花生缺铁黄化的敏感时期及耐低铁品种的筛选指标

采用盆栽试验，系统研究了石灰性土壤上16个花生品种在各个生育时期新叶的黄化度、叶绿素值、活性铁含量的差异及其动态变化。结果表明，缺铁胁迫下花生耐低铁和铁敏感品种间叶片的黄化程度存在着显著差异，大多数铁敏感品种在出苗后50～65 d时黄化度最高。供试16个品种顶部新展开叶片的叶绿素值（SPAD值）和活性铁含量在整个生育期的变幅分别为4.5～34.6和8.0～36.3 mg/kg, FW，随生长时间的延长两者均呈高―低―高的动态变化趋势。在生长前期，耐低铁品种新叶的叶绿素值和活性铁含量均显著高于铁敏感品种；开花期是花生对缺铁胁迫最为敏感的时期，此阶段黄化现象最严重、各品种新叶的叶绿素值和活性铁含量最低。相关分析表明，在生长前期叶绿素值与黄化度、活性铁及荚果产量之间均呈极显著的相关关系。新叶叶绿素值可作为花生耐低铁品种筛选的一可靠指标。

Study on the sensitive period and screening index for iron deficiency chlorosis in peanut

A pot experiment was done for sixteen peanut euhivars grown on a calcareous soil. Genetic differences in chlorosis score, active Fe concentration and SPAD value in newly expanded leaves and their dynamic changes within the growth season were also analyzed. Results showed that under iron deficiency stress, significant differences in chlorosis degree were existed between iron-resistant and iron-susceptible peanut cultivars. The highest chlorosis scores for suscepti-ble cuhivars appeared at 50-65 days after emergence. During the growth season, SPAD value and active Fe contents in the newly expanded leaves varied in the range of 4.5-3.6 and 8.0-36.3 mg/kg, FW, respectively. Tendency of these two parameters changed from high to low to high with time. At early growth stage, SPAD value and active Fe content in young leaves of iron-resistant eultivars were significantly higher than those of iron-susceptible ones. Flowering stage was the most sensitive period to iron deficiency when the most severe chlorosis was observed, and the lowest SPAD value and active Fe content in young leaves were tested. Highly significant correlations were found between SPAD value and chloro-sis score, active Fe content and pod yield at early growth stage. SPAD value in young leaves can be a feasible screening indicator to select iron-resistant peanut cultivars.