基于微电极技术的温室黄瓜氮胁迫早期诊断技术

Early Diagnosis of Cucumber Nitrogen Stress Based on Microelectrode Technique

为在氮胁迫症状出现之前实现黄瓜的营养诊断,用微电极技术测量4个不同氮水平处理黄瓜叶片的膜电位、膜电容及膜电位对光激励的响应。通过对膜电位变化的研究发现氮胁迫处理黄瓜叶片的膜电位与正常氮处理的膜电位的差异不大,表明不适合用膜电位实现黄瓜氮胁迫的早期诊断;对膜电容变化的研究发现黄瓜叶片膜电容对氮的缺乏情况敏感,可在肉眼可见胁迫症状出现2 d前实现严重和中等氮缺乏的营养诊断;对光激励的膜电位响应的研究发现黄瓜叶片光激励的膜电位响应对氮过量情况敏感,至少可在胁迫症状出现7 d前实现氮过量的营养诊断;表明用微电极技术对黄瓜氮胁迫进行早期诊断是可行的。

To achieve the pre-visual detection on nitrogen （N） stress, the microelectrode technique was used to measure the membrane potential, membrane capacitance and light induced responses of leaf membrane potentials under four different levels of N-treatment, respectively. No obvious difference was found in the membrane potential between N-stress and N-sufficient cucumber leave. It shows that the membrane potentials were not suitable for early diagnosis of N-stress in cucumber plants. The research on the changes of membrane capacitance found that it was sensitive to N-deficiency. The measurement of membrane capacitance could be used for pre-visual diagnosis of severe and moderate N-deficiency 2 d before the appearance of visually morphological changes. The research on the changes of magnitude of leaf membrane potential response to light found that it was sensitive to N-excess. The measurement of the magnitude of leaf membrane potential response to light could be used for pre-visual diagnosis of N-excess at least 7 d before the appearance of visually morphological changes. It shows that the microelectrode technique is suitable for early diagnosis of N-stress in cucumber plants.