Effects of different spatial distributions on growth pattern of Chenopodium aristatum

On degraded Inner Mongolia grassland, Chenopodium aristatum was companion species and normally aggregated. In order to explore whether natural spatial distribution type formed after long term evolution affect the existence of C. aristatum, this paper studied the growth pattern of C. aristatum population under regular, aggregate and random spatial distributions. Results showed that the spatial distribution type significantly affected height of individuals, aboveground biomass, belowground biomass and total biomass of C. aristatum population. Height of individuals was the tallest under regular distribution and significant taller than those under both aggregate and random distributions. At the same time, there was no significant difference under aggregate and random distributions. However, biomass indices (aboveground biomass, belowground biomass and total biomass) under aggregate and random distribution were significantly larger than those under regular distribution, but there was no significant difference between biomass indices under aggregate and random distribution. The individual height of C. aristatum aggregate distribution did not show a significant advantage over regular and random distributions, while the three biomass indices of aggregate distribution showed significant advantage over regular distribution but not random distribution. The advantage of aggregate distribution formed after long term evolution was put up only on some indices of growth pattern. The reason was that interspecific interactions and exotic disturbances were excluded artificially under the controlled experiment.