ABSTRACT In vitro germination tests were performed at 11 constant temperatures (range 2.5–35°C) to quantify the maximum germination percentage and germination rate of four subterranean clover cultivars (‘Antas’, ‘Denmark’, ‘Monti’ and ‘Narrikup’). These were used to estimate their cardinal temperatures, base (Tb ), optimum (T opt) and maximum (Tmax) and the thermal time requirements for seed germination. Germination percentages were ≥ 88% in the 5–25°C temperature range for all cultivars. The time to reach 50% of final germination (T 50) decreased from 12 to 2 days as the temperature increased from 2.5 to 17.5°C. The determined T opt were 16°C for ‘Monti’ and ‘Narrikup’ and 22°C for ‘Antas’ and ‘Denmark’. At a common Tb of 0°C the thermal time requirements for T 50 were 32 ± 1°Cd for ‘Antas’ and ‘Denmark’ and 39 ± 1°Cd for ‘Narrikup’ and ‘Monti’. ‘Antas’ and ‘Denmark’ (both from Italy) germinated at the widest range of temperatures.

中文翻译：

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四种地下三叶草品种发芽的热时间要求

摘要 在 11 个恒温条件下（范围 2.5-35°C）进行体外发芽试验，以量化四种地下三叶草品种（'Antas'、'Denmark'、'Monti' 和 'Narrikup'）的最大发芽率和发芽率. 这些用于估计它们的基本温度、基础温度 (Tb)、最佳温度 (T opt) 和最大值 (Tmax) 以及种子发芽所需的热时间。在 5-25°C 的温度范围内，所有品种的发芽率≥ 88%。随着温度从 2.5°C 增加到 17.5°C，达到最终发芽 (T 50) 50% 的时间从 12 天减少到 2 天。“Monti”和“Narrikup”的确定 T opt 为 16°C，“Antas”和“Denmark”的确定 T opt 为 22°C。在 0°C 的常见 Tb 下，“Antas”和“丹麦”对 T 50 的热时间要求为 32 ± 1°Cd，“Narrikup”和“Monti”为 39 ± 1°Cd。