大豆铁素营养诊断适用指标的研究

砂培试验研究大豆铁素营养诊断的生理指标。结果指出:在过氧化氢酶等四种生化指标中,叶片过氧化氢酶不仅能明确指示缺铁症,且测定方法简便,是较好的生化诊断指标。叶片硝酸还原酶、根系细胞色素氧化酶对佐证缺铁症也有辅助作用,过氧化物酶则不具诊断价值。在常规诊断指标中,叶片活性铁含量、叶绿素总量及a/b值对供铁浓度反映敏感,较之植株全铁量,P/Fe、Mn/Fe和Fe/Zn等更能直接反映铁营养状况。 本文提出以叶片过氧化氢酶活性结合活性铁、叶绿素总量和a/b值作早期潜在性缺铁诊断的综合指标。

STUDY ON INDICATORS FOR DIAGNOSIS OF Fe-DEFICIENCY OF SOYBEAN PLANT

Sand culture experiment on soybean cultivar "Zhe Chun" No 2 was carried out to study the indicators for diagnosis of Fe-deficiency. Results showed that: Catalase activity in soybean leaves was quite low when the Fe supply in culture solution was unsufficient to plant, and it increased to a high level as the Fe concentration increased and become relatively stable when Fe level was above 0.5 ppm. This indicates that the enzyme activity can be used as a biochemical indicator for diagnosis of Fe-deficiency. The fact that change in RN activity in leaves and the Grtochrome oxidase activity in roots was influenced by Fe status in soybean plant showed that these two enzymes can alose be used as reference in giagnosis of Fe-deficiency. Under Fe-deficiency the chlorophyll content of soybean leaves decreased while the ratio of chl. a/chl. d increased markedly. When the active Fe content in leaves was below 12 ppm, the symptom of Fe-deficiency appeared. Correlation analysis showed that the total Fe content, Fe/Zn and Mn/Fe in sogybean shoots correlated significanty with active Fe in leaves.It is suggested from the experiment results that the catsiase activity combined with active Fe, and the ratio of Chl. a/Chl. b be used as integrated indicators to predict Fe-deficiency of soybean plant in early development stage.