本研究目的在探討環境因子恆溫、變溫、鹽分濃度、滲透壓、光質、酸鹼值對紫花苜 蓿sarira L.)的兩品系一中東苜蓿（Middle East )及台灣栽培種苜蓿Hunter River種子發芽特性之影響。結果顯示：Middle East在25°C時有最髙發芽率，之後隨著溫 度升髙，其發芽率開始下降，至45°C時發芽率只有2.67%，Hunter River在10°C〜40°C時 發芽率都較Middle East髙，但至45°C處理下，Hunter River完全不發芽，而兩苜蓿種子皆 在25°C時發芽速率指數最髙。Middle East在變溫25/20°C、Hunter River在30/25°C時有最 髙的發芽率、最佳的發芽速率指數。在鹽分濃度方面，Middle East於NaCl 0〜2%間、 Hunter River於0〜0.8%間，種子皆有發芽能力，因此Hunter River種子對鹽分較為敏感， 而在鹽分濃度0%時，兩苜蓿有最髙的發芽率、最短的平均發芽日數、最佳的發芽速率指 數。此外，Middle East種子的耐旱表現較亦佳，其可發芽的水分潛勢範圍在0〜-0.4 Mpa、 Hunter River種子則在0〜-0.2 Mpa，其中，於水分潛勢0 Mpa時，Middle East與Hunter River的發芽率最髙、平均發芽日數最短、發芽速率指數最髙。白光與紅光能促進Middle East、Hunter River種子發芽，在白光處理下，Middle East的發芽率最髙達78.67%，且平 均發芽日數最短、發芽速率指數最佳；Hunter River在白光及紅光處理下有相同的髙發芽率 82%，但在紅光處理下，Hunter River的平均發芽日數最短，因此其在紅光處理下發芽速率 指數最佳，然而遠紅光及黑暗環境會抑制種子發芽。溶液酸鹼度方面，在pH 4〜10間 MiddleEast種子可發芽，但HunterRiver種子僅在pH6〜9處理下有較髙的發芽率，而兩苜 蓿皆在pH 7處理下的發芽能力較佳，但仍以控制組純水的發芽率最髙、平均發芽日數最短、 發芽速率指數最髙。

The purpose of this study is to determine the effect of various environment factors, such as constant temperatures, alternate temperatures, salt stress, osmotic pressure, light quality and pH value on alfalfa (Medicago sativa L. ) seeds germination. Alfalfa cultivars Middle East and Hunter River was used in this study. The results showed : As the temperature increased to 35〇C, the germination percentage of both alfalfa began to decrease significantly. At 45 ° C, the germination percentage of Middle East was only 2.6% and the Hunter River did not germinate at all. Middle East and Hunter River had the best germination percentage at 25/20 °C and 30/25 °C, respectively. Alfalfa seeds at alternate temperatures had better germination percentage than at constant temperatures. Seeds of Middle East were able to germinate in the water containing 0-2% salt. In contrast, germination of Hunter River seeds was restricted to 0-0.8% salt. Therefore, Middle East seeds are more salt-tolerant. In addition, Middle East seeds also showed good drought tolerance, with it could germinate range from osmotic potentials 0 to -0.4 Mpa and Hunter River seeds germinate range from 0 to -0.2 Mpa. White and red light promoted both alfalfa seeds germinate. Under white light treatment, the germination percentage of Middle East is up to 78.67%. Hunter River had the same high germination percentage of 82% under white and red light treatment. However, the dark environment would reduce alfalfa seeds germination percentage. Middle East seeds germinate at pH 4〜10, but Hunter River seeds only have higher germination percentage at pH 6 〜9. Under the pH 7 treatment, the germination percentage of both alfalfa were better, but it were still lower than the control treatment, which was using water (pH 6.8).