Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2001
Publication Date: 12/22/2002
Citation: THIES, J.A. RED FOOD COLORING STAIN: IMPROVED, SAFER PROCEDURE FOR STAINING NEMATODES IN ROOTS AND EGG MASSES ON ROOT SURFACES. JOURNAL OF NEMATOLOGY. 2002. V.34. P.179-181. Interpretive Summary: Staining plant-parasitic nematodes and their egg masses in root tissues is a routine part of research in most plant nematology laboratories worldwide. The ability to visualize plant-parasitic nematodes in root tissue is essential to many areas of plant nematological research including assessments of host plant resistance, elucidation of nematode development and life cycles, and evaluation of efficacies for biocontrol products and traditional nematicides. A number of staining procedures have been developed, however, these methods all require the use of chemical stains that are potentially unsafe to the individual performing the procedure and also result in waste that may harm the environment. Acid fuchsin and phloxine B are two such stains that are widely used for staining nematodes in root tissue and egg masses on the surfaces of roots, respectively. Because of more stringent worker protection standards and new requirements for waste disposal, we developed two improved methods for staining nematodes and egg masses that replace acid fuchsin and phloxine B stains with red food color. Method I: We replaced acid fuchsin stain with a 12.5% solution of red food color that stained nematodes in root tissue a bright red. Method II: We replaced phloxine B with a 20% solution of red food color that stains nematode egg masses a bright red. The substitution of red food color for more toxic stains reduces hazards in performing the technique and also eliminates hazardous waste disposal of these chemicals, which is both costly and may pose hazards to the environment.
Technical Abstract: Staining of nematodes in root tissues and egg masses on root surfaces is a routine part of research in most plant nematology laboratories worldwide. Many of the stains used in plant nematology rely on the use of chemicals with varying degrees of toxicity including acid fuchsin and phloxine B, which are hazardous both to the user and to the environment. Furthermore, such stains must be disposed of through waste disposal companies which involves detailed documentation and record keeping, as well as costs for disposal. We discovered that a 12.5% solution of red food color in distilled H2O was equal to acid fuchsin for staining nematodes in root tissue. We also found that a 20% solution of red food color was equal to phloxine B for staining egg masses on root surfaces. The use of red food color for staining nematodes in root tissue and for staining egg masses on root surfaces are safer for the user and the environment, and eliminate the enecessity for costly waste disposal of used stain solutions.