I would like to measure electrolyte leakage from plant material after exposure to stress. Stress damages cell membrane integrity, resulting in efflux of intracellular components to the surrounding solution. This can be measured by means of an Electrical Conductivity (EC) meter which measures the potential of an electrical current to be transported through water.

Plants have a wide range of electrolytes which leak out of the cell, such as K+, Na+, Cl–, Ca2+, Mg2+, O2-, NO3-, PO43− the list is near endless. When a cell membrane is damaged due to (a)biotic stress, electrolytes leak towards the outside of the cell. A standard protocol to measure such electrolyte leakage can be found here.

I want to make my protocol high-throughput and optimized, and measuring every sample separately with an EC meter is very time demanding. Therefore I wonder if there are specific color reagents or chemical reactions which change their color in response to electrolyte presence. This is much easier to translate to for example a plate format. I find literature on this topic very scarce, I was for instance able to find some on free ion concentration by means of ion increment method, or colorimetric assays for specific ions but nothing as an indicator for EC. Would this theoretically be possible?

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    $\begingroup$ I see as the only chance and only in specific cases some random correlation without causality. $\endgroup$
    – Poutnik
    Commented Apr 14, 2023 at 11:52
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    $\begingroup$ What is the specific electrolyte you want to measure? Is there any reason to believe there are more elecrtolytes in the plant cell than outside? $\endgroup$ Commented Apr 14, 2023 at 22:12

1 Answer 1


A chromogenic polymer-based material with properties very similar to what you are seeking has been developed by the authors of Ref. 1. The color of the partially sulfonated polystyrene particles changes with ionic strength.

From the abstract:

The color of the resulting hydrogel-like ordered structures can be continuously shifted over the entire visible range (405–760 nm) by changing the content of ions over an extremely wide range of concentration (from about 70 μM to 4 M). The optical response is completely independent from pH and temperature, and the initial color can be fully recovered by washing the sulfonated opals with pure water. These new smart photonic materials could find important applications as ionic strength sensors for environmental monitoring as well as for healthcare screening.


  1. Luca Nucara, Vincenzo Piazza, Francesco Greco, Valentina Robbiano, Valentina Cappello, Mauro Gemmi, Franco Cacialli, and Virgilio Mattoli. ACS Applied Materials & Interfaces 2017 9 (5), 4818-4827. DOI: 10.1021/acsami.6b14455
  • $\begingroup$ It is a good step toward the goal. Correlation between ionic strength and conductivity is strong for the (near) same electrolyte diluted to various degree. It is weaker for similar electrolytes and weak generally. But for specific plant scenarios it should be usable. $\endgroup$
    – Poutnik
    Commented Apr 15, 2023 at 7:14
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    $\begingroup$ @Poutnik Yes, the path to a solution often involves many small steps. Hopefully this answer can be of some assistance to the OP in indicating that there might be solutions closely related but perhaps not identical to the one outlined. $\endgroup$
    – Buck Thorn
    Commented Apr 15, 2023 at 7:27
  • $\begingroup$ Thank you, this solution seems very feasible. I will need to review the ion concentration range, and the synthesis possibility of Stimuli-responsive photonic crystals (PCs). $\endgroup$
    – Rivered
    Commented Apr 17, 2023 at 7:32

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