论文部分内容阅读
土壤呼吸(Rs)由自养呼吸(Ra)和异养呼吸(Rh)组成,这两个组分温度敏感性的差异性存在较大争议,而根际激发效应对R_h呼吸速率及其温度敏感性(Q10)的影响导致这一问题更为复杂化。本研究采用~(13)C自然丰度法,将中国北方温带次生林的重要建群树种C_3植物五角槭种植于曾经连续23年种植玉米的C_4土壤中,以此区分R-a和R_h,并探讨R_a和R_h温度敏感性的差异性以及根际激发效应对R_h呼吸速率和Q_(10)的影响。结果表明:植物根系对R_h呼吸速率有负激发效应,并降低了R_h的温度敏感性;植树土壤的R_h比不植树土壤的无根异养呼吸(Rhf)降低了34.3%,R_h的Q_(10)值(1.51)也显著低于R_(hf)的Q_(10)值(2.07),而Ra的Q_(10)值(3.89)是R_h的Q_(10)值的2.5倍;因此,未来研究在区分R_a和R_h呼吸速率和温度敏感性时,应该考虑根际激发效应对R_h及其温度敏感性的影响,这对于精确评估和模型模拟气候变化背景下R_s的变化和响应具有重要意义。
Soil respiration (Rs) is composed of autotrophic respiration (Ra) and heterotrophic respiration (Rh), and the difference in temperature sensitivity of these two components is quite controversial, while the rhizospheric stimulus is sensitive to R_h respiration rate and temperature The impact of sex (Q10) has led to further complications. In this study, ~ (13) C natural abundance method was used to distinguish Ra and R_h from C_3 plants, which are important tree species in the temperate secondary forest of northern China, in C_4 soils that have been maize for 23 consecutive years. And R_h temperature sensitivity as well as the effect of rhizospheric stimulation on R_h respiration rate and Q_ (10). The results showed that the root system of plants had a negative stimulating effect on R_h respiration rate and decreased the temperature sensitivity of R_h. R_h of planting tree decreased 34.3% compared with that of non-rooted soil (Rhf), and Q_ (10) of R_h ) Value (1.51) was also significantly lower than that of Q_ (10) value of R_ (hf) (2.07), while Q_ (10) value of Ra was 3.50 times that of Q_ (10) value of R_h. In distinguishing between R_a and R_h respiration rates and temperature sensitivities, the effect of rhizosphere stimulus on R_h and its temperature sensitivity should be considered, which is important for accurately assessing and modeling the changes and responses of R_s in the context of modeling climate change.