Abstract

Cynodon dactylon (L.) Pers. is a member of the Poaceae family and has been long used as a medicinal herb in Iranian traditional medicine [1]. Bermudagrass has been reported to possess a variety of medicinal properties such as antiinflammatory, diuretic, astringent, demulcent, aperients, antiemetic, antidiabetic, antiseptic and blood purifying agent. Different part of this plant such as leaves, stolons, rhizomes and culms is a rich source of metabolites such as proteins, carbohydrates, mineral constituents, - sitosterol, flavonoids, alkaloids, glycosides and triterpenoides [2]. Plant growth regulators can change physiological and biochemical characteristics in turfgrasses. Paclobutrazol is used as a plant growth retardant for high maintenance in turfgrass management to suppress shoot growth and improving aesthetic [3]. This pot greenhouse study was conducted to determine if applications of paclobutrazol would result in gainful phytochemical changes in Bermudagrass. Paclobutrazol was applied twice at four weeks intervals at 0, 1, 2, 3 and 4 g a.i. /100 m2 over 8 weeks period. At the end of experiment, severe bermudagrass phytotoxicity occurred from paclobutrazol at 3 and 4 g a.i. /100 m2. Leaves total non-structural carbohydrates (TNC), chlorophyll, flavonoids and soluble protein content increased with increasing paclobutrazol application rate, although no significant difference was found between 3 and 4 g a.i. /100 m2 treatments in TNC, flavonoids and protein content. Total shoot growth was reduced 40%, 58%, 85%, and 91% from 1, 2, 3 and 4 g a.i. /100 m2, respectively. With due attention to phytotoxicity and excessive suppression in shoot growth at high application rates of paclobutrazol, as well as, Minor enhancement in leaves flavonoids content from 0 to 2 g a.i. /100 m2, we suggest that paclobutrazol application is not efficient in improving phytochemical concentration of bermudagrass. Maybe other plant growth regulator such as Trinexapac-ethyl and flurprimidol would be more effective in this purpose.