不同耐铝大麦品种对铝锰互作胁迫的生理响应研究

铝（Al）和锰（Mn）是限制酸性土壤作物生长的两大主要因素。以耐铝性差异较大的两个大麦品种为材料，研究了不同处理对大麦生长、叶片功能和氧化胁迫指标的影响。结果表明，与对照相比，铝毒害导致大麦根长下降，根系干物质量降低，锰毒害显著降低植株株高和地上部干物质量，铝锰共存时锰加重大麦铝毒害。铝锰胁迫降低功能叶叶绿素含量和光合能力，复合处理下叶片功能指标下降幅度高于单独铝或锰处理。胁迫处理下叶片功能指标的下降幅度以叶绿素a含量和叶片蒸腾速率最明显。胁迫处理对铝敏感品种的生长和叶片功能毒害强于耐铝品种。铝锰胁迫引起大麦功能叶丙二醛（MDA）含量增加，过氧化物酶（POD）和 超氧化物歧化酶（SOD）活性增强，铝敏感品种增幅更大，复合处理时两品种叶片 MDA 积累量及铝敏感品种 POD 和 SOD 活性增幅显著高于单独铝或锰处理。

Physiological Responses of Barley Plants Differing in Aluminum Tolerance to Aluminum and Manganese Single and Combined Toxicity

Aluminum (Al) and manganese (Mn) toxicity both are the limiting factors for plants growing in acid soil. The nutrient solution experiment was undertaken in the present study to assess the Al, Mn single and combined toxicity on the growth, leaf feature, antioxidant system in barley seedlings and evaluated the different responses to stress treatments of two barley genotypes differing in Al tolerance. The results showed that, Al reduced root growth and root dry weight, while Mn decreased plant height and shoot dry weight, Further, adding Mn in solution enhanced barley Al toxicity. Stress treatments decreased the chlorophyll content and photosynthesis, especially for chlorophyll a content and leaf evaporation under combined toxicity. The toxicity to plant growth and leaf function were more serious in Al-sensitive genotype compared with the tolerant genotype. Al and Mn treatments increased MDA content and the activities of SOD and POD in barley leaves for two barley genotypes, especially for Al sensitive genotype. The increases of MDA content in both barley genotypes and activities of POD, SOD in Al sensitive genotype were more obvious under the combined toxicity than single Al or Mn treatments.