[目的]研究短时间不同剂量UV-B辐射对冬小麦幼苗叶片生理指标的影响,为进一步研究植物应答短时间紫外线照射的机理提供参考。[方法]以冬小麦为试验材料,采用15和30μW/cm2的UV-B照射强度对冬小麦幼苗进行短时间照射处理。测定指标包括:①反射光谱值。用Unispec光谱仪测定反射光谱,并计算所得参数,评价UV-B处理前后叶片叶绿素、花色素苷、类胡萝卜素含量、水分含量以及光合强度的变化,每处理测定10片叶;②可溶性蛋白含量。采用考马斯亮蓝G-250法测定叶片的可溶性蛋白含量,牛血清蛋白作为对照;③荧光参数(Fv/Fm):将待测叶片暗反应20min后,用OS-30P荧光仪测定部位同叶色,每处理测定5片叶;④相对电导率。采用Martineau等的方法测定;⑤丙二醛(MDA):采用邹琦的方法测定。测定项目②～⑤均重复5次。[结果]UV-B处理导致叶绿素、可溶性蛋白含量以及含水量都降低,且存在剂量效应,30μW/cm2的降幅大于15μW/cm2;UV-B辐射导致花色素苷和类黄酮含量下降,尤其是处理后2h下降幅度最大,2种剂量的UV-B处理间差异不大。随着处理时间的延长,花色素苷含量呈逐渐上升趋势,其中,30μW/cm2处理的略高于15μW/cm2处理。UV-B辐射处理对类胡萝卜素含量的影响与花青素相同,均表现为先下降后上升的趋势,2种剂量间差异不大;2种剂量的UV-B处理均抑制了PSⅡ的电子传递,尤其是处理2h的抑制作用最大,4、6和8h的抑制有所缓解,且存在剂量效应;2种剂量的UV-B辐射均抑制了叶片的光合速率,随着照射时间的延长抑制效应加大;MDA和相对电导率在照射2h后明显增加,说明高剂量的UV-B处理对膜系统的损伤较大,低剂量的UV-B处理结果不明显。[结论]短时间的UV-B辐射处理对冬小麦幼苗叶片的影响具有剂量效应,高剂量比低剂量的作用效果大。且随着处理时间的延长,受害程度有所减轻,该结果与长时间UV-B照射的结果不同。 [Objective] The research aimed to study the effect of short-term different doses of UV-B radiation on the physiological indexes of winter wheat seedling leaves, and provide a reference for further study on the mechanism of plants responding to UV irradiation in a short time. [Method] The winter wheat was treated with UV-B radiation intensity of 15 and 30 μW / cm2 for a short time with the wheat as test material. Measurement indicators include: ① reflectance spectroscopy. The reflectance spectrum was measured by Unispec spectrometer, and the parameters were calculated. The changes of chlorophyll, anthocyanin, carotenoid content, water content and photosynthetic rate in leaves before and after UV-B treatment were evaluated. The content of soluble protein in each leaf was determined. The content of soluble protein in leaves was determined by Coomassie brilliant blue G-250 method, and the bovine serum albumin was used as a control. (3) Fluorescence parameters (Fv / Fm): The leaves were tested for darkness after 20 minutes, , Each treatment measured 5 leaves; ④ relative conductivity. Using Martineau and other methods determination; ⑤ malondialdehyde (MDA): using Zou Qi method. Measurement items ② ~ ⑤ are repeated 5 times. [Result] UV-B treatment resulted in the decrease of chlorophyll, soluble protein content and water content, and the dose effect was observed. The decrease of 30μW / cm2 was more than 15μW / cm2. The UV-B radiation led to the decrease of anthocyanin and flavonoid content, After 2 hours of treatment the largest decline, two doses of UV-B treatment between the little difference. With the extension of treatment time, anthocyanin content showed a gradual upward trend, of which, 30μW / cm2 treatment slightly higher than 15μW / cm2 treatment. UV-B radiation had the same effect on the carotenoid content as anthocyanin, both of which showed a tendency of first decreasing and then increasing, and there was no significant difference between the two doses. UV-B treatment at 2 doses suppressed the electron emission of PSⅡ Especially 2 h treatment, inhibited at 4, 6 and 8 h, and there was dose effect. UV-B radiation at 2 doses restrained the photosynthetic rate of leaves, and inhibited the photosynthetic rate as the irradiation time prolonged The MDA and relative electrical conductivity increased obviously after 2h exposure, which indicated that high dose of UV-B could damage the membrane system significantly, and the result of low dose UV-B treatment was not obvious. [Conclusion] The effects of short-term UV-B radiation treatment on the leaf of winter wheat seedlings had a dose-effect, and the effects of high-dose and low-dose were significant. And with the extension of treatment time, the degree of victimization has been reduced, the result is different from the results of long-term UV-B irradiation.