Cutleaf geranium is a weed infesting crop fields in various parts of the world. The present study was conducted to determine the cardinal temperatures of germination for its seeds to have a better understanding about temperature needs of this species. Since the seeds were dormant after being harvested, they underwent different dormancy breaking methods. Then, cardinal temperatures were estimated. Among dormancy breaking methods including constant and alternating temperatures, gibberellic acid, H2SO4 and gibberellic acid+ H2SO4 treatments, pre-chilling and after-ripening, after-ripening was the most successful one. Dent and segmented models were the most suitable models for determination of cardinal temperatures. Base, optimum, and ceiling temperatures for dent model were estimated 0.02, 18.97 to 25.32, and 27.00 °C, respectively. These values for segmented model were 0.01, 24.3 and 27.08 °C. The seeds showed high germination uniformity at 15 and 20 °C, but they entered into a state of thermo-dormancy as temperature reached about 27 °C. According to the temperature conditions of the studied region, early sowing of canola will result in the weed being faced with higher than ceiling temperatures. Thus, generalizing, the proper sowing date may be regarded as a feasible management practice in controlling this weed in any given area. This was the first report on estimation of cardinal temperatures in cutleaf geranium.

中文翻译：

---

研究温度对切叶天竺葵（Geranium dissectum L.）种子萌发的影响及其基本温度的测定

Cutleaf天竺葵是一种杂草侵扰世界各地的农田。本研究旨在确定其种子发芽的基本温度，以便更好地了解该物种的温度需求。由于种子在收获后处于休眠状态，因此它们经历了不同的休眠解除方法。然后，估计基本温度。在恒温和交替温度等打破休眠的方法中，赤霉酸、H2SO4和赤霉酸+H2SO4处理，预冷和后熟，后熟是最成功的一种。凹痕和分段模型是最适合确定基数温度的模型。凹痕模型的基础温度、最佳温度和天花板温度分别估计为 0.02、18.97 至 25.32 和 27.00 °C。分段模型的这些值为 0.01、24.3 和 27.08 °C。种子在 15 和 20 °C 时表现出较高的发芽均匀性，但当温度达到 27 °C 左右时，它们进入热休眠状态。根据研究区域的温度条件，双低油菜籽播种过早会导致杂草面临高于天花板的温度。因此，概括地说，适当的播种日期可被视为在任何给定区域控制这种杂草的可行管理实践。这是关于估计切叶天竺葵基本温度的第一份报告。双低油菜籽的早期播种将导致杂草面临高于天花板的温度。因此，概括地说，适当的播种日期可被视为在任何给定区域控制这种杂草的可行管理实践。这是关于估计切叶天竺葵基本温度的第一份报告。双低油菜籽的早期播种将导致杂草面临高于天花板的温度。因此，概括地说，适当的播种日期可被视为在任何给定区域控制这种杂草的可行管理实践。这是关于估计切叶天竺葵基本温度的第一份报告。