昭和草（Crassocephaium crepidioides(Benth.) S. Moore)屬於菊科昭和草屬一年生草本，遍布台灣全島山野平地，原產於非洲、馬達加斯加島，今已成為全球泛熱帶地區歸化植物。為了探討昭和草在海拔分布上的差異，本研究擬比較不同海拔高度收集之種子，在不同環境因子（恆溫、變溫、水分含量多寡、鹽分濃度含量、不同光質及埋土深度）處理下對其種子發芽能力之影響。昭和草種子的發芽溫度範圍為15〜30°C，曰夜恆溫最適發芽溫度在15〜30°C之間，曰夜變溫最適發芽溫度為30/25C，以高海拔地區的種子較耐高温；昭和草種子可發芽的水分潛勢範圍在0 MPa〜-0.4 MPa之間，最適合的水分潛勢為0 MPa〜-0.2 MPa之間，以高海拔地區的種子較耐低水分潛勢；在鹽分方面當鹽分濃度0.2%以下時對其發芽率無顯著的影響，以低海拔地區的種子對鹽分較敏感；光質部分以照射紅光和白光種子發芽率最高皆達70%以上，高海拔地區的種子在不同光質照射下擁有較高的發芽率；埋土深度以埋土 0 cm的出土率最高，種子出土率隨埋土深度增加而有下降的趨勢，在埋土深度超過3 cm以上，則種子無法發芽。

Crassocephaium crepidioides (Benth.) S. Moore, native to Africa ana Madagascar, is an annual weed in Taiwan. Nowadays, C. crepidioides has become a naturalized plant in the pan-tropics area. In this study, we want to know the species distribution of C. crepidioides at different altitudes. Objective of this research was to investigate the effects of environmental factors including constant temperature, alternate temperature, osmotic potential, NaCl concentration, light quality, oxygen, and sowing depth on seed germination of the C. crepidioides collected from different altitudes in Taiwan.
Experimental results showed that the temperature range of seed germination for し. crepidioides was 15-30oC. The constant and alternate temperatures of day/night for germination were ranged from 15 to 30C and at 30/25 C, respectively. Seeds of C. crepidioides able to germinate at water potential of -0.4 to 0 MPa and the optimum water potentials ranged from -0.2 to 0 MPa. Germination of seeds collected at high altitudes have the higher tolerance to the lower water potentials. In addition, germination was not changed under the treatment of 0.0-0.2% NaCl solution. However, seeds collected from low altitude area were more susceptible to NaCl. Under the light quality treatment, germination percentage of し.crepidioides was more than 70% by either white or red light; seeds from high altitude area had higher germination percentage than that from low altitude area. Burial experiment showed that the highest percentage of germination was observed while it was burried at depth of 0 cm, and germination percentage decreased with increasing bury depth. All seeds did not germinate when sowing depth more than 3 cm.