青蒿素对牧草的化感作用

试验以黑麦草、白三叶和光叶紫花苕为材料,采用盆栽试验,研究不同浓度(0,6,12,24,36mg/kg)青蒿素处理对3种牧草生长、生理、抗氧化酶和养分指标的影响,为重庆市黄花蒿产区选择宜栽牧草提供科学参考。结果表明,青蒿素显著影响3种牧草生长,影响效应与青蒿素浓度和牧草种类显著相关。其中,6mg/kg青蒿素对3种牧草生长指标均有显著抑制作用,并随浓度的增加而增强。当浓度为36mg/kg时,黑麦草、白三叶和光叶紫花苕的生物量分别减少76.83%,90.10%和65.09%;株高分别降低47.82%,38.76%和44.49%。青蒿素对3种牧草的化感综合效应均表现为负值,且绝对平均值光叶紫花苕最小,黑麦草次之,白三叶最大,说明光叶紫花苕对青蒿素相对不敏感。此外,青蒿素显著降低牧草叶绿素含量、根系活力和硝酸还原酶活性,不益于光合作用、养分吸收和氮素同化,故牧草氮、磷、钾吸收量显著降低,最大降幅均超过70%。青蒿素对抗氧化酶活性的影响各异,超氧化物歧化酶活性提高,过氧化物酶活性降低,过氧化氢酶活性无显著变化。但是,青蒿素大幅度提高丙二醛含量,表明在青蒿素胁迫下,牧草体内产生了较多的氧自由基或清除率降低,细胞膜受到损伤。因此,在重庆黄花蒿产区,比较适合种植对青蒿素相对不敏感的光叶紫花苕。

Allelopathic effects of artemisinin on pasture grasses

Artemisiaannua,which grows in many parts of Chongqing,releases artemisinin,which can inhibit the growth of surrounding plants.To identify pasture grasses that can grow in areas with abundant A.annua, we conducted a pot experiment to study the effects of artemisinin on grass growth.We evaluated the growth, physiology,antioxidant enzyme activity,and nutrient uptake of three pasture grasses (Loliumperenne,Trifo-liumrepens,and Viciavillosa)growing in soil with artemisinin at different concentrations (0 ,control;6 ,12 , 24,36 mg/kg soil).Artemisinin significantly affected the growth of all three pasture grasses,and the effects differed depending on the artemisinin concentration and the grass species.At 6 mg/kg,artemisinin led to sig-nificant decreases in growth indexes and the degree of inhibition increased with increasing artemisinin concen-trations.Compared with their respective controls,L.perenne,T.repens,and V.villosaplants grown with artemisinin at 36 mg/kg showed 76.83%,90.10%,and 65.09% decreases in biomass,respectively,and 47.82%,38.76% and 44.49% decreases in plant height,respectively.Artemisinin had a negative allelopathic effect on all three pasture grasses,with the strongest effect onT.repens,followed byL.perenneand thenV.villosa,indicating thatV.villosawas the least sensitive to artemisinin.Therefore,V.villosamay be the most adaptable of the three tested grasses to growth in areas of Chongqing with abundant A.annua.In addition,ar-temisinin significantly reduced the chlorophyll content,root vigor,nitrate reductase activity,photosynthetic rate,root nutrient uptake,and nitrogen assimilation in all of the tested grasses.As a result,the uptake of ni-trogen,phosphorus,and potassium by pasture grasses was decreased by more than 80%.The activity of pro-tective oxidases in pasture grasses varied in response to artemisinin,with superoxide dismutase showing in-creased activity,peroxidase showing decreased activity,and catalase showing no significant change in activity. However,artemisinin greatly increased the malondialdehyde content in all three pasture grasses,suggesting that more oxyradicals were produced or less oxyradicals were eliminated,leading to cell membrane damage.