Quantifying the level of ecophysiological, biochemical, and agronomical fitness of herbicide-resistant (R) and herbicide-susceptible (S) weeds is useful for understanding the evolutionary development of herbicide resistance, but also for implementing herbicide-resistance management strategies. Although germination is a key fitness component in the life cycle of weeds, germinability of S and R weeds has rarely been evaluated under stressful conditions. Germinability traits of S and non–target site resistant subpopulations of blackgrass (Alopecurus myosuroides Huds.) sharing closely related genetic background were tested under salinity, drought stress, and accelerated seed-aging (i.e., exposed to 100% relative humidity at 45 C from 0 to 134 h) conditions. In addition, the activity of three antioxidant enzymes and protein concentration of accelerated aged seeds of the subpopulations were studied. There were no differences in maximum seed germination (Gmax) and time to 50% germination between the two subpopulations under optimum conditions. However, under salinity, drought stress, and accelerated aging conditions, there were differences between the subpopulations. The salinity, drought, and accelerated aging treatments reducing Gmax of the S subpopulation by 50% were 18 dS m−1, 0.75 MPa, and 90 h, respectively, while for the R subpopulation the corresponding values were 15 dS m−1, 0.66 MPa, and 67 h. No differences were found in the activity of the antioxidant enzymes and the content of protein between non-aged seeds of the subpopulations. The aging treatments reducing the activity of catalase and superoxide dismutase enzymes by 50% were 118 and 82 h for the S subpopulation, respectively, while they were 54 and 58 h for the R subpopulation. In contrast, there were no differences in the effect of the aging treatments on the peroxidase activity and protein content between subpopulations. The results provided clear evidence that the non–target site resistant loci of blackgrass is associated with fitness costs under environmental stress.

中文翻译：

---

暴露于非生物胁迫的易感和非靶点抗除草剂黑草（Alopecurus myosuroides）亚群的发芽力和种子生化特性

量化抗除草剂 (R) 和易除草剂 (S) 杂草的生态生理、生化和农艺适应性水平有助于了解除草剂抗性的进化发展，也有助于实施除草剂抗性管理策略。尽管发芽是杂草生命周期中的关键适应性组成部分，但很少在压力条件下评估 S 和 R 杂草的发芽能力。黑草 S 和非靶点抗性亚群的发芽性状 (大穗赤霉Huds.) 共享密切相关的遗传背景在盐度、干旱胁迫和加速种子老化（即，从 0 到 134 小时暴露于 45 C 下 100% 相对湿度）条件下进行测试。此外，还研究了亚群加速老化种子的三种抗氧化酶活性和蛋白质浓度。最大种子发芽率没有差异（G最大限度) 以及在最佳条件下两个亚群之间发芽 50% 的时间。然而，在盐分、干旱胁迫和加速老化条件下，亚群之间存在差异。盐度、干旱和加速老化处理减少G最大限度50% 的 S 亚群为 18 dS m-1、0.75 MPa 和 90 小时，而对于 R 亚群，相应的值为 15 dS m-1、0.66 兆帕和 67 小时。亚群非衰老种子的抗氧化酶活性和蛋白质含量无差异。使过氧化氢酶和超氧化物歧化酶活性降低 50% 的老化处理对 S 亚群分别为 118 和 82 小时，而对 R 亚群分别为 54 和 58 小时。相反，老化处理对亚群之间过氧化物酶活性和蛋白质含量的影响没有差异。结果提供了明确的证据，表明黑草的非靶点抗性基因座与环境压力下的适应成本相关。