中文摘要：

以耐碱性燕麦品种Vao-9和碱敏感性品种白燕5号为试验材料，采用盆栽法，用25、50、75和100mmolL^-1碱浓度（Na2CO3和NaHC03按摩尔比1：1混合）进行短期（14d）和长期（28d）胁迫处理，观测两品种根、茎、叶中Na^＋、K^＋、Ca^2＋、Mg^2＋吸收及分配特点，并从离子平衡吸收与分配角度，探讨燕麦对碱胁迫的生理适应机制。胁迫处理14d后，燕麦体内Na^＋增加，K^＋下降，Ca^2＋和Mg抖变化不大，且两品种间各器官中4种离子的分配比例差异不显著。胁迫处理28d后，两品种各器官中Na＋增幅较大，心、Ca^2＋和Mg^2＋降幅较大。Vao-9植株体内Na^＋、Ca^2＋含量大于白燕5号，但0、Mg^2＋含量与白燕5号无显著差异，但两品种间各器官中4种离子的分配特点不同；当胁迫浓度达到100mmolL^-1时，与白燕5号相比，Vao-9叶片中少分配5．9个百分点Na^＋，多分配13．5个百分点心、28．9个百分点Ca^2＋、10．9个百分点Mg^2＋，茎中多分配5．4个百分点Na^＋，少分配9．8个百分点心，根中少分配28．9个百分点Ca^2＋、10．9个百分点Mg^2＋，因而Vao-9叶片中Na^＋／K^＋、Na^＋／Ca^2＋、Na^＋／Mg^2＋值较白燕5号低。可见，燕麦通过提高阳离子选择吸收及器官分配能力以适应碱胁迫。

英文摘要：

In a pot experiment, an alkali-tolerant oat variety, Vao-9, and an alkali-sensitive variety, Baiyan 5, were exposed to 25, 50, 75, and 100 mmol L-t of alkali stress （molar ratio of Na2CO3：NaHCO3 = 1：1）. The contents of Na^＋, K^＋, Ca^2＋, and Mg^2＋ ab- sorbed by oat seedling and their distribution characteristics in root, stem, and leaf were measured after a short-term （14 d） or a long-term （28 d） stress treatment. The objective was to understand the physiological adaptation to alkali stress in oat in the view of ion balance absorption and distribution. After short-term stress, the cation contents in oat plants showed the variations of increased Na^＋, decreased K^＋, and minor changes in Ca^2＋ and Mg^2＋. Besides, the distribution proportions of the four ions in various organs were not significantly different between the two varieties. Compared to short-term stress, long-term stress resulted in larger in- crease ofNa^＋ content and larger decreases of K^＋, Ca^2＋, and Mg^2＋ contents in all organs of both varieties. Vao-9 absorbed more Na^＋ and Ca^2＋ than Baiyan 5, and the absorptions ofK^＋ and Mg^2＋ were not significantly different between varieties, but the distribution characteristics of the four ions in various organs were different between the two varieties. Under 100 mmol L-1 alkali stress, 5.9 percent Na^＋ in leaf were lower distributed and 13.5 percent K^＋, 28.9 Ca^2＋, 10.9 Mg^2＋ more distributed in Vao-9 than in Baiyan 5, 5.4 percent Na^＋ in stem higher and 9.8 K^＋ lower in Vao-9 than in Baiyan 5, 28.9 Ca^2＋, 10.9 Mg^2＋ in root were lower in Vao-9 than in Baiyan 5, As a result, the Na^＋ content and the ratios of Na^＋/K^＋, Na^＋/Ca^2＋, and Na^＋/Mg^2＋ in leaf were lower in Vao-9 than in Baiyan 5. Clearly, oat plant has the mechanism of selective absorption and distribution of various cations in different organs in response to alkali stress.