湖南是我国双季稻主产区，在晚稻灌浆期可能出现极端低温天气，造成水稻减产。为明确增施生物炭在灌浆期低温下对晚稻抗氧化酶活性和产量的影响，以主推品种泰优390和传统品种湘晚籼1号为材料开展盆栽试验。试验设置3个施肥处理和2个灌浆期温度处理。施肥处理为常规施肥（NPK）、常规施肥+增施土壤质量5%的生物炭（NPK+BC）和常规施肥+增施与生物炭中所含N、P、K等量的化肥（NPK+），灌浆期温度处理为常温（环境温度）和低温（日均温17 ℃）。结果表明，与灌浆期常温处理相比，低温胁迫下泰优390和湘晚籼1号的产量分别下降35.85%和27.70%；2个品种的产量下降幅度均表现为NPK+BC<NPK<NPK+，且处理间存在显著差异；在灌浆期低温胁迫下，产量下降幅度与结实率极显著负相关，而与有效穗数和每穗总粒数的相关性不显著；与灌浆期常温处理相比，灌浆期低温胁迫下泰优390和湘晚籼1号剑叶和根系的POD（过氧化物酶）、CAT（过氧化氢酶）活性以及MDA（丙二醛）含量均提高；在灌浆期低温胁迫下，2个水稻品种剑叶和根系中的POD、SOD（超氧化物歧化酶）和CAT酶活性均表现为NPK+BC处理显著高于NPK和NPK+处理。总的来看，灌浆期低温胁迫导致晚稻产量降低，但是增施生物炭可以减少产量损失，这可能与生物炭提高了灌浆期低温胁迫下晚稻结实率和抗氧化酶活性有关。

Hunan is the main production area of double cropping rice in China. The extreme low temperature weather that may occur during the filling stage of late rice will cause rice yield reduction. In order to clarify the effect of increasing the application of biochar application on antioxidant enzyme activity and yield of late rice under low temperature at filling stage, a pot experiment was carried out with the rice variety Taiyou 390 and Xiangwanxian 1 as materials. The experiment set up three fertilization treatments and two temperature treatments at filling stage. Fertilization treatment includes conventional fertilization (NPK), conventional fertilization+increased application of biochar with 5% of soil weight (NPK+BC), and conventional fertilization+increased application of chemical fertilizer with the same amount of N, P, K contained in biochar (NPK+). The temperature treatments during the filling period are normal temperature (environment temperature) and low temperature (daily average temperature 17 ℃). The results showed that, compared with normal temperature at filling stage, the yield of Taiyou 390 and Xiangwanxian 1 decreased by 35.85% and 27.70% respectively at low temperature. The yield of the two rice varieties decreased in the order of NPK+BC<NPK<NPK+, and there were significant differences. Under low temperature stress at filling stage, the decrease of yield was very significantly negatively correlated with seed setting rate, but not significantly correlated with effective panicle number and grain number per panicle. Compared with normal temperature at filling stage, POD, CAT activity and MDA content in flag leaves and roots of Taiyou 390 and Xiangwanxian 1 increased under low temperature stress. At low temperature during filling stage, the activities of POD, SOD and CAT in flag leaves and roots of the two rice varieties were significantly higher in NPK+BC treatment than in NPK and NPK+ treatments. In conclusion, the low temperature stress at the filling stage led to the reduction of the yield of late rice, but the increasing the application of biochar could reduce the yield loss, which might be related to the increase of seed setting rate and antioxidant enzyme activity of late rice under low temperature stress at the filling stage.