Reproductive allocation of three Gentianaceae species

To test the tactics of resource allocation, pollinator abundance, and mating system, the reproductive allocation characters of three species of the family Gentianaceae Gentianopsis paludosa (selfing), Gentiana farreri (outcrossing with high insect visit frequencies), and Swertia przewalskii (outcrossing with low insect visit frequencies), were tested at the same habitat in the eastern Qinghai-Tibetan Plateau. The results showed that the P/O ratios differ significantly among these three species. The P/O ratio of G. paludosa was significantly lower than that of the other two cross-fertilized species, and the P/O ratio of S. przewalskii was significantly lower than that of G. farreri. Reproductive allocation differed significantly among the three species. G. paludosa had a higher reproductive allocation than that in the two cross-fertilized species, and the reproductive allocation of G. farreri was higher than that in S. przewalskii. The reproductive allocations of the two cross-fertilized species G. farreri and S. przewalskii were negatively correlated with their respective individual sizes, whereas G. paludosa did not reveal any relationship between these two parameters. The results indicated that mating system and pollinator abundance might influence resource allocation characteristics. Although the reproductive biomass of the three species was positively correlated with their individual size, the reproductive allocation of the self-fertilized species was significantly higher than that in the two cross-fertilized species. In addition, its high reproductive allocation was not affected by individual size. It appeared that the high reproductive allocation might be caused by reproductive assurance, which in turn might reduce the reproductive cost in the self-fertilized species.