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为研究紫外(UV-B)辐射增强对拔节-孕穗期麦田植株呼吸和土壤呼吸的温度敏感性的影响,应用静态箱-气相色谱法,于2008年春进行田间试验,观测UV-B辐射增强20%处理以及对照(CK)的麦田生态系统呼吸和土壤呼吸的日变化规律,同时观测温度、湿度等环境因子.结果表明,UV-B辐射增强明显抑制了拔节-孕穗期间麦田生态系统呼吸和土壤呼吸作用,且对土壤呼吸的抑制作用大于对生态系统呼吸的抑制作用,在5次测定中,CK比UV-B处理的日平均生态系统呼吸速率高9%、9%、3%、16%和30%,CK比UV-B处理的日平均土壤呼吸速率分别高99%、93%、106%、38%和10%.CK和UV-B处理植株呼吸的温度敏感系数Q10分别为1.79和1.59,土壤呼吸的Q10分别为1.38和1.76,而生态系统呼吸的Q10则分别为1.65和1.63.UV-B辐射增强导致小麦植株呼吸的温度敏感性降低(Q10值减小),而土壤呼吸的温度敏感性增强(Q10值增大),但UV-B辐射增强对麦田生态系统呼吸的温度敏感性没有明显影响.
In order to study the effect of UV-B radiation on temperature sensitivity of plant respiration and soil respiration in wheat field at jointing-booting stage, a field experiment was conducted in spring 2008 with static box-gas chromatography to observe the enhancement of UV-B radiation by 20 (CK) on the diurnal variation of soil respiration and soil respiration in wheat field as well as the environmental factors such as temperature and humidity were observed.The results showed that enhanced UV-B radiation significantly inhibited the ecosystem respiration and soil Respiration and the inhibition of soil respiration were greater than that of the ecosystem respiration. CK was 9%, 9%, 3% and 16% higher than the average daily average ecosystem respiration of UV-B treatment in 5 measurements And 30% respectively, CK was 99%, 93%, 106%, 38% and 10% higher than the average daily average soil respiration rate of UV-B treatment respectively.The temperature sensitivity coefficients Q10 of CK and UV-B treatment were 1.79 and 1.59 and Q10 of soil respiration were 1.38 and 1.76, respectively, while Q10 of ecosystem respiration was 1.65 and 1.63, respectively. The enhancement of UV-B radiation resulted in the decrease of temperature sensitivity of wheat plants (Q10 value decreased) and the increase of soil respiration Enhanced temperature sensitivity (Q10 value increases), but UV-B radiation Enhancing the temperature sensitivity of wheat field ecosystem respiration did not significantly affect.