Traditional medicine, especially herbal medicine, is widely adopted over the world. Concerns regarding the sustainability of the practice of herbal medicine has raised since the extinction of herbs will result in unapplicable prescription. Pinellia ternata is one of the top 10 most prescribed herbal medicine owing to its antitumor and anti-inflammation ability. To achieve sustainability, cultivation practice that take care of soil health should be implemented. Carbon dioxide (CO₂) is an aerial fertiliser that does no harm to soil. Once the level of CO₂ is elevated, photosynthesis rate of C₃ plant is promoted. However, such promotion may be restricted by nitrogen availability. Instead of applying inorganic fertiliser which is harmful to soil, organic fetiliser like chitosan should be enc...[ Read more ]

Traditional medicine, especially herbal medicine, is widely adopted over the world. Concerns regarding the sustainability of the practice of herbal medicine has raised since the extinction of herbs will result in unapplicable prescription. Pinellia ternata is one of the top 10 most prescribed herbal medicine owing to its antitumor and anti-inflammation ability. To achieve sustainability, cultivation practice that take care of soil health should be implemented. Carbon dioxide (CO₂) is an aerial fertiliser that does no harm to soil. Once the level of CO₂ is elevated, photosynthesis rate of C₃ plant is promoted. However, such promotion may be restricted by nitrogen availability. Instead of applying inorganic fertiliser which is harmful to soil, organic fetiliser like chitosan should be encouraged. Chitosan is a natural biocide and plant growth promoter. Since it is soluble in acid and water, it mostly applied in solution form. The applicability as soil amendment as powder has not yet been studied. In this investigation, the effects of chitosan as a soil amendment on the growth and yield of P. ternata is explored by applying 0.1 %, 1.0 % and 5.0 % in soil. Besides, another experiment that study the effects of chitosan as a nitrogen fertiliser on the growth of P. ternata in 1000 ppm CO₂ is performed by adding 1 % and 3 % of chitosan in soil. In first experiment, bulbil growth of chitosan treated P. ternata is enhanced. The active ingredient content is same as untreated bulbil. Bulbil growth of 0.1 % chitosan treated P. ternata is enhanced most significantly as a result of extra nitrogen supply and increment in leaf nitrogen and chlorophyll content. The promotion of photosynthesis rate encourages the biomass accumulation. In second experiment, the active ingredient of 1.0 % chitosan treated bulbil is similar to untreated one, but its growth is better. Extra nitrogen input enlarges the leaf area and improve the radiation interception which result in enhancement in photosynthesis efficiency. In both experiments, high level of chitosan (5.0 % and 3 %) inhibits the root elongation, so nutrient and water uptake is limited. Growth and yield of P. ternata grown in these conditions are not improved. Chitosan can improve the Page growth of P. ternata when it is applied in low concentration. 0.1 % and 1.0 % are suggested when chitosan is applied in ambient and elevated CO₂ condition respectively.