紅毛草(Rhynchelytrum repens)種子休眠解除之

探討

侯金日 吳崇僑

國立嘉義大學農藝學系

摘 要

本研究主要目的在探討不同之休眠解除方式對紅毛草種子發芽之影響，初期採收之紅毛草種子具有很強之休眠性，故進行各種不同處理（冷層積處理、冷凍法處理、淋洗法處理、GA₃處理和濃硫酸處理）對紅毛草種子休眠解除之影響，試驗結果如下：

冷層積處理而言，處理時間越久（8週），發芽率愈高、處理期間溫度愈低（5℃）發芽率愈高，而且以5℃冷層積處理8週發芽率達78%；發芽速率亦以5℃冷層積處理8週最高。

冷凍法處理可有效解除紅毛草種子休眠，經過冷凍處理後的種子發芽率明顯較未經冷凍處理的種子為高，冷凍處理以冷凍3天在20/15℃下所進行之發芽試驗效果最佳；發芽速率亦有相同之現象。

淋洗法處理亦顯著提高紅毛草種子之發芽率及發芽速率，經過2天淋洗處理的種子，其發芽率及發芽速率顯著較淋洗1天及未淋洗者為高。

濃硫酸處理和GA₃處理有部分提高紅毛草種子之發芽率與發芽速率。濃硫酸處理以100%的濃度效果最佳，但發芽率只有41%；而GA₃處理以0.3%最佳，但發芽率亦只有34%。發芽速率在兩種藥劑處理中，亦以100%的濃硫酸濃度及0.3%之GA₃處理最佳。

關鍵詞：紅毛草、種子發芽、休眠解除、冷層積處理、冷凍處理、淋洗處理、GA₃處理、濃硫酸處理、化學藥劑

Studies on the Dormancy Breaking of Rhynchelytrum repens Seeds

Chin-Jin Hou Chung-Chaun Wu

Department of Agronomy, National Chiayi University, Taiwan, R. O. C

Abstract

The purpose of this research was to study the effects of dormancy breaking on the germination of Rhynchelytrum repens seeds. The freshly harverted seed of Rhynchelytrum repens seeds showed a strong dormancy. Different dormancy breaking treatments, including stratification, freezing, leaching, gibberellic acid (GA₃) and scarification, were thus conducted. The results were summarized as follows:

The treatment of stratification at 5℃for 8 weeks showed highest germination (78%) and germination rate index(GRI). Highter temperature and /or shooter duration of the treatment showed less effect.

The freezing treatments were effective in breaking the seed dormancy of Rhynchelytrum repens. The germination percentage of those seeds under freezing treatments were significantly increased than those without treatments. The seeds under 3-day freezing treatments showed highest germination rate in the 20/15⁰C growth chamber. So was the GRI under the same condition.

The leaching treatments also significantly increased the germination percentage and the GRI of the Rhynchelytrum repens seeds. The germination percentage and the GRI for those seeds under 2-day leaching were higher than those under the treatment of 1-day leaching.

The sulfuric acid and gibberellic acid (GA₃) treatments showed partially effectiveness in increasing the germination percentage and the GRI of the Rhynchelytrum repens seeds.The optimum concentration was 100% for sulfuric acid and 0.5% for GA₃ which raised percentage germination of this grass seeds to 41% and 34%, respectively.

Key words：Rhynchelytrum repens , seed germination, dormancy breaking, stratification treatments, freezing treatments, leaching treatments, gibberellic acid (GA₃), sulfuric acid treatments, chemical medicament.