Effects of Chitosan Soil Mixture Treatment in the Seedling Stage on the Growth and Flowering of Several Ornamental Plants

Abstract

The effects of 1.0% chitosan [poly-(1 → 4)- β - D-glucosamine] soil mixture and water soluble inorganic fertilizer in soils containing the same amount of nitrogen on the growth and flowering date were investigated on eight species : (Torenia fournieri Linden ex E. Fourn., Exacum affine Balf., Begonia hiemalis Fotsch., Sinningia speciosa (Lodd., Lobelia erinus L., Mimulus hybridus hort. ex A. Siebert et Voss, Calceolaria herbeohybrida Voss and Campanula fragilis L.). Chitosan treatment significantly promoted seedling growth compared to the unfertilized controls and fertilized soil plots containing an equal amount of nitrogen as in chitosan by 6 to 13 weeks after sowing. The first flowering date in chitosan-treated Torenia fournieri Linden ex E. Fourn., Exacum affine Balf., Begonia hiemalis Fotsch., Sinningia speciosa (Lodd., Lobelia erinus L., Mimulus hybridus hort. ex A. Siebert et Voss were significantly earlier than with the other treatments, but not in Calceolaria herbeohybrida Voss and Campanula fragilis L. Thus, chitosan may have an elicitor effect changing the microbiota in soil, according to our preliminary test, or chitosan may be absorbed directly roots and utilized by the plants.