(1) 中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室

In this work,we constructed a novel microelectrode for stable pH monitoring for in-situ determination of plant tissues.The Ir was electrochemically modified by cyclic voltammetry under alkaline conditions to obtain a pH-type electrode of Ir/Ir(OH)_x.The morphology and electrochemical properties of electrodes were studied.The results show that a layer of white Ir(OH)_x film is formed on the surface of the electrochemically modified silk.The electrode is sensitive to pH and the potential and pH are Nernst linear response in the range of pH=4-10.The response time of the electrode is about 60 s,and the electrode has good stability by many times interval measuring.The in-situ measurement of the growth condition of the plant culture process was carried out by using the electrode.It was found that the pH of the Epipremnum aureum had slight decrease under cultivating in the hydroponic solution of the weak acid salt,and the stem of the plant showed a hysteresis trend compared with the rhizome.Therefore,the iridium needle electrode can be used to measure the in situ pH value of plant tissues.