Response of Grindelia camporum Greene vegetative growth, flowering and resin content to the growing media variation

Gum weed or gum plant (Grindelia camporum Greene, family Asteraceae) is a conspicuously resinous, herbaceous perennial medicinal plant native to the arid regions [1]. Flowers were used clinically for the treatment of asthma, bronchitis, and poison ivy rash [2]. Its resin content is similar to the resin acid (abietic acid) that constitutes rosin (pine resin) and would have the same uses as a principal product in industry. Furthermore, gum weed is an arid adapted plant that grows well under harsh desert condition in low level of irrigation, thus it appears to satisfy the requirements established for new crops in arid environment [3].

A- Abietic acid

B-Grindelic acid

Series groups of arranged pots were separately filled by equal and homogeneous quantities from the growing media separately or in combinations as follow: Loam soil – Loam: sand at rate of 1:1 -Loam: sand: Beat moss at rate of 1:1:1– Sand. The loam soil seems to be the best medium for producing the tallest plants and the heaviest weight of herb and the biggest flower numbers. Further, the highest values from crude resin % (CR%), resin acid number (AN), resin acid (RA%) and crude resin gm/plant were achieved in almost cases from leaves and flowers of plants grown in sand soil as well as combination between loam and sand soil, respectively.

References: [1] Mahmoud, S. (2002) Acta Hort. 576.

[2] Lust, J. (1974) The Herb Book. Bantam books, Inc. New York, USA.

[3] Timmermann, B.N. et al. (1987) Biochem. Syst. Ecol. 15:401–410.