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United States Department of Agriculture

Agricultural Research Service

Research Project: RESEARCH TO DEVELOP STRATEGIES AND TECHNOLOGIES FOR PRESERVING PLANT GENETIC DIVERSITY IN EX SITU GENEBANKS Title: Seed Storage Containers: Implications of water permeability properties on moisture management

Authors
item Walters, Christina
item Hill, Lisa

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 16, 2009
Publication Date: May 1, 2009
Citation: Walters, C.T., Hill, L.M. Seed Storage Containers: Implications of water permeability properties on moisture management. Seed Technologists Newsletter. 83 (2):23. Association of Official Seed Analysts and Society for Commercial Seed Technologists. May 29-June 4, 2009. Fort Collins, Colorado. Meeting Abstract.

Interpretive Summary: Seed moisture must be controlled to maintain high seed quality. Moisture control is accomplished by adjusting or conditioning relative humidity and temperature surrounding the seed. Seeds are packaged in moisture-proof containers to maintain the desired moisture content. The effectiveness of containers as moisture barriers varies with the materials used, and water vapor permeation rates for most materials are known. Specifications when purchasing seed containers should be based on these known water vapor permeation rates as well as the outside environmental conditions and the time that the seed is expected to remain as inventory. While no package is completely moisture-proof, packaging that is highly impermeable to water will help to maintain a near constant seed water content. However, another problem may arise with moisture-proof containers if temperature is not also controlled. Using data loggers, we can demonstrate that relative humidity increases during warming of seed-filled containers and decreases during cooling. Thus, temperature fluctuations can cause fluctuations of relative humidity (RH) within moisture proof packaging. These fluctuations are predicted by water sorption isotherms, which describe temperature-RH-water content interactions within seeds. Elevated RH from warming seeds in sealed bags can cause them to deteriorate faster than expected and reduce the benefit gained from an expensive moisture barrier.

Technical Abstract: Seed moisture must be controlled to maintain high seed quality. Moisture control is accomplished by adjusting or conditioning relative humidity and temperature surrounding the seed. Seeds are packaged in moisture-proof containers to maintain the desired moisture content. The effectiveness of containers as moisture barriers varies with the materials used, and water vapor permeation rates for most materials are known. Specifications when purchasing seed containers should be based on these known water vapor permeation rates as well as the outside environmental conditions and the time that the seed is expected to remain as inventory. While no package is completely moisture-proof, packaging that is highly impermeable to water will help to maintain a near constant seed water content. However, another problem may arise with moisture-proof containers if temperature is not also controlled. Using data loggers, we can demonstrate that relative humidity increases during warming of seed-filled containers and decreases during cooling. Thus, temperature fluctuations can cause fluctuations of relative humidity (RH) within moisture proof packaging. These fluctuations are predicted by water sorption isotherms, which describe temperature-RH-water content interactions within seeds. Elevated RH from warming seeds in sealed bags can cause them to deteriorate faster than expected and reduce the benefit gained from an expensive moisture barrier.

Last Modified: 12/22/2014
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