Alfalfa Suppresses Mugwort (Artemisia vulgaris): Does Allelopathy Play a Role?
Gaziosmanpasa University, Faculty of Agriculture, Department of Plant Protection, 60240 Tokat, Turkey.
Alfalfa is known suppressing mugwort under the field conditions. The objective of this study was to assess the extent of allelopathy in the alfalfa-mugwort interaction under the greenhouse and laboratory conditions. The above-ground (AGAB) and under-ground alfalfa biomasses (UGAB), and of water extracts were used to determine the allelopathic effect of alfalfa on mugwort. The sprout of mugwort rhizomes or seed germination, growth of seedlings and leaf color changes in mugwort seedlings were evaluated in pot experiments. Soil incorporated AGAB was highly inhibitory on sprouting of mugwort rhizome fragments and growth of seedlings. The inhibitory effect was increased, and gradual leaf discoloration (yellowing) was observed with the greater doses of soil incorporated AGAB. However, soil incorporated UGAB had no affect on sprouting of mugwort rhizome fragments and growth of seedlings, and leaf discoloration was also not observed. Post-emergence applied alfalfa extracts did not significantly affect growth of mugwort seedlings. AGAB and UGAB water extracts resulted in significant reduction of the seed germination and seedling growth in the petri dishes experiments. However, the inhibitory effects of AGAB extracts were greater than that of UGAB. The inhibitory effect of extracts on radicle growth was severer than that on hypocotyl growth. Mean germination time was also negatively affected by extracts, and increased progressively with increasing extract concentrations. The results indicated that especially AGAB may have some allelochemicals. Thus, the allelopathic effect of alfalfa along with competitive ability and harvesting regime may play important role in suppressing mugwort growth.
Key words: Allelopathy, germination, rhizome sprouting, seedling growth, leaf color.