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 12 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, anticough, 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 4yearold 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 plant1) 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.