This study aimed to investigate the effects of altitude and aspect on the essential efficiency and the phytochemical properties of Artemisia aucheri and Artemisia sieberi in mountainous and Steppe rangelands of South Khorasan Province. Experiment was conducted in a completely randomized design (CRD) with two treatments of altitude in four levels (<1800, 2000-1800, 2200-2000, and > 2200 meters above sea level) for Artemisia aucheri and in three levels (1400, 1600, and 1800 m above sea level) for Artemisia sieberi and aspect in four levels (north, south, east and west) for Artemisia aucheri with three replications. Aboveground samples were collected in the flowering stage and their essential oils were extracted using the Hydrodistilation method. Phytochemical properties of the samples such as the amount of total phenol, total flavonoid, antioxidant activity, and total tannin were determined using the Spectrophotometer. The results showed that altitude had a significant negative and positive effects on the essential efficiency of Artemisia aucheri and Artemisia sieberi respectively (p ≤ 0.01). The results of Pearson's correlation coefficient showed that there was a significant correlation between altitude and essential efficiency and total phenol content of Artemisia aucheri (-0.94 and +0.66, respectively), as well as essential efficiency, total phenol and total tannin of Artemisia sieberi (+0.81, +0.68 and -0.86, respectively). The highest essential efficiency of Artemisia aucheri was observed in the eastern aspect (2.63%) and the lowest essential efficiency was detected in the southern aspect (1.28%). This study indicated that collecting the aerial parts of this species at low altitudes will yield a high percentage of the essential efficiency.
 

Keywords: Physiographic factors, Essential efficiency, Phenolic compounds, Tannin, Artemisia.

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