為探討狼尾草不同節位分蘗芽中內生植物荷爾蒙在不同季節之變化，乃利用狼尾草7262及7301兩品系，種植於國立台灣大學農業試驗場中，1986年10月至1989年6月約三年，取其中一年即1987年7月至1988年6月，每月之15日，砍下5枝，分別取下分蘗芽，分析其中之內生植物荷爾蒙含量，以春、夏、秋、冬四季加以統計分析，結果IAA夏季量最高，春秋次之，冬季含量巨減。且下部位含量較低，愈上部位，含量愈高，而兩品系均在1-10 μg/g.fw之間。Zeation含量變化趨勢亦同，但變化不如IAA者大，均呈現夏天多，春秋次之，而冬季最少；且下節位上之芽中含量較上節位芽中者少。其含量變化GA3於品系7262在20-550ng/g.fw，品系7301在10-300ng/g.fw之間。ABA含量兩品系均在5-90ng/g.fw之間變化。而由Zentin/IAA之比例，顯示在冬季兩品系均大於1，而春夏秋三季均小於1。綜合而言，各內生植物荷爾蒙，在冬季低溫下，含量均低，而在夏季高溫下，含量較高；而下部節位含量均較上部節位者為低；可能是因為低溫下及老化之組織中酵素活性較低之故。

Endegenous plant hormons are believed to regulate the growth and development of lants, and to be changed by encironmental factors.In this work, napiergrass strain 7262 and 7301 were planted at the experi mental field of Taipei, from October, 1986 to June, 1989. Duriny July,1987 to June,1988,the grasses were harvested once a month, and the tiller buds werr taken for endogenous plant hormons analysis. The dadas were seperated by 4 seasons: spring, summer, fall and winter. The results showed that IAA contents in the tiller buds were 1~10 ug/g.fw, and were the highest in summer, and the lowest in winter, and the contents were highter in the upper position than in the lower osition. Zeatin conent wa the same as IAA. GA3 contents in the tiller buds of strain 7262 were 20~550 ng/g.fw, in strain 7301 10~300 ng/g.fw. ABA contents in these two strains tiller buds were 5~90 ng/gfw. Zeatin/IAA ratio showed that it was larger than 1 in winter, but smaller than 1 in other seasons.