The Effects Of Two Nutrition Levels And The Proportion And Arrangement Patterns Of Rooting Ramets To The Clonal Growth Of Zoysia Japonica

Clonal ramets usually can get the required nutrient resources directly through the soil by means of their own roots, and also can get the nutrients with the help of clonal integration. However, in natural habitats, ramets are not always able to get the resources directly from soil, since every ramets do not always possess the rooting conditions, resulting in the acquisition of soil resource often have to rely on the rooting ramets with different proportions within the clone, bases on which, this research focused on the ecological questions that how the different proportions and arrangement patterns of rooting ramets within the clonal plant affect the clonal growth. This research might from one side reveal the ecological strategies and mechanisms of clonal plants growing in the complex habitats.The typical clonal plant Zoysia japonica was selected as the object of this study. By maniplating the experiment precisely, the impacts of 5 types of proportions of rooting ramets within the clone in the habitats with high and low nutrition levels respectively, on the clonal growth of Zoysia japonica were studied, and the possible mechanisms were tried to analyze.The main results were as follows:1. The differences in the rooting proportions of clonal plant ramets had different impacts on clonal growth of Zoysia japonica at two different nutrient (low/high) habitats. In the high nutrient habitat, the biomass of clonal plant was significantly affected by the changes in ramets rooting proportion. The biomass of 0% ramets rooting proportion was minimum in all 5 ramets rooting proportions, and significantly different with in all treatments. The biomass of 50% ramets rooting proportion was the highest, but it had no significant difference with other treatments. In low nutrient habitat, the biomass of clonal plant was not significantly affected by the changes in ramets rooting proportion, and the biomass between the treatments was very similar. The changes in ramets rooting proportion significantly affected the biomass of clonal plant roots no matter under what nutrient levels. The 0% ramets rooting proportion treatment was significantly lower the clonal plant root biomass and had the lowest root biomass in all treatments. At 75% ramets rooting proportion, we found the biomass of Zoysia japonica root was significantly higher compared with the root biomass of 0% and 25% ramets rooting proportion, and also the biomass of root was the maximum. At the same ramets rooting proportion, Zoysia japonica had higher total biomass in the high nutrient habitat, especially in the 25%、50%、75% and 100% ramets rooting proportion. The biomass of roots was also higher in the high nutrient habitat, but had no significant difference with the low nutrient habitat.2. The stolon biomass of clonal plant at high nutrient levels was significantly affected by the changes in ramets rooting proportion. The stolon biomass of Zoysia japonica at 0% and 25% ramets rooting proportions was significantly higher than other ramets rooting proportions, but these two ramets rooting proportion had no significant difference. Only 0% ramets rooting proportion of the clonal plant significantly increased the stolon biomass of Zoysia japonica in low nutrient habitat. Zoysia japonica in the high nutrient habitat had higher stolon biomass compared with low nutrient habitat, but only at 25% ramets rooting proportion stolon biomass was significantly higher than low nutrient habitat.25% ramets rooting proportion treatment had significantly increased the length of Zoysia japonica stolon compared with 0%、50% and 100% ramets rooting proportions in high nutrient habitat, the stolon length between other treatments had no significant differences. At low nutrient habitat, the stolon length between all ramets rooting proportions had no significant differences, Zoysia japonica in the high nutrient habitat had higher stolon length than the low nutrient habitat, but only the length of stolon of 0%、25% and 75% ramets rooting proportions were significantly longer than in low nutrient habitat.3.For the 50% ramets rooting proportion, when the clonal plant ramets root in the small and even patch arrangement, Zoysia japonica had larger ramets A biomass, root biomass and total biomass in the high nutrient habitat, but had no significant difference compared with the big and even patch arrangement on the same indexes and was significantly larger than in the not even patch arrangement pattern on the same indexes. The stolon biomass was highest when the clonal plant rooting ramets were on the small and even patch arrangement pattern and the stolon biomass of the three arrangement patterns of rooting ramets had significant difference. The clonal plant which the rooting ramets were on the small and even patch arrangement pattern had the longest stolon, and significant longer than the length of clonal plant on the big and even patch arrangement pattern, but had no significant difference compared with the uneven arrangement pattern of rooting ramets. Rooting ramets on the small and even patch arrangement pattern were beneficial to the clonal growth; in low nutrient habitat, the changes in rooting ramets on different arrangement patterns had no significant impacts on the ramets A biomass and total biomass, Zoysia japonica had significant larger root biomass and stolon biomass on the not even patch arrangement pattern and the stolon length was also significant longer than on the big and even patch arrangement pattern.4. The growth strategy of Zoysia japonica was significantly affected by the changes in ramets rooting proportions. Regardless of habitat nutrition levels, the lower ramets rooting proportions of Zoysia japonica (0% and 25%) had smaller R/S ratio and significantly increased the stolon biomass distribution; with 50% ramets rooting proportion, no matter what the arrangement patterns of rooting ramets was, Zoysia japonica increased the stolon biomass distribution in low-nutrient habitat and had larger R/S ratio. On the other hand, Zoysia japonica increased the aboveground biomass distribution in high-nutrient habitat and had smaller R/S ratio. These two growth strategies fully reflected the strong plasticity and the complex ecological adaptability of Zoysia japonica when facing the adverse environmental conditions.