Artemisiaqingheensis (Asteraceae, Anthemideae), a new species from Xinjiang, China.

Artemisiaqingheensis (Asteraceae, Anthemideae), a new species from Qinghe County, Xinjiang, China, is described and illustrated. We investigated its phylogenetic position and relationships with 35 other species of Artemisia using whole chloroplast DNA sequence data. The molecular phylogenetic results and morphological evidence (multi-layered involucral bracts and homogamous capitula with bisexual flowers) showed that the new species belongs to ArtemisiasubgenusSeriphidium. A diagnostic table and discussion of morphological characters are provided to distinguish the new species from A.amoena, A.gracilescens, A.lessingiana and A.terrae-albae.

The complete chloroplast genome of an endangered plant Artemisia borotalensis (Asteraceae) and phylogenetic analysis.

Artemisia borotalensis Poljakov is an endemic and endangered herb in China. In this study, we sequenced and analyzed the complete chloroplast genome of this species. Sequencing revealed the genome to be 151,179 bp in length, containing a large single copy region (82,862 bp), a small single copy region (18,377 bp), and a pair of inverted repeat regions (24,970 bp each). Our analyses demonstrated that it contained 133 genes, including 87 protein-coding genes, 37 transfer RNA genes, eight ribosomal RNA genes, and one pseudogene (ycf1). Furthermore, we found the genome to have an overall GC content of 37.4%. A phylogenetic analysis indicated that A. borotalensis and A. maritima clustered together as sister group to A. annua and A. fukudo clade.

Chemical composition and phytotoxic activity of the essential oil of Artemisia sieversiana growing in Xinjiang, China.

The chemical profile and phytotoxic activity of the essential oil extracted from Artemisia sieversiana was investigated. In total 17 compounds were identified by GC/MS, representing 99.17% of the entire oil, among which α-thujone (64.46%) and eucalyptol (10.15%) were the most abundant constituents. The major components, their mixture as well as the essential oil exhibited significant phytotoxic activity against Amaranthus retroflexus, Medicago sativa, Poa annua and Pennisetum alopecuroides, with their IC50 values ranged from 1.55 ∼ 6.21 mg/mL (α-thujone), 1.42 ∼ 17.81 mg/mL (eucalyptol), 0.23 ∼ 1.05 mg/mL (the mixture), and 1.89 ∼ 4.69 mg/mL (the essential oil) on the four tested species. The mixture of the major constituents exerted more potent effect compared with each individual compound, indicating the possible involvement of synergistic effect of these two compounds.