Abstract: To explore the effects of exogenous selenium on morphological characteristics and lodging resistance of oat stem,‘Bayou 18’ was sprayed with different concentrations of sodium selenite (0,16.44,21.92,54.8,65.76,98.64 g·hm^-2) at the heading stage in the field. The changes in morphological,mechanical characteristics and lodging resistance of oat stem were analyzed after spraying selenium for 10,20,30,and 48 days. The results showed that spraying sodium selenite affected the morphological characteristics and anti-lodging ability of oat stalks. With the increase of selenium,the lodging resistance of stalks was increased first and then decreased,and reached the peak in the treatment with 54.8 g·hm^-2 sodium selenite. The lodging resistance index had a significantly positive correlation with oat height,height of gravity center,the second internode diameter,thickness,internode stem fullness,moment of inertia,bending rigidity and mechanical strength (P<0.01),and positively correlated with elastic modulus (P<0.05). Exogenous selenium affected the lodging resistance of oat by influencing the morphological characteristics of oat stem and the strength of the second internode of the stem base. Oat showed the strongest lodging resistance when sprayed with 54.8 g·hm^-2 of sodium selenite during the heading stage.

Key words: Sodium selenite, Oats, Stem characteristics, Lodging resistance

摘要： 为探讨喷施亚硒酸钠对燕麦（Avena sativa L.）茎部形态特征及其抗倒伏能力的影响，本研究以‘坝莜18号’为试验材料，在抽穗期对大田燕麦喷施不同浓度亚硒酸钠（0，16.44，21.92，54.8，65.76，98.64 g·hm^-2），分析在喷硒后10，20，30，48 d燕麦茎部的形态特征、力学特征及抗倒伏性能的变化。结果表明：叶面喷施亚硒酸钠会影响燕麦茎秆的形态特征和抗倒伏能力。随着施硒量的增加，燕麦茎秆抗倒伏能力先升高后降低，并在施硒浓度为54.8 g·hm^-2水平下达到最大值。抗倒伏指数与株高、重心高度、茎秆基部第2节间茎粗、壁厚、节间充实度、惯性矩、抗弯刚度和机械强度之间存在极显著正相关关系（P<0.01），与弹性模量呈显著正相关关系（P<0.05）。外源硒通过影响燕麦茎部形态特征和茎秆基部第二节间的强度，进而影响燕麦的抗倒伏能力。在燕麦抽穗期喷施浓度为54.8 g·hm^-2的亚硒酸钠，其抗倒伏性最强。

关键词: 亚硒酸钠, 燕麦, 茎部特征, 抗倒伏