ALLELOPATHIC EFFECT OF SILYBUM MARIANUM L. GAERTN. ON GROWTH AND NUTRIENT UPTAKE OF WINTER WHEAT (TRITICUM AESTIVUM L.)

Silybum marianum (L.) Gaertn. is a widely known species, however, little is known about its allelopathic potential. S. marianum is a common weed in some crop areas. In this research, the allelopathic effect of S. marianum extracts on Triticum aestivum L. was investigated. The water extracts were used to show its phytotoxicity potential. The examined concentrations (m/v%) were: 1%; 2%; 3%; 4% and 5%. The control was tap water. The fresh and dry weight, the length of coleoptile and the radicle, the element contents of winter wheat seedlings were measured. The low concentration (1%) S. marianum extract had positive effects on the measured parameters. The fresh weight, dry weight and length of the radicle and shoot decreased at higher concentrations. The fresh weight of shoot decreased with 13% at the 5% treatment. The fresh weight of the radicle decreased with 32%, 42% and 67% at the 3%, 4% and 5% water soluble extract treatments. The decrease was significant. The higher concentrations had negative effects on the fresh weight of the shoot and especially of the radicle. The concentration of Ca, Mn, Mo and P increased in the radicle when winter wheat was treated with S. marianum extract, while the Fe and Zn concentrations did not change significantly. Increasing was determined in the N, K and Mg concentration both in the shoot and radicle of winter wheat. According to the results, one possible way is to use of milk thistle active ingredients as natural herbicides in the future. Our results show that we have to pay attention on milk thistle when it is appeared on field such as weed, because it has strong allelopathic effects.