title: Reproductive biology and variation of nuclear ribosomal ITS and ETS sequences in theCalligonum mongolicumcomplex (Polygonaceae).
abstract: To explore the biosystematics of theCalligonum mongolicumcomplex (Polygonaceae), the flowering phenological period, breeding and pollination characters and seed set of the complex (Calligonum MongolicumTurze,Calligonum chinenseA. Los.,Calligonum gobicumA. Los.,Calligonum pumilumA. Los. andCalligonum zaidamenseA. Los.) were documented in the Turpan Eremophyte Botanical Garden, China. The sequences of the nuclear ribosomal ITS and ETS region were employed to differentiate theCalligonum mongolicumcomplex and other species in sect. Medusae. The results showed species of theCalligonum mongolicumcomplex occupied overlapping flowering periods and had consistent pollination agents. Their breeding systems are all self-compatible, tend to be out-crossing and they interbreed amongst each other (out-crossing index, OCI = 4).The crosses within and amongst species had high seed sets (44 - 65%). Phylogenetic analyses of Calligonum sect. Medusae and the network analysis of nrDNA (ITS and ETS) in the complex suggest interbreeding amongst "species" within the complex and provide evidence for taxonomically merging the five species in the complex. The detected hybridisation, occurring within the complex, suggests the need to improve traditional methods ofex situplant conservation in botanical gardens for maintaining genetic diversity ofCalligonumwithin and amongst species from different geographic areas.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Turpan Eremophytes Botanic Garden, Chinese Academy of Sciences, Turpan 838008, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.affiliation: Department of Botany, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Wen
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Turpan Eremophytes Botanic Garden, Chinese Academy of Sciences, Turpan 838008, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Botany, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Johnson
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Turpan Eremophytes Botanic Garden, Chinese Academy of Sciences, Turpan 838008, China.
authors.forename: Borong
authors.initials: B
authors.lastname: Pan
keywords: Breeding System; Calligonum mongolicum complex; Crossing experiments; ETS; ITS; Phenology; Phylogeny