Main content area

Disappearing rhizosphere effect of shaded ramet re-occurs through support of carbon assimilates from unshaded one in a clonal fragment

Li, Yang, Chen, Jin-song, Xue, Ge, Song, Hui-xing, Liu, Chun-hua
Rhizosphere 2019 v.11 pp. 100166
Phyllostachys, ammonium, carbon, clones, dissolved organic nitrogen, enzyme activity, extracellular enzymes, microbial nitrogen, nitrate nitrogen, nitrification, nutrients, photosynthates, progeny, rhizodeposition, rhizomes, rhizosphere, root exudates, roots, shade, soil
Carbon or nitrogen availability in the rhizosphere is strongly affected by plant roots rhizodeposition and nutrients uptake. The study focused on the coupling of rhizosphere effect on microbial processes and changes in belowground carbon input caused by clonal integration. Sufficient clonal fragments of Phyllostachys bissetii were selected in-situ, consisting of a mother ramet and an offspring ramet. Shading treatment was performed for the offspring ramets. Rhizomes between two ramets were connected or severed. Carbon and nitrogen availabilities were assessed in the rhizosphere or bulk soil of shaded ramets, as well as nitrogen turnover and extracellular enzyme activities. The results showed that clonal integration increased the DOC level, microbial biomass nitrogen, enzymes activities and nitrogen nitrification rate in the rhizosphere of shaded ramet. Available nitrogen (dissolved organic nitrogen, ammonium or nitrate nitrogen) was decreased by rhizome connection. Significant effect of location and rhizome connection status and their interaction were observed. Shading treatment of severed ramet reducing the photosynthates flow to the soil led to similar rhizosphere process compared to bulk soil. Further, the disappearing rhizosphere effect on microbial processes of shaded ramet re-occurred due to the support of photosynthates translocated from unshaded one in a clonal fragment. The results suggest that recovered root exudates in the rhizosphere of shaded ramet by clonal integration stimulated a better adaption of clonal plant under heterogeneous light habitats.