Chromosome numbers and karyotypes of 18 species of Epimedium sect. Diphyllon (Berberidaceae) from central China

ABSTRACT

Epimedium is the largest and one of the most important herbaceous genera in Berberidiaceae, especially for section Diphyllon, which has a diversification center in central China. Chromosome numbers and karyomorphology of 24 accessions were examined, representing 18 Epimedium species, five of which were counted here for the first time. A chromosome number of 2n = 2x = 12 was observed for all taxa and all karyotypes were Stebbins’ 2A, except for E. acuminatum, E. brevicornu, E. ilicifolium and one accession of E. leptorrhizum, which were 3A. Their asymmetry index (AI) values vary from 1.71 to 4.56. Intercalary satellites are commonly found on the first or second pair. More than two individuals were sampled for E. franchetii, E. leptorrhizum, E. stellulatum, and E. wushanense and all had consistent and stable cytological traits with respect to their karyotype formula, Stebbins’ asymmetry, and AI values, except for E. leptorrhizum. The significance and limits of the cytological results for Epimedium are also briefly discussed.

KEYWORDS:

• Berberidaceae
• chromosome number
• karyotypes
• Epimedium sect. Diphyllon

Acknowledgments

We thank Min Gao, Li-Ying Luo, and Zhen-Xin Xie for assistance in cytological lab works and Meng-Hua Zhang for her valuable comments on the early version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by grants from the Nature Sciences Foundation of China [31560060, 31570211], the educational reform project of Jishou University [2016SYJG014, 2016KCB13, JG2017B01], the National Special Fund on Basic Research of Science and Technology of China [2014FY110100], Traditional Chinese Medicine Public Health Special Project [[2011]76, 201207002], Heavy Metal Pollution Control and Ecological Restoration in Xiangxi Mining for Graduate Training Innovation Base of Hunan Province, and Jishou University Undergraduate Research Innovation Project [JDX17023].