Using steam to reduce artifacts in micro sections prepared with corn starch

Preparation of micro sections to measure cell wall thickness and lumen diameter is a widely used method in the fields of dendroecology, dendroclimatology and tree physiology. Efficient sample preparation and image analysis are critical for studies with long time series and large sample sizes. Recently, there have been substantial improvements in micro section preparation techniques, including a corn starch-based non-Newtonian fluid treatment. This method reduces cell wall damage during cutting with a microtome, which in turn decreases artifacts during image analysis. Although this procedure does in fact improve sample quality, we found starch grains sometimes to be difficult to remove and to cause artifacts during image analysis. This technical note outlines a simple, fast and effective steam treatment that causes starch gelatinization and a reduction in the number of starch grain artifacts.