Lolium arundinaceum leaf and root developmental temperatures influence its allelopathic potency on Poa annua

Abstract

Allelopathy is a commonly recognized but not fully understood method that could be utilized for weed management. Controlled environment studies in a growth chamber were conducted at Virginia Tech's Glade Road Research Facility in Blacksburg, VA, to determine whether aqueous leaf or root extracts from two Lolium arundinaceum (Schreb) Darbysh (tall fescue) cultivars grown under different growing temperature conditions affected the seed germination and growth of Poa annua L. (annual bluegrass). Two cultivars (‘Falcon III’ and ‘Kentucky 31’) of L. arundinaceum were maintained at cold (day/night 4.4:–1.1°C) or warm (day/night 32.2:26.7°C) conditions for 20 d. Leaf and root extracts were collected via destructive methods and applied to P. annua seed placed in petri dishes. The results indicated that aqueous leaf extracts of L. arundinaceum could inhibit P. annua seed germination, though there was no significant germination reduction with the root extract of L. arundinaceum. The results suggest that temperature may interact with other factors, such as L. arundinaceum cultivar, to influence its allelopathic potency on P. annua seed germination. These results further demonstrate that different cultivars of L. arundinaceum might have different allelopathic effects on P. annua germination.