汞胁迫对辣椒种子萌发和幼苗生长的影响

Effects of Hg^(2+) Stress on Seed Germination and Seedling Growth of Capsicum annuum L.

[目的]为研究Hg2+对植物的毒害机理提供理论依据。[方法]用不同浓度(0、0.5、1.0、5.0、10.0、25.0、50.0μmol/L)氯化汞溶液分别对辣椒种子进行浸种处理,通过种子发芽试验和生长试验,研究Hg2+胁迫对辣椒种子的发芽率、胚轴和胚根长度及幼苗中叶绿素、丙二醛和游离脯氨酸的含量以及过氧化物酶活性(POD)的影响。[结果]随Hg2+浓度的增加,Hg2+对辣椒种子萌发、胚轴和胚根生长的抑制作用增强,幼苗叶片内的叶绿素含量降低,丙二醛和游离脯氨酸的含量明显增加,POD活性呈先上升后下降的趋势,POD活性在Hg2+浓度为25.0μmol/L时最高。[结论]经5.0μmol/L氯化汞溶液浸种后,辣椒种子的萌发及其胚根、胚轴生长受到抑制。高浓度Hg2+胁迫下,叶绿素含量降低直接影响了叶片的光合作用,会降低植物株高和生物量,甚至导致死亡。

[Objective] The research aimed to provide the theoretical basis for studying the toxicity mechanism of Hg^2＋ to plants. [Method] The seeds of Capsicum annuum L. were soaked with different concentrations （0,0.5,1.0, 5.0, 10.0, 25.0, 50.0 μmol/L ）of mercuric chloride solution. In seed germination test and growth test, the effects of Hg^2＋ stress on seed germination rate,the length of hypocotyl and radicle,the contents of chlorophyll, malondialdehyde （MDA） and free proline, and peroxidase （POD） activity in C. annuum were studied. [Result] With the increasing of Hg^2＋ concentration, the inhibitory actions of Hg^2＋ on the seed germination, the growth of hypocotyl and radicle in C. annuum were strengthened, the chlorophyll content in seedling leaves were decreased, the contents of MDA and free proline were significantly increased, the activity of POD showed a trend of first increasing and then decreasing, being highest at 25.0 μmol/L Hg^2＋. [Conclusion] After being soaked with 5.0 μmol/L mercuric chloride solution, the seed germination, the growth of hypoeotyl and radicle in C. annuum were inhibited. Under the stress with high - concentration Hg^2＋, the chlorophyll content was decreased and the photosynthesis of leaves in C. annuum was directly affected, which would decrease plant height and biomass, even lead to death.