Comparative reproductive biology of Apocynum venetum L. in wild and managed populations in the arid region of NW China

摘要

Apocynum venetum L. (dogbane) is one of the ecologically important species in the arid region of Northwest China. To select plants with higher flowering rate and fruit production, we investigated the following characteristics of A. venetum in wild and managed populations: flowering dynamics, pollen viability, pollen limitation, floral visitors and breeding system. We found that the species showed four reproductive characteristics. First, the flower production period and flowering peak were different between the wild and managed populations, longer in the managed. Second, A. venetum was pollen-limited, and pollen limitation was more intense in the wild population than in the managed. Third, in the wild, Apis mellifera L. was found to be frequent pollinator, Ophion luteus L. being the most frequent and effective visitor in the managed. Finally, the pollen ovule rate was 36.2. Self-pollination was dominant and played an important role to assure production in the breeding system. Differences in flower production influenced by artificial selection and pollinator type explain different fruit production in managed and wild populations, further, proper management could promote re-vegetation or restoration of degraded A. venetum in this region.