本文旨在瞭解香附子(Cyperus rotundus L.)及稗草(Echinochloa crus-galli Beauv.)萃取液之相剋效應(allelopathic potential)對玉米(Zea mays L. cv. Tainung l)種子發芽之影響，並比較不同溫度所產生之效應。結果顯示，該兩種雜草萃取液對玉米種子發芽均具有抑制現象，而其影響程度端視萃取液製備方法而定。萃取液於30℃下經7天發酵後製備者(30℃/7天)，抑制表現最強，依序為30℃/1天，2℃/7天，及2℃/1天者。萃取液若未經高溫高壓消毒(120℃，1.1kg/cm2，蒸氣消毒15分鐘)，將引起真菌感染而進一步降低發芽率。處理溫度介於15℃至40℃之間時，提高溫度起初將促進玉米種子發芽直至27.5℃，超此溫度發率將下降。當溫度升至35℃以上時，發芽率則劇減。綜此結果，本試驗推測在田間環境下，香附子及稗草殘株的自然分解，可能產生抑制玉米發芽之毒害物質。此一現象在土壤溫度超過27.5℃時，將愈顯嚴重，而稗草較香附子具有強相剋效應表現。

Aqueous extracts from field-grown mature plants 0 1' purplenutsedge and barnyardgrass were employed to study their allelopathicpotential on corn (Zea mays L. 的. Tainung 1) germination.Such effects in response to temperature gradientwere also investigated. The results confirmed the existence ofallelopathic potential on corn germination in both extracts atconcentration of 1 g ground powderj10 ml double distilled water.It was shown that the methods of extract preparationhad differential influences. Extracts prepared at 30 C for 7days (30 Cj7 d) obtained the strongest inhibitive effect followedby those prepared at 30 Cj1 d 2 Cj7 d and 2 Cj1 d. Fungalinfection was observed in the extracts without sterilization,which caused the further inhibition of corn germination. In therange of 15 to 40 C, increasing temperature may first stimulategermination percentage, then reduce it after 27.5 C with adramatic reduction at 35 C. The reults proposed that certainunidentified substances from the breakdown of plant residues ofpurple nutsedge and barnyardgrass, both arise from the decayof residues and the interaction of decaying weeds with soil mi-crobes, may affect seed germination of corn under natura1 conditions.Higher temperatures (above 27.5 C) will deterioratesuch phenomenon. Barnyardgrass was found more suppressiveto corn seed germination than purp1e nutsedge.