2,4-表油菜素内酯对甜高粱和青贮玉米幼苗耐涝性的影响

为探讨2,4-表油菜素内酯(2,4-epibrassionolide，EBR)对饲草作物种子萌发及幼苗耐涝性的影响，本文研究了甜高粱(Sorghum saccharatum Moench)和青贮玉米(Zea mays)种子萌发及幼苗理化指标对EBR引发种子的响应。结果表明，当EBR浓度为0.01μmol·L^-1时，两种植物的胚芽和胚根长均显著高于其它浓度处理(P<0.05)，且在高浓度时(10μmol·L^-1)胚芽和胚根长均显著低于其它浓度处理。水涝胁迫后，两种植物均表现为株高和干重显著下降(P<0.05)，其中甜高粱株高下降幅度(平均26.25%)大于干重(11.66%)，而青贮玉米干重下降幅度(43.82%)大于株高(20.13%)。EBR引发种子显著提高了水涝胁迫下植株的株高和干重、抗氧化酶活性和游离脯氨酸含量(P<0.05)，降低了丙二醛含量(P<0.05)。综合分析认为，引发通过增加抗氧化酶活性及游离脯氨酸含量，降低膜脂过氧化，最终提高饲草作物幼苗在水涝胁迫下的株高和干重。

Effects of 2,4-Epibrassionolide on Water-Flooding Resistance of Sweet Sorghum and Silage Maize

In order to investigate the influence of seed priming with 2,4-epibrassionolide (EBR) on seed germination and seedling tolerance of forage crops to waterflooding,the responses of seed germination properties and physiological parameters of seedlings to seed priming were evaluated. The results showed that the priming efficiency was depended upon the EBR concentrations,with the highest radicle and germ lengths at 0.01 μmol·L^-1 and the lowest at 10 μmol·L^-1 for both crops. Under the conditions of waterflooding,plant heights and dry weight reduced at three tested stages,about 26.25% decrease for the height of sweet sorghum,which decreased more than dry weight (11.66%). For maize,the dry weights reduced about 43.82%,which decreased more than plant height (20.13%). Overall,EBR priming increased the activities of antioxidative enzymes in plants under waterflooding conditions,resulting in the decrease of malondialdehyde contents and the increase of free proline contents,and finally improved the crop heights and dry weights.