The reproductive biology of Calligonum L. in relation to ex situ conservation in a botanical garden

In this study, we observed the flowering phenology, breeding system, pollination and seed germination of four species of Calligonum (C. calliphysa, C. rubicundum, C. densum and C. ebinuricum) in the Turpan Eremophytes Botanic Garden, China. Our results showed that the species had overlapping flowering phenologies and were pollinated by similar pollination agents. Their breeding systems were self-compatible, and with signs of outbreeding, but not of hybridization with each other; the main isolation mechanism was post-zygotic isolation and they also had high seed germination rates. Therefore, they are suited to ex situ conservation in the Turpan Eremophytes Botanic Garden, and can supply sufficient seeds for renewal populations and the conservation of germplasm resources. Furthermore, these results provide theoretical support for the construction of a national germplasm resource garden of Calligonum, and for the introduction to the garden of other eremophyteplants and their conservation.