College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
Pestic Biochem Physiol. 2024 May;201:105908. doi: 10.1016/j.pestbp.2024.105908. Epub 2024 Apr 10.
The inclination toward natural products has led to the onset of the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. Despite increasing knowledge coming to light of plant-derived materials as leads for new herbicides, relatively little is known about the mode of action on herbicide-resistant weeds. Cyanamide (CA) is a naturally occurring herbicide synthesized by hairy vetch (Vicia villosa Roth.). However, it has not been experimentally verified whether CA suppresses target plants via sustained discharge at low concentrations, as is often the case with most plant-derived materials. This study aimed to detect the toxicity and the mode of action of CA to alfalfa (Medicago sativa L.) and redroot pigweed (Amaranthus retroflexus L.). The toxicity of CA toward the alfalfa and redroot pigweed by three different exposure patterns was compared: low-concentration repeated exposure with 0.3 g/L CA (LRE), high-concentration single exposure with 1.2 g/L CA (HSE), and distilled water spray as control. The results showed that CA had a stronger inhibitory effect on redroot pigweed growth compared to alfalfa under both LRE and HSE exposure modes, with leaves gradually turning yellow and finally wilting. Beyond that, field trials were conducted to corroborate the toxicity of CA to alfalfa and redroot pigweed. The results have also shown that CA could inhibit the growth of redroot pigweed without significant adverse effects on alfalfa. The outcomes concerning electrolyte permeability, root activity, and malondialdehyde (MDA) content indicated that CA suppressed the growth of redroot pigweed by interfering with the structure of the cell membrane and impacting cellular osmotic potential. CA could destroy the cell membrane structure to inhibit the growth of the redroot pigweed by both LRE and HSE exposure modes, which provides a theoretical basis for preventing and controlling redroot pigweed in alfalfa fields.
对天然产物的倾向导致了新的生物活性代谢物的发现，这些代谢物可以针对特定的治疗或农业应用进行靶向。尽管越来越多的知识表明植物衍生材料是新型除草剂的先导，但对于除草剂抗性杂草的作用模式知之甚少。氰胺（CA）是毛野豌豆（Vicia villosa Roth.）合成的一种天然除草剂。然而，CA 是否通过低浓度下的持续放电来抑制靶标植物，就像大多数植物衍生材料那样，这还没有经过实验验证。本研究旨在检测 CA 对紫花苜蓿（Medicago sativa L.）和反枝苋（Amaranthus retroflexus L.）的毒性和作用模式。通过三种不同的暴露模式比较 CA 对紫花苜蓿和反枝苋的毒性：用 0.3 g/L CA（LRE）进行低浓度重复暴露、用 1.2 g/L CA（HSE）进行高浓度单次暴露，以及用蒸馏水喷雾作为对照。结果表明，CA 在 LRE 和 HSE 暴露模式下对反枝苋生长的抑制作用均强于紫花苜蓿，叶片逐渐变黄，最终萎蔫。此外，还进行了田间试验以证实 CA 对紫花苜蓿和反枝苋的毒性。结果还表明，CA 可以抑制反枝苋的生长，而对紫花苜蓿没有明显的不良影响。电解质渗透率、根活力和丙二醛（MDA）含量的结果表明，CA 通过干扰细胞膜结构和影响细胞渗透势来抑制反枝苋的生长。CA 可以通过 LRE 和 HSE 暴露模式破坏细胞膜结构来抑制反枝苋的生长，这为在紫花苜蓿田防控反枝苋提供了理论依据。
