It is present in a variety of species: in shells of crustaceans, in cuticles of insects and in the cell wall of fungi and some algae. The deacetylated form of chitin is chitosan. The chitosan biopolymer has applications in waste water treatment, pulp and paper, in medical and cosmetic products, biotechnology, food and feed and membranes [1]. In agriculture, chitosan has been used in seed, leaf, fruit and vegetable coating [2], as fertilizer and in controlled agrochemical release [3], to increase plant product [4–6], to stimulate the immunity of plants [7], to protect plants against microorganisms [8–10] and to stimulate plant growth. In the latter studies, a positive effect of chitosan was observed on the growth of roots, shoots and leaves of various plants including Gerbera [4] and of several crop plants [11]. Orchid roots sprayed with a very diluted chitosan solution show