Investigation of Different Root Cutting Treatments on Gum Yield and Survival of Dorema ammoniacum D.Don in South of Sabzevar City

Dorema ammoniacum D.Don (Apiaceae) is a monocarpic species with bulky root and stem height by 1-2 meters, which its gum resin flows in phloem issues. Gum resin has pharmaceutical and industrial properties. In traditional medicine, it has been described as a sputum (expectorant), anticonvulsant, anti-cough, antispasmodic and gastrointestinal drug. In order to compare the different root cutting methods for gum extraction, a factorial experiment was carried out based on randomized complete block design with four replications on 4-year-old Dorema plants in south of Sabzevar city, Iran, in 2016. Treatments consisted of cutting methods (surface and concave), number of root cutting (1 to 4 times) and stopping time after root cutting (2 to 10 days). The results showed that the gum yield in concave method (14.73 gr plant-1) was 56% more than the surface method (9.41 g / plant). In addition, in the surface method, by increasing the number of root cutting from 1 to 4, the amount of gum increased from 6 to 11.8 g per plant. Whereas in the concave method this value was increased from 10.2 to 18 g per plant (p≤0.05). The interaction between number of cutting and stopping time after root cutting showed that two times of cutting with 6 days stopping caused 16 g gum per plant. In terms of survival, 85% of plants (95 bushes) with more than 2 times cutting or 8 to 10 days stopping after root cutting died in the next year.