通过外源MeJA抑制H_2O_2积累提高烟草的耐冷性

Exogenous MeJA improves cold tolerance of tobacco by inhibiting H_2O_2 accumulation

茉莉酸甲酯(MeJA)是可参与多种生理生化过程的激发子,为探究外源MeJA对低温环境下烟草幼苗的影响,以烟草品种"豫烟10号"为材料,在其六叶一心时用4个不同浓度(1、10、100和1000μmol L^(–1) MeJA)进行喷施处理3d后,再进行低温处理,同时以正常温度和低温处理作为阳性和阴性对照。分析各处理的长势指标、相对电解质渗透率、光合色素含量、抗氧化酶活性以及激素含量。结果表明:在10μmol L^(–1)茉莉酸甲酯处理下能降低低温对烟草幼苗的损伤。然后在材料和时期不变的情况下,进行DPI、10μmol L^(–1) MeJA以及DPI+MeJA处理以低温处理为对照,测定了H_2O_2、O^(2–)、CAT、MDA以及ASA-GSH循环的含量。证明在外源茉莉酸甲酯协同低温的处理下,烟草植株中的H_2O_2主要作为毒害分子而非第二信使存在。

Methyl jasmonate(MeJA)is an elicitor evolving in a variety of physiological and biochemical processes.To explore the effects of exogenous MeJA on tobacco seedlings under low temperature conditions,we used the tobacco variety“Yuyan 10”and sprayed four concentrations(1,10,100,1000 μmol L^–1)of MeJA for 3 days on plants.Under low temperature with the treatment under normal temperature as positive and that under low temperature on negative control.The growth indicators,relative electrolyte permeability,photosynthetic pigment content,antioxidant enzyme activity and hormone content of each treatment were measured,showing that the treatment with 10 μmol L–1 methyl jasmonate could reduce the damage of tobacco seedlings caused by low temperature.The effect of H2O2 was then verified by applications of DPI,10 μmol L^–1 MeJA,and DPI+MeJA with the same material and growth period,while low temperature treatment was used as a control.The contents of H2O2,O^2–,CAT,MDA,and ASA-GSH cycle were determined.In conclusion,H2O2 in tobacco plants mainly exists as a poison molecule instead of a second messenger under the treatment of exogenous methyl jasmonate combined with low temperature.