Study On The Functional Specializing Of Two Clonal Plants In Reciprocal Patchiness Of Resources

We studied on the resource functional specializing of a native clonal plant Glechomae Longitubae and an exotic clonal plant Alternanthera philoxeroides (Mart.) Griseb when experiencing reciprocal patchiness of resources (PRP) where two resources tend not to occur together. We compared the capacity of division of labor in these two species via biomass allocation patterns, morphological and physiological plasticity of resources absorb organs. We also measured the biomass including total biomass and R/S ratio, root morphology including root length, root surf-area, root forks and root tips, and photosynthetic characteristics including chlorophyll content, net photosynthetic rate and maximum net photosynthetic rate. Further, we tested the response of ramets of A. philoxeroides to the different lighting conditions though four photosynthetic adaptation ways including specific leaf area, leaf nitrogen content, nitrogen use efficiency and nitrogen allocation in the photosynthesis under different lighting conditions. The results showed that the ramets in HL patches allocated relatively more biomass to above-ground parts than those in LH patches, also have a weaker root system and a greater photosynthetic capacity. While the ramets in LH patches allocated relatively more biomass to under-ground parts than those in HL patches, also have a greater root system and a weaker photosynthetic capacity. This suggested that these two clonal plants realized division of labor by adjusting the biomass allocation, morphological and physiological plasticity among organs of above and under ground parts. Division of labor could be reached not only by biomass allocation, but also morphological and physiological plasticity. The plastic response of clonal plants to the heterogenetic habitats is complex and various, division of labor is just one of them. Under the same heterogenetic treatment, different clonal plants adopt different ways to realize division of labor and the capacity of division of labor is also different. In our study, the capacity of division of labor in A.philoxeroides was greater than that of G.Longitubae as A. philoxeroides could capture and utilize resources more effectively. The different allocation patterns of nitrogen in photosynthesis show the adaptation of ramets to the different lighting conditions, all the indicators are closely related and interacted. The adaption of A. philoxeroides to the different lighting conditions chould be seen in the changes of specific leaf area, leaf nitrogen content, nitrogen use efficiency and nitrogen allocation in the photosynthesis, all tendencies were consistent with the photosynthetic characteristics, which showed the mechanism of lighting adaptation in A. philoxeroides.