Seed dormancy-life form profile for 358 species from the Xishuangbanna seasonal tropical rainforest, Yunnan Province, China compared to world database.

Seed dormancy profiles are available for the major vegetation regions/types on earth. These were constructed using a composite of data from locations within each region. Furthermore, the proportion of species with nondormant (ND) seeds and the five classes of dormancy is available for each life form in each region. Using these data, we asked: will the results be the same if many species from a specific area as opposed to data compiled from many locationsare considered? Germination was tested for fresh seeds of 358 species in 95 families from the Xishuangbanna seasonal tropical rainforest (XSTRF): 177 trees, 66 shrubs, 57 vines and 58 herbs. Seeds of 12.3% of the species were ND, and 0.3, 14.8, 60.6, 12.0 and 0% of the species had morphological (MD), morphophysiological (MPD), physiological (PD), physical (PY), and combinational (PY + PD) dormancy, respectively. PD was more important than ND in all life forms, PY was highest in shrubs, MD was not important in any life form and MPD was most common for herb and vines. The seed dormancy profile for XSTRF differs considerably from the composite profile for this vegetation type worldwide, most obviously in ND being much lower and PD much higher in XSTRF.

[Research advances in population dynamics of Orchidaceae].

In the study of population dynamics of Orchidaceae, demographic analysis can make us better understand the spatiotemporal variation of plant individuals, the core of the population dynamics study. Nevertheless, many orchid species have an epiphytic or lithophytic habit, which predisposes them to a discrete or patchy distribution. In this case, metapopulation study is a good method to judge the protective scale of the population by analyzing the extent of gene flow among patches. In addition, long-term observation is needed to obtain reliable information on the life history and population dynamics of Orchidaceae, and to understand the relationships between the spatiotemporal variation and functioning of orchid population in certain environmental conditions. As for the short-term study, it's essential for a better understanding of the relationships between the structurally dependent plants and the communities in which they are fund. This paper reviewed the research advances in the population dynamics of Orchidaceae from the viewpoints of the population ecology and ecological characteristics of Orchidaceae.