紫外（UV-B）辐射增强对拔节-孕穗期小麦植株呼吸和土壤呼吸的温度敏感性影响

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.

Temperature Sensitivity of Wheat Plant Respiration and Soil Respiration Influenced by Increased UV-B Radiation from Elongation to Flowering Periods

Field experiment was carried out in the spring of 2008 in order to investigate the effects of increased UV-B radiation on the temperature sensitivity of wheat plant respiration and soil respiration from elongation to flowering periods. Static chamber-gas chromatography method was used to measure ecosystem respiration and soil respiration under 20% UV-B radiation increase and control. Environmental factors such as temperature and moisture were also measured. Results indicated that supplemental UV-B radiation inhibited the ecosystem respiration and soil respiration from wheat elongation to flowering periods, and the inhibition effect was more obvious for soil respiration than for ecosystem respiration. Ecosystem respiration rates, on daily average, were 9%, 9%, 3%, 16% and 30% higher for control than for UV-B treatment for the five measurement days, while soil respiration rates were 99%, 93%, 106%, 38% and 10% higher for control than for UV-B treatment. The Q₁₀s (temperature sensitivity coefficients) for plant respiration under control and UV-B treatments were 1.79 and 1.59, respectively, while the Q₁₀s for soil respiration were 1.38 and 1.76, respectively. The Q₁₀s for ecosystem respiration were 1.65 and 1.63 under CK and UV-B treatments, respectively. Supplemental UV-B radiation caused a lower Q₁₀ for plant respiration and a higher Q₁₀ for soil respiration, although no significant effect of supplemental UV-B radiation on the Q₁₀ for ecosystem respiration was found.