ABSTRACT Amaranthus is a versatile plant used as a food, but it is also a recognised weed due to its competitive ability. Amaranthus is very nutritious and preferred by rural communities as a leafy vegetable, but it also contains anti-nutritional components and there are reports of allelopathic activity. This study investigated the effects of Amaranthus on seed germination, and the effects of Amaranthus grown in pots and in the field on follow-up crops planted in the same soil. Extracts of the whole plant, stems, leaves, flowers and roots of Amaranthus exhibited severe inhibition of seed germination of vegetables, as well as of weed seeds of Conyza bonariensis. Significant allelopathic effects were observed on tomato seedlings in the pot experiment with reduced growth in two of the treatments. However, no significant effects were observed in any of the field trials. All of the Amaranthus extracts exhibited very high electrical conductivity (EC) value. In a dilution experiment, the diluted extracts exhibited lower EC values, with no or limited seed germination at concentrations higher than 3.12 mg ml−1 and corresponding EC value of 2.1 mS cm−1. The high EC values that were associated with the allelopathic effect, possibly resulted from allelochemicals in the plant, but these were not identified in this study. The origin and persistence of the allelopathic effect warrant further research to determine the risks for agricultural crops.

中文翻译：

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苋菜对蔬菜种子萌发、生长发育的化感作用

摘要 苋菜是一种用途广泛的植物，可用作食物，但由于其竞争能力，它也是一种公认​​的杂草。苋菜营养丰富，作为叶菜深受农村社区的青睐，但它也含有抗营养成分，并且有化感作用的报道。本研究调查了苋菜对种子萌发的影响，以及在盆栽和田间种植的苋菜对同一土壤中种植的后续作物的影响。苋菜全株、茎、叶、花和根的提取物对蔬菜种子萌发以及Conyza bonariensis杂草种子的萌发有严重的抑制作用。在盆栽试验中观察到对番茄幼苗的显着化感作用，其中两种处理的生长减少。然而，在任何田间试验中均未观察到显着影响。所有苋菜提取物都表现出非常高的电导率 (EC) 值。在稀释实验中，稀释的提取物表现出较低的 EC 值，在高于 3.12 mg ml-1 的浓度和相应的 EC 值为 2.1 mS cm-1 时没有或有限的种子发芽。与化感作用相关的高 EC 值可能是由植物中的化感化学物质引起的，但在本研究中未确定。化感作用的起源和持久性需要进一步研究以确定农作物的风险。在浓度高于 3.12 mg ml-1 和相应的 EC 值为 2.1 mS cm-1 时没有或有限的种子发芽。与化感作用相关的高 EC 值可能是由植物中的化感化学物质引起的，但在本研究中未确定。化感作用的起源和持久性需要进一步研究以确定农作物的风险。在浓度高于 3.12 mg ml-1 和相应的 EC 值为 2.1 mS cm-1 时没有或有限的种子发芽。与化感作用相关的高 EC 值可能是由植物中的化感化学物质引起的，但在本研究中未确定。化感作用的起源和持久性需要进一步研究以确定农作物的风险。