中文摘要：

【目的】探明油菜素内酯（brassinolide,BR）对阔世玛胁迫下谷子叶片的光合荧光特性及糖代谢的影响,为谷子田磺酰脲类除草剂阔世玛的安全应用及利用植物生长调节剂油菜素内酯缓解除草剂药害提供理论基础和技术途径。【方法】采用完全随机设计,重复3次,以杂交高产谷张杂5号和普通优质谷晋谷21号为材料,进行盆栽试验,待幼苗长至3—5叶期时,喷施7.5 mg·L~（-1）阔世玛,药后1 d,分别叶面喷施清水（对照）、0.05、0.1、0.2和0.4 mg·L~（-1）的油菜素内酯,7 d后对所有处理的谷子幼苗株高、叶面积、鲜重等农艺性状、叶片光合色素含量、气体交换参数、叶绿素荧光参数、糖含量及蔗糖代谢关键酶活性进行测定与分析。【结果】在7.5 mg·L~（-1）阔世玛胁迫下,谷子的株高、叶面积、鲜重、叶绿素a、叶绿素b、类胡萝卜素、叶绿素（a＋b）、净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、最大光化学产量（Fv/Fm）、表观光合电子传递速率（ETR）、非调节性能量耗散量子产量（Y（NO））、中性转化酶（NI）、蔗糖合成酶（SS）及蔗糖磷酸合成酶（SPS）活性显著降低;而胞间CO2浓度（Ci）、调节性能量耗散量子产量（Y（NPQ））、还原性糖、蔗糖和淀粉含量显著升高。药后1 d喷施适宜浓度的BR能部分缓解阔世玛对谷子的药害,显著提高谷子的株高、叶面积、鲜重、光合色素含量、Pn、Tr、Gs、Fv/Fm、ETR、Y（NO）、NI、SS及SPS活性,并显著降低Ci、Y（NPQ）、还原性糖、蔗糖和淀粉含量;其中,0.05—0.1 mg·L~（-1） BR对缓解张杂5号阔世玛药害的效果较好,0.1—0.2 mg·L~（-1） BR对缓解晋谷21号阔世玛药害的效果较好。≥0.4 mg·L~（-1） BR不能缓解阔世玛药害。【结论】7.5 mg·L~（-1）的阔世玛对谷子产生显著药害的原因之一是降低了其光合色素含量,抑制了PSⅡ光化学活性,?

英文摘要：

【Objective】 The effects of brassinolide（BR） on photosynthesis, chlorophyll fluorescence characteristics and carbohydrates metabolism of foxtail millet（Setaria italica） under Sigma Broad stress were explored to provide some theoretical bases and technological approaches for security application of sulfonylurea herbicide and the alleviation of herbicide phytotoxicity in foxtail millet field. 【Method】Completely randomized design and repeated 3 times, using high-yielding hybrid Zhangza 5 and Jigu 21 with general high quality as materials, through pot experiments, applicating 7.5 mg·L~（-1） of Sigma Broad at three-leaf to five-leaf stage, and after 1 d foliar spraying water（CK）, 0.05, 0.1, 0.2 and 0.4 mg·L~（-1） of BR. The effect of BR on growth parameters（plant height, leaf area, fresh mass）, photosynthetic pigment content（Chla, Chlb, Car, Chl（a＋b））, gas exchange parameters, chlorophyll fluorescence parameters, sugar content, activities of key enzyme of sucrose metabolism were determined and analyzed to reveal the effects of BR on modulation of photosynthetic capacity and carbohydrates metabolism by Sigma Broad of foxtail millet after 7 d.【Result】 Sigma Broad significantly decreased plant height, leaf area, fresh mass, photosynthetic pigment content, net photosynthetic rate（Pn）, transpiration rate（Tr）, stomatal conductance（Gs）, the maximum photochemical yield（Fv/Fm）, apparent photosynthetic electron transport rate（ETR）, quantum yield dissipated by non-regulatory energy（Y（NO））, activity of neutral invertase（NI）, sucrose synthetase（SS） and sucrose phosphate synthase（SPS）, but significantly increased intercellular CO2concentration（Ci）, and the quantum yield dissipated by regulatory energy（Y（NPQ）, reducing sugar, sucrose and starch content. One day after Sigma Broad treatment, spraying BR dramatically increased plant height, leaf area, fresh mass, photosynthetic pigment content, Pn, Tr, Gs, Fv/Fm, ETR, Y（NO）, NI, SS and SP