Abstract: By the methods of field observation and artificial pollination, this paper studied the characteristics of pollination biology and breeding system of endangered species Craigia yunnanensis in the fragmented habitats of Fadou distribution area, Xichou County of Yunnan Province, Southwest China. Each cyme of the C. yunnanensis had 2-9 hermaphroditic flowers, and the lifespan of a single hermaphroditic flower was approximately 3-4 days. There existed certain temporal isolation (dichogamy) and spatial isolation (herkogamy) between the pistils and stamens of each hermaphroditic flower. The outcrossing index (OCI) was >4, and the ratio of pollen to ovule (P/O) was 1381±53. The most frequent and effective pollinator was Chrysomyia megacephala. The fruiting rate of geitonogamous pollination was rather low, and thus, the breeding system of C. yunnanensis was mainly belonged to outcrossing, with partial selfcompatibility, and the pollinator insects were essential. Both the fruit-setting ratio and the seed-bearing ratio under natural conditions were low as 56.67%±3.85% and 6.26%±0.75%, respectively, whereas artificial xenogamous pollination could significantly promote the fruit-setting and seed-bearing ratios (P< 0.01). In the fragmented habitats, the pollinators were lesser, and the pollination efficiency was lower, suggesting that habitat fragmentation affected the early stage reproduction process of C. yunnanensis plants.

Key words: forestry remote sensing, spectral mixture analysis, sequential Gaussian co-simulation, forest carbon density, Hunan Province.