Effects of simulated warming and decomposition interface on the litter decomposition rate of Zizania latifolia and its phyllospheric microbial community structure and function
Aims Litters of emergent plants are important components of material cycling in wetland ecosystems. To clarify the effects of climate warming and habitat difference on the litter decomposition processes and phyllospheric microorganisms of wetland emergent plants is of great significance for revealing the key material cycling processes in wetland ecosystems. Methods Zizania latifolia, a dominant emergent plant in typical wetlands of Northwestern Yunnan Plateau, was chosen for this study. Using litter bag methods, we studied mass remaining and the abundance, community structure and metabolic potential of phyllospheric microorganisms of the litter from Zizania latifolia under simulated warming (1.5-2.0 ℃) and under three habitats (air, water and soil interface). Important findings Simulated climatic warming and habitat difference significantly affected the litter decomposition rate. After one-year decomposition, the mass remaining of litter was 66.4% under the simulated warming treatment, while 77.7% under the control treatment. The decomposition constant (k) value was 1.64 times under warming compared to the control. The mass remaining of litter at the water and soil interface was 42.2% and 25.3%, and the k value at the water and soil interface was 3.63 and 5.25 times of that at the air interface respectively. These results indicate that habitat difference was the key factor controlling the decomposition of emergent plant litter in wetlands. Moreover, warming mainly changed the community composition of litter phyllospheric microorganisms, while decomposition interface mainly affected the abundance, community structure and metabolic potential of phyllospheric microorganisms. Notably, phyllospheric microorganisms of litter at soil interface had the highest metabolic potential and utilized alcohols as main carbon sources. The characteristics of phyllospheric microorganisms between different treatments were in good agreement with litter decomposition rate, which provides an important theoretical basis for revealing the microbial mechanisms driving the decomposition of wetland plant litter.