ARS | Publication request: Evaluation of Four Amendments as Sources of Available Silicon to Accumulator Plants Grown in Soilless Media

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 4, 2009
Publication Date: June 15, 2009
Citation: Locke, J.C., Frantz, J., Krause, C.R. 2009. Evaluation of Four Amendments as Sources of Available Silicon to Accumulator Plants Grown in Soilless Media. Phytopathology. 99:(S)76.

Technical Abstract: As part of an on-going project to evaluate the potential of silicon to reduce biotic and abiotic stresses in floricultural crop production, four amendments were incorporated into a standard soilless growing medium (Sunshine Mix #2) prior to transplanting three-week-old seedling plugs of sunflower and zinnia. The same amendment-medium combinations were extracted in a ten-extraction series using the Saturated Media Extraction (SME) technique in the laboratory and analyzed with inductively coupled plasma atomic emission spectrometry (ICP-AES). The plugs were grown utilizing quarter-strength Hoagland’s nutrient solution (equivalent to 50 ppm N) made with deionized water (18 uohm purity) to minimize exposure to silicon prior to transplant. Plants grown in unamended medium served to establish baseline levels of silicon accumulation for analytical comparisons of tissues utilizing scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDXA) and ICP-AES. The amendments evaluated included: calcium silicate slag, parboiled rice hulls, chopped switchgrass straw, and coconut coir. Leaf tissue was harvested at 2, 5, and 8 weeks after transplant to determine a timeline for silicon uptake/accumulation. These accumulation rates were compared to the SME results to determine the predictive power of standard laboratory soil analysis methods for silicon accumulation potential. Together, these data describe approaches for reliable and effective delivery of silicon to silicon-accumulating crops.