香豆素对入侵植物节节麦种子萌发及幼苗生长的影响

为探讨利用化感物质香豆素对入侵植物节节麦Aegilops tauschii进行生物防控的可行性，采用培养皿生物检测法，研究了50，100，150 mg·L-1等3种质量浓度香豆素溶液对其种子萌发及幼苗生长和生理生化指标的影响。结果表明:随质量浓度的增加，香豆素溶液显著降低了节节麦种子发芽率、发芽指数，以及幼苗苗高和根长的生长。从抑制率（R_I）可知，香豆素溶液对节节麦种子萌发及幼苗生长存在质量浓度效应的抑制作用。此外，不同质量浓度香豆素溶液处理对根长的R_I值均明显大于苗高，表明香豆素对节节麦幼苗根长生长的抑制作用大于苗高。幼苗生长试验中，仅50 mg·L-1溶液处理中，至第10天时相对电导率及丙二醛质量摩尔浓度较第5天时增加未达到显著水平，这可能是节节麦通过自身调节机制对香豆素造成的损伤进行积极修复的结果。而150 mg·L-1溶液处理中，至第15天时脯氨酸质量分数较第10天时增加不显著，而超氧化物歧化酶活性则呈下降趋势。表明香豆素150 mg·L-1溶液处理第15天已超出节节麦的适应承受范围。以上结果显示:150 mg·L-1香豆素溶液对节节麦种子萌发具有较强的化感抑制作用，并通过影响植株抗氧化酶系统、细胞膜透性及膜脂过氧化作用等途径调节节节麦的生长。

Seed germination and seedling growth of invasive Aegilops tauschii with application of coumarin

To determine the allelopathic inhibition of coumarin on Aegilops tauschii and the feasibility of using coumarin as a biological method for invasive plant control, the effects of coumarin with different concentrations (50, 100, 150 mg·L-1) on A. tauschii seed germination and seedling growth were evaluated in a sand-culture experiment. Results showed that compared with a control, the germination rate, germination index, growth of seedling height, and root length were inhibited with increase of coumarin solution treatment. The inhibitory effect of coumarin on the growth of root length was greater than that of seedling height based on the value of the inhibition rate. Only with the 50 mg·L-1 coumarin solution treatment did the relative conductivity and MDA content not increase significantly at 10 d compared with at 5 d (P < 0.05). With the 150 mg·L-1 coumarin solution treatment, the proline content did not increase significantly, and the superoxide dismutase (SOD) activity decreased at 15 d compared with at 10 d. The above results indicated that 150 mg·L-1 coumarin solution had a strong allelopathic and inhibitory effect on seed germination of A. tauschii and could regulate seedling growth of A. tauschii by changing antioxidant enzyme systems, cell membrane permeability, and membrane lipid peroxidation.