The clonal phenotypic variation and reproductive strategies of Kobresia setchwanensis along altitude in Northern Tibet

The phenotypic and reproductive characteristics of Kobresia setchwanensis were investigated and analyzed in order to understand the clonal phenotypic variation and reproductive strategies of this species along altitude in Northern Tibet. For the clonal phenotypic parameters, there were significant differences among populations from different altitudes. The most suitable altitude for K. setchwanensis was about 4400m above sea level in Northern Tibet. With the increase of the altitudes, the plant height, ramet number and biomass accumulation of K. setchwanensis decreased. The number of reproductive branches and grains per spike, the germination rate and biomass allocation also decreased with the increase of altitude which suggested that there was a trade-off relationship between the sexual reproduction and the clonal reproduction of K. setchwanensis. The results suggested that K. setchwanensis gradually reduced input of the sexual reproduction while increased input of the clonal reproduction to maintain and expand the population with the increase of the altitude.