In-situ and ex situ pollination biology of the four threatened plant species and the significance for conservation

Both in situ and ex situ conservation are important strategies for protecting threatened plant species. Nevertheless, the success of conservation depends on whether the plant species can naturally regenerate and accomplish its life cycle over a long-term. Here we studied the pollination biology of the threatened species Hibiscus aridicola, Amorphophallus albus, Stemona parviflora and S. japonica aiming to get data about pollination strategies, pollinators as well as mating systems. These experiments were performed at Kunming Botanical Garden (KBG) for ex situ and the plant species' natural habitat for in situ conservation. The results indicated that H. aridicola is self-compatible and had pollinators under both ex situ and in situ conditions. The other three species are all self-incompatible and a limited number of pollinators for S. parviflora and S. japonica were observed at cultivated and natural habitats. Amorphophallus albus had no pollinators at KBG but a large number of rove beetles (Atheta sp.) could be observed in the plant species' natural habitat. This resulted in a high fruit set under natural conditions (73.3%, n = 30). The results showed clearly, that appropriate pollinators for the four plant species are not present all the time and all localities, which further influences the reproduction success of a plant species. Hence, for a successful conservation, it is vital to assess the species reproduction strategy prior deciding whether in situ and/or ex situ conservation should be carried out.