Rotronic water activity measurement helps protect valuable seeds and plants

Bassersdorf, Switzerland: – Leading international measurement solutions specialist Rotronic is playing a leading role in protecting endangered trees and plants with its precise water activity measurement technologies.

Water activity measurement plays an integral role at the Tree Seed Center in British Columbia, where the Tree Seed Working Group seeks to promote tree seed science and technology through research from bud initiation to seed use, identification of seed problems relating to seed improvement and forest management, information exchange of information and consulting on implementation practices.

Water activity continues to be an area of interest to the Tree Seed Working Group, especially with their genetic conservation collection.

Here and at other seed storage facilities around the world, Rotronic has become the standard for water activity measurement.

Free Water Dimension

Although water activity is a relatively new technology to the BC Tree Seed Center, it already plays an important role. Water activity measurement devices from Rotronic offer quick, non-destructive tools for evaluating the free moisture in a sample of seeds.

Free water is often far more relevant to germination, spoilage and shelf life of seeds. The amount of free water in a seed will depend on its relative composition of lipids, starches, and proteins. Storing seed in the freezer with a water activity measurement that is either too high or too low will decrease the longevity of the seed. The ideal level ultimately depends on the species; however, most people now accept the concept of a universal value. At the Tree Seed Center, they keep within a range of 0.35 ± 0.05”.

The Center has adopted Rotronic HP23-AW-A Water Activity Meters as their principal means of measuring free moisture in seeds. The meter outputs a value between 0 and 1, which is equivalent to equilibrium relative humidity (eRH). Aw or eRH differs from a moisture content test in that it only measures the free water rather than the total water content in a sample of seed.

The role of water activity measurement

Currently, water activity is used primarily for testing seed collected for genetic conservation and research. The seeds are often rare and valuable; thus a non-destructive method of assessment is imperative. Collections intended for the seedbank arrive at the Tree Seed Center grouped by population (noted by location), with each population containing, on average, a sample of ten parent trees. Populations are stored in the cooler at 2°C to await an initial water activity assessment. If the water activity is too high, the seeds are dried back and retested prior to placement in the freezer at-18 °C to maximise seed longevity.

In the UK, Rotronic has also worked closely with the Kew Gardens Millennium Seed Bank. Here, a bank of Rotronic devices with direct PC connection are used to screen and test all seeds that are stored in their highly secure underground bunker.

About Rotronic

Rotronic is an international development and manufacturing company that offers a wide range of products and solutions in the B2B segment. Founded in 1965, the company is headquartered in Switzerland and provides solutions for measuring and monitoring relative humidity, temperature, CO2, differential pressure, pressure, flow, dew point, and water activity. The company began the digital transformation already in the year 2000, investing in automated data transfer (machine-to-machine). With the development and launch of its RMS monitoring software, Rotronic further strengthened its position as a key supplier of measurement solutions. As Rotronic is a company of the PST Group (Process Sensing Technologies), our customers are benefitting from a wider product range and distribution network.

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