Abstract:

Effects of chitosan oligomers and polymer on in vitro development of perennial ryegrass (Lolium perenne L.), red fescue (Festuca rubra L.), and Kentucky bluegrass (Poa pratensis L.) were studied to elucidate a possible differentiation between the effects of chitosan depending on its chemical structure. The seed germination rate was enhanced after the oligomer treatments. The oligomer mixture triggered leaf elongation better than the polymer. However, the highest number of leaves was found from L. perenne in the polymer's presence at 10 mg·L-1 in the medium. The maximum leaf length was reached in L. perenne after oligomeric chitosan treatment at 5 mg·L-1. The plant's rhizogenic response was enhanced in P. pratensis but decreased in L. perenne and F. rubra after 2.5 mg·L-1 oligomeric chitosan treatment. However, the root elongation was restricted in F. rubra and P. pratensis after chitosan treatments. Conversely, chitosan treatments augmented root elongation in L. perenne. This study suggested that chitosan might be preferred to ensure better turf coverage in these grass species. However, constant- or over-treatment with chitosan could reduce root growth and increase the plant's leaf elongation that might contribute to nutritional deficiency and increased mowing costs, respectively.

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