Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu, Private Bag 11222, Palmerston North, 4442, New Zealand.
Environmental Sciences Group, School of Agriculture and Environment, Massey University, Manawatu, Private Bag 11222, Palmerston North, 4442, New Zealand.
Environ Pollut. 2021 Jan 1;268(Pt A):115839. doi: 10.1016/j.envpol.2020.115839. Epub 2020 Oct 14.
The two forage species used in New Zealand pastoral agricultural systems, chicory (Cichorium intybus) and plantain (Plantago lanceolata) show differential ability to absorb and translocate cadmium (Cd) from roots to shoots. Chicory can accumulate Cd from even low Cd soils to levels that might exceed regulatory guidelines for Cd in fodder crops and food. Chicory and plantain were grown in soil-filled rhizocolumns under increasing Cd levels (0 (Control), 0.4, 0.8 and 1.6 mg Cd/kg soil) for 60 days and showed variable secretion of oxalic, fumaric, malic and acetic acids as a function of Cd treatment. Plant roots secrete such Low Molecular Weight Organic Acids into the rhizosphere soil, which can influence Cd uptake. Chicory showed significantly (P < 0.05) lower secretion of fumaric acid, and higher secretion of acetic acid than plantain at all Cd treatments. We propose that the significant secretion differences between the two species can explain the significantly (P < 0.05) higher shoot Cd concentration in chicory for all Cd treatments. Understanding the mechanism for increased uptake in chicory may lead to breeding or genetic modification which yield low Cd uptake cultivars needed to mitigate the risk of Cd accumulation in pastoral agricultural food chains from this increasingly important fodder crop.
新西兰草地农业系统中使用的两种饲料作物，菊苣（Cichorium intybus）和车前草（Plantago lanceolata），显示出从根部向地上部吸收和转运镉（Cd）的不同能力。菊苣可以从即使是低 Cd 土壤中积累 Cd，达到可能超过饲料作物和食品中 Cd 监管指南规定的水平。菊苣和车前草在充满土壤的根柱中生长，Cd 水平逐渐增加（0（对照）、0.4、0.8 和 1.6 mg Cd/kg 土壤），持续 60 天，并表现出随着 Cd 处理而变化的草酸、富马酸、苹果酸和乙酸的分泌。植物根将这些低分子量有机酸分泌到根际土壤中，这会影响 Cd 的吸收。在所有 Cd 处理下，菊苣的富马酸分泌明显（P<0.05）低于车前草，而乙酸分泌明显（P<0.05）高于车前草。我们提出，两种物种之间的显著分泌差异可以解释在所有 Cd 处理下，菊苣地上部 Cd 浓度显著（P<0.05）更高的原因。了解菊苣中吸收增加的机制可能导致培育或遗传修饰，产生低 Cd 吸收品种，以减轻这种日益重要的饲料作物从草地农业食物链中积累 Cd 的风险。
