态对生菜（Lactuca sativa L. var. capitata）cv. Justyna 的生长、抗坏血酸含量、锂积累和转运的影响。将植物种植在富锂的营养液中，锂的化学形态为 LiCl 或 LiOH，浓度分别为 0、2.5、20、50 或 100mgLi dm(-3)。研究结果表明，如果营养液中的 Li 浓度达到 20mgLi dm(-3)，Li(+)离子在根环境中的存在会降低生菜可食用部分的产量。然而，只有在这些条件下 LiOH 才会导致显著减产。在暴露于 50mgLi dm(-3)的植物中，无论是地上部分还是根的鲜重（FW）都显著下降，而与供应的 Li 化学形态无关。另一方面，在最低 LiOH 剂量下，根 FW 显著增加，表明 Li 对生菜生长有有益的影响。然而，施用的 Li 浓度和形态并未影响生菜叶片中的抗坏血酸含量。无论使用哪种 Li 形态，Li 主要积累在根组织中。例外的是，在 100mgLi dm(-3)LiCl 处理的植物中，茎中的 Li 浓度高于根，而在 100mgLi dm(-3)LiOH 处理的植物中，两个器官中的 Li 浓度几乎相同。随着生长介质中 Li 浓度的增加，Li 从根部向地上部分的转运效率也随之提高，这表明这种金属在植物中的转运相对容易。此外，这些结果表明，生菜植物中的 Li 毒性与该元素在根和地上组织中的高积累有关，导致在存在 LiCl 或 LiOH 的情况下产量大幅下降，但不影响叶片中抗坏血酸的积累。
