Do proportions of rooting ramets in the clone affect the overall growth of the stoloniferous clonal plant Zoysia japonica?

It is naturally common that different proportions of ramets in a clone lose rooting conditions due to habitat stress or obstacles, which potentially affects the overall growth of the clonal plant to different extents. However, so far, little attention has been paid to such phenomena and much less to the underlying ecological mechanisms. Taking Zoysia japonica as material, through an experiment with two nutrition levels in the habitats and five rooting ramet proportions in the clones, the impacts of proportions of rooting ramets in the clone on the overall growth were tested and the ecological mechanisms were analyzed. The results showed that there was no significant difference in the total clonal biomasses among the clones with five rooting ramet proportions under high and low nutrition levels, except for that with 0% rooting ramet proportion. Under both high and low nutrition levels, the lower rooting ramet proportions (0% and 25%) in the clones significantly decreased the number of the so-called A- and B-ramets, root biomass, stolon length per unit biomass, and root–shoot ratio, but significantly increased the stolon biomass of the clones. Stolon elongation was promoted under high nutrient level, and biomass allocations to stolons and roots increased under low nutrition levels. A-ramet biomasses accounted for about 50% and 30% of the total biomasses of the whole clone under high and low nutrition levels, respectively. These results might be reasonably explained in terms of clonal integration, compensatory growth, division of labor, and bet-hedging strategy.