The use of non-saturated lithium chloride solutions for experimental control of seed water content

Non-saturated solutions of Lithium Chloride generate atmospheres greater than 11.1 - 11.3% RH between 5 and 50 degrees C which can be used for equilibrating seeds in experiments where their water content must be controlled e.g. ageing experiments, desiccation experiments, moisture sorption isotherm determination. Making solutions is relatively simple and we present data which enables other practitioners to make tip LiCl solution, with a range of relative humidities at 20 degrees C. There is only a slight effect of temperature on the RH generated by the LiCl solutions between 5 and 45 degrees C. Depending on the volume of solution used and the RH generated and on the volume and initial water content of seed samples, LiCl solutions are relatively stable when used long-term (a few years) and the atmosphere within the air-tight jars which we use for equilibrating seeds reach the correct RH within hours of sealing. Non-saturated LiCl solutions which generate 60% RH are routinely used in this laboratory for seed ageing experiments and we also show how such a solution can be adjusted if there is any change in the RH.