Impacts Of Variation Of Light Intensity And Pattern In Homogeneous And Heterogeneous Habitats On The Clonal Growth And Morphological Plasticity Characteristics Of Zoysia Japonica

Growth characteristics and phenotypic plasticity of clonal plant reflects its adaptability to changing environmental conditions. Zoysia japonica was studied in four types of homogeneous light intensity levels, i.e., full light,30%,50%and70%shading, and9types of heterogeneous light intensity pattern, trying to reveal the effects of light intensity variation on the clonal growth and the morphological characteristics of Zoysia japonica at different developmental stages. The results showed that:(1) Zoysia japonica grew best in70%homogeneous full light condition and the total biomass and ramet number reached maximum. The sequence of general performance of Z. japonica were70%>100%>50%>30%homogeneous full light condition;(2) when Z. japonica grew in heterogeneous light conditions, the positions of30%shading belt in the habitats did not significantly affect the clonal growth and the morphological characteristics; when50%shading belt was at basal part of Z. japonica, R/S increased but the number of B-ramet decreased, moreover, other indexes were not significantly affected, compared with the conditions of50%shading belt was at middle and distal parts; when70%shading belt was at basal part of Z. japonica, R/S increased but other indexes decreased, compared with the conditions of70%shading belt was at middle and distal parts. When the shading belts with different intensities were at middle and distal parts, all indexes were not affected significantly. These characteristics might be explained in the theories of ecological adaption, specialization in abundance and division of labor.(3) Z. japonica improved the performance in heterogeneous environment due to the effects of physiological integration. Biomass and ramet number of the clonal fragments significantly increased in different habitats with the same position of patch or pseudo-patch, due to the effects of clonal integration between different parts of the clones. However, the adverse effects of serious shortage of light in the habitats could not remedied by the role of clonal integration. In this case, Z. japonica increased root to shoot ratio and reduced the number of ramets B. The role of clonal integration in improving the clonal growth in basal patch was limited, due to the distal dominance of directionality of physiological integration. This research might help to understand the growth and developmental characteristics and adaptive strategies of Zoysia japonica under different light conditions, and theoretically and practically guide the scientific management of Zoysia grassland.