Vascular sap measurement sensor

A vascular sap measurement sensor comprising:

• an indicator electrode probe that includes an indicator electrode which is an ion-sensitive field effect transistor;
• a reference electrode probe that includes a solid reference electrode, the solid reference electrode including a base layer, a silver chloride layer, and a chloride layer, the base layer being formed of an electrically conductive body, the silver chloride layer being formed on a surface of the base layer, the chloride layer being formed on a surface of the silver chloride layer;
• an electrical conductivity probe that includes an electrical conductivity electrode pair, the electrical conductivity electrode pair including a pair of electrodes disposed at a predetermined interval;
• and
• a supporting portion that supports the indicator electrode probe, the reference electrode probe and the electrical conductivity probe arranged in parallel, wherein each of the pair of electrodes includes a metal layer that covers a top surface and side surfaces of a projection formed on a probe surface.