褐化是植物组织培养中一种常见的问题，直接影响组织培养能否成功。为了控制植物组织培养中的褐化现象，选取‘丹黄25’、P138、H21 3个玉米自交系幼胚为外植体，着重探讨胚龄，2,4-D、甘露醇、L-脯氨酸和AgNO3浓度对玉米幼胚愈伤组织褐化的影响。结果表明，选取授粉11天的‘丹黄25’幼胚、13天的P138和H21幼胚接种到诱导培养基中，待长出愈伤后转移到添加2 mg/L 2,4-D、10 g/L甘露醇、10 mg/L L-脯氨酸、10 mg/L硝酸银的继代培养基上，愈伤组织褐化率显著降低，表明培养基的种类及添加物对愈伤组织的生长有重要影响。

Material browning is a universal phenomenon in plant-tissue culture, and it plays a vital role in plant-tissue culture. To control the browing of plant-tissue culture, the immature embryos of three maize inbred lines (‘Danhuang25’, P138, H21) were used in the experiment. Embryo age, 2,4-D concentration, mannitol concentration, L-proline and silver nitrate concentration on the browning of maize calli were studied. The results showed that the embryos selected from ‘Danhuang 25’ (11-day after self-pollination), P138 and H21 (13-day after self-pollination) were inoculated into induction medium and then their callus browning could be significantly inhibited by addition of 2 mg/L 2,4-D, 10 g/L mannitol, 10 mg/L L-proline, 10 mg/L silver nitrate in subculture medium, indicate that the type of medium and additives have a major impact on callus growth.