Plant Preservative Mixture (TM) can affect shoot regeneration from leaf explants of chrysanthemum, European birch, and rhododendron

Plant Preservative Mixture(TM) (PPM), a relatively new, broad-spectrum pres ervative and biocide for use in plant tissue culture, was evaluated as an a lternative to the use of conventional antibiotics and fungicides in plant t issue culture. Concentrations of 0.5 to 4.0 mL.L-1 were tested with leaf ex plants of chrysanthemum (Dendranthema xgrandiflora Kitam), European birch ( Betula pendula Roth), and rhododendron (Rhododendron catawbiense Michx.). P PM had little effect on the percentage of explants forming shoots and the n umber of shoots formed per explant in birch and rhododendron, but dramatica lly reduced both responses in chrysanthemum. Therefore, the effects of PPM must be evaluated for each species of interest prior to use.