2005 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement (SCA) between ARS University of Toledo. Additional details of this research can be found in the report for the parent CRIS 3607-21000-008-00D “Develop New or Improved Methods of Hydroponic and Greenhouse Production and Pest Protection.” This SCA is supported by two post-doctoral associates and two PhD students employed through the University of Toledo. A hydroponic system was developed for the model dicot, Arabidopsis thaliana, which permits complete control of the nutrients available to the root system. This has enabled us to identify specific boron (B) concentrations in which root and foliar symptoms begin to develop. Tissues have been harvested for microarray analysis at different stages of B stress. We have also documented the timing and severity of B deficiency in geranium (Pelargonium spp.) and collected ten types of tissue to develop guidelines in which B deficiency can be expected. While the phenotypic and physiological groundwork for the project is being laid, we have also conducted initial analysis of protein changes in geranium in response to toxic and deficient levels of B and we are analyzing samples by 1- and 2-dimensional gel electrophoresis to determine protein changes induced by B. This study is now being extended to A. thaliana, where protein identification is more easily facilitated. Initial exposure of growers to the reaction of geranium to individual nutrient stresses was accomplished through a workshop conducted at a regional growers meeting. In addition to the hands on experience, growers were provided with information and recommendations for early detection of B stress in geranium.