ABSTRACT

Atrazine, one of the most frequently applied herbicides in the world, is highly persistent, and likely to contaminate runoff and groundwater resources, determined by bioassay and chemical analyses. In the present research the two following experiments were conducted in Mazandaran Province, Iran. 1) The sensitivity of eight plant species (canola, soybean, ryegrass, wild oat, wheat, littleseed canarygrass, redroot pigweed, and corn) to atrazine residues in the laboratory of the Qaemshahr Campus of the Islamic Azad University in 2019 was determined. Bioassay and GR₅₀ index were used to differentiate species. 2) The leaching front of atrazine in the laboratory of Mazandaran University of Medical Sciences was determined. Soil samples were collected from a 10-hectare-farm of Baykola Agricultural Research Station. The method of undisturbed soil columns was used to study atrazine leaching at three levels including control, usual dose (1.25 kg. ha⁻¹), and high dose (2.5 kg. ha⁻¹). The treatments were injected into soil columns inside 32-cm-high PVC pipes and after three days, 2-cm segments of the soil columns were exposed to bioassay and chemical analyses, simultaneously. In the first experiment, plants response to atrazine residues were different. Canola and corn were the most susceptible and tolerant crop species, respectively. The tolerance of other plant species to total residue, using GR₅₀ index, was according to the following order: canola < soybean < ryegrass < wild oat < wheat < littleseed canarygrass < redroot pigweed < corn. According to the bioassay test, at the high dose of atrazine, all traits were negatively affected, and the root weight and the ratio of root to shoot weight had the highest and the lowest decrease (28% and 12% relative to control), respectively. The simultaneous investigation of canola seedling weight and atrazine concentration, at different soil depths, revealed that atrazine penetrated to the 10-cm depth, which is attributed to higher organic matter and clay content. Canola was identified as a suitable plant for atrazine bioassay. Due to the depths of weed seed distribution and leaching front of atrazine in this experiment (on average, 10 cm), the contamination of weed seed lot with herbicides can be high.

摘要

阿特拉津是世界上最常用的除草剂之一，具有高度持久性，并且可能会污染径流和地下水资源，这由生物测定和化学分析确定。在本研究中，以下两个实验是在伊朗马赞达兰省进行的。1) 2019年伊斯兰阿扎德大学Qaemshahr校区实验室测定了8种植物（油菜、大豆、黑麦草、野燕麦、小麦、小籽金丝雀草、红根藜和玉米）对阿特拉津残留的敏感性。生物测定和 GR ₅₀指数用于区分物种。2）马赞达兰医科大学实验室测定阿特拉津浸出前沿。土壤样本是从 Baykola 农业研究站 10 公顷的农场收集的。采用原状土柱法研究阿特拉津在对照、常用剂量（1.25 kg. ha ^-1）和高剂量（2.5 kg. ha ^{-1 ）三个水平下的浸出}）。将处理剂注入 32 厘米高的 PVC 管内的土壤柱中，三天后，将 2 厘米的土壤柱段同时进行生物测定和化学分析。在第一个实验中，植物对阿特拉津残留物的反应是不同的。油菜和玉米分别是最易感和最耐受的作物品种。其他植物物种对总残留物的耐受性，使用 GR ₅₀指数，按以下顺序排列：油菜 < 大豆 < 黑麦草 < 野燕麦 < 小麦 < 小金丝雀草 < 红根藜 < 玉米。根据生物测定试验，在阿特拉津高剂量下，所有性状均受到负面影响，根重和根冠比下降幅度最大和最低（相对于对照分别下降28%和12%） . 同时调查不同土壤深度的油菜幼苗重量和阿特拉津浓度表明，阿特拉津渗透到 10 cm 深度，这归因于较高的有机质和粘土含量。油菜被确定为适合阿特拉津生物测定的植物。由于本实验中杂草种子分布深度和莠去津浸出前沿（平均10 cm），