胡桃醌对小麦种子萌发及幼苗生长的化感效应

以小麦种子为试验材料,采用培养皿药膜法、生化分析法研究了胡桃醌对小麦种子萌发和幼苗生长的化感效应。结果显示:(1)与对照相比,低浓度胡桃醌(4和20μmol.L-1)处理能促进小麦种子萌发和幼苗生长,种子α-淀粉酶活性增大,幼苗中可溶性蛋白含量升高,丙二醛(MDA)含量减少,超氧化物歧化酶(SOD)活性无显著变化。(2)当胡桃醌浓度大于100μmol.L-1时,对小麦种子萌发和幼苗生长开始呈现抑制作用,种子α-淀粉酶活力降低,幼苗相对含水量、可溶性蛋白含量降低,MDA含量升高,SOD活性先增大后减小。(3)在最大浓度胡桃醌(1 250μmol.L-1)处理下,小麦幼根的细胞形状不规则,排列混乱,层次不分明,维管束模糊不清,幼苗细胞质壁分离,叶绿体萎缩坏死,细胞核变形。研究表明,高浓度胡桃醌通过抑制受体小麦保护酶活性,加重膜脂过氧化程度,导致幼根、幼苗细胞结构的破坏,从而产生化感效应,且化感效应随浓度的增加不断增强。

Allelopathic Effects of Juglone on the Growth of Wheat Seedlings and Seed Germination

By method of Petri dish bioassay and biochemical analysis,the allelopathy mechanism of juglone were researched through effect-testing of juglone with different concentrations on seed germination and seedling growth of wheat.The results indicated that:(1)The low concentration(4 and 20 μmol·L-1) of juglone has high hasten effect on seed germination and seedling growth,which promoted the content of soluble protein and decreased the content of malondiadehyde(MDA) and the activity of superoxide dismutase(SOD).(2)With the concentration of juglone increasing(100～1 250 μmol·L-1),the activity of SOD of wheat was firstly increased and then decreased,and the content of MDA was getting higher.Besides,the α-amylase activity and the content of soluble protein and the relative water content were declined.(3)Under 1 250 μmol·L-1 juglone treatment,cells were degraded gradually,cell structure was in disorder and had a severe twist,vascular bundle was disappeared,cell walls had a twist with slight plasmolysis,chloroplast was damaged and reduced,while cell nucleus were damaged.In summary,with the increasing concentration of juglone,the allelopathy effect was raised.The degree of membrane lipid peroxidation was strengthened and the activities of protective enzymes and seed germination and seedling growth were inhibited.