Assessment of Allelopathic Potential of Some Weed Species on Alfalfa(Medicago sativa L.) Germination and Early Seedling Growth

알팔파 발아와 초기생육에 대한 잡초종의 Allelopathic 잠재성 평가

Greenhouse and laboratory studies were conducted to investigate allelopathic potential of some weed species on alfalfa(Medicago sativa L.) germination and seedling growth. In the comparison between top(leaves+stems) and root extracts, top extract exhibited greater allelopathic effects on alfalfa germination than that of root. The various weed species extract differently responded to alfalfa test species, WL-320, in terms of allelopathic effect. Top and root aqueous extracts of lambsquarter(Chenopodium album L.), giant foxtail(Setaria faberii Herrm.), redroot pigweed (Amaranthus retroflexus L.), velvetleaf(Abutilon theophrasti Medic.), crabgrass(Digitaria sanguinalis L.), canada thistle(Cirsium arvense L.) and prostrate knotweed(Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, vigor, and rate of germination of alfalfa. The regression slopes of various top extracts showed that velvetleaf(b=3.69) extracts were the most inhibitory, while large crabgrass(b=2.39) extracts had the least allelopathic effect on alfalfa germination. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Also, more of the toxic effects were observed from the dried extracts compared to the fresh extracts. Residue of velvetleaf inhibited significantly alfalfa emergence and survival percentage compared to the control. The emergence and survival percentage of alfalfa were 44%, 57% at 1.0% residue treatment, respectively. When weed residues were mixed with silica sand with incubation time, velvetleaf residue most inhibited alfalfa growth. The degree of inhibition increased as incubation time increased. An incubation for 72h caused the greatest inhibition of alfalfa growth. These results demonstrate the different allelopathic activity of weed species extracts on alfalfa and suggest that weed may affect alfalfa growth and development through the inhibitory effects of allelochemicals present in weed tissue.

본 실험은 알팔파 발아와 초기생육에 대한 canada thist1e 등 7종잡초의 allelopathic 잠재성을 평가하기 위해서 실시하였다. 1. 7종류 잡초의 지상부와 지하부 추출물의 알팔파 발아와 생육에 대한 억제효과를 비교하면 두 추출물이 공히 알팔파 발아와 생육에 억제적으로 작용하였으나, 지상부의 추출물이 지하부의 추출물보다 더 큰 억제작용을 보였으며, 이 중에서 velvetleaf 추출물이 가장 억제적이었고(b=3.69), crabgrass 추출물은 가장 낮은 억제정도를 보였다(b=2.39). 2. 농도에 따른 velvetleaf 추출물 처리에서는 농도가 증가할수록 alfalfa 발아율, 유근의 길이, 무게 등이 대조구외 비교하여 상대적으로 더 억제되었으며, 알팔파 발아와 유근의 생육에 대한 velvetleaf의 건조 추출물과 생체 추출물을 비교하면 건조 추출물이 더 억제적으로 작용하였다. 3. 건조된 velvetleaf를 silica sand와 혼합처리시 혼합비율이 증가될수록 알팔파의 초기 출현율과 생존율이 더 억제되었으며 혼합비율 1%에서는 출현율과 생존율이 44.0%, 56.7%로 가장 낮았다. 4. 잡초 잔기의 처리시간에 따른 알팔파 초기 생육에 대한 억제작용은 처리시간의 증가와 더불어 알팔파 생장이 억제되었고, 그 억제정도는 velvetleaf 72시간 처리시 가장 높았다.