How can chitosan strengthen plant growth?
It is well known that chitosan treatment can not only induce disease resistance in plants, but can also promote plant growth. However, the mechanism behind this plant growth promoting effect is not understood at present. Still, the effect is undisputed. In many crop plants, a single seed treatment with chitosan leads to a ca. 25% increase in yield. Just as with the resistance inducing effect, this growth promoting activity of chitosans tended to be unreliable with 'first generation' chitosans but is now consistently reached with the well-defined chitosans available today. Not surprisingly, the effect is more easily reached in less intensive agriculture as practiced in tropical and sub-tropical regions, but when the right chitosan is used, the effects can be stunning even in intensive Western agriculture.