不同生长期加拿大蓬挥发油对蚕豆保卫细胞的毒性效应

为探讨入侵植物加拿大蓬(Erigeron canadensis L.)的化感作用机制,以蚕豆(Vicia faba L.)叶下表皮为材料,研究了营养期和生殖期加拿大蓬挥发油各1μL、2μL、3μL、4μL、5μL分别处理保卫细胞10 min、20 min、30 min后产生的毒性效应。结果表明:挥发油处理后保卫细胞大量死亡,核形态发生较大改变;细胞死亡率和核异常率显著上升(p0.05),与处理剂量和时间呈正相关(p0.01);营养期挥发油处理后细胞的死亡率和核异常率总体高于生殖期;加入泛Caspase抑制剂后,细胞死亡率显著降低(p0.05)。研究表明,加拿大蓬挥发油引起的保卫细胞死亡为Caspase依赖性的细胞凋亡,营养期挥发油的化感胁迫效应比生殖期更强。结合GC-MS分析可见,不同生长期加拿大蓬挥发油毒性的差异可能与其化感物质的组成和含量差异有关。

Toxic effect of the volatile oil from the different growth periods of Erigeron canadensis L.on the guard cells of Vicia faba L.

The present paper is to be engaged in a study of the toxic effects of its volatile oil extracted in its different growth periods on the guard cells from the leaves under epidermis of the broad bean (Vicia faba L.) in hoping to identify and clarify the allelopathy mechanism of the intrusive plant known as Erigeron canadensis L.In the research process,we have managed to treat the guard cells individually and separately by using the volatile oil in small amounts of 1 μL,2 μL,3 μL,4 μL,5 μL from E.canadensis in the vegetative period and the reproductive period for 10 min,20 min and 30 min.The results of our experiments show that the volatile oil may lead to the cell deaths in large numbers,as well as great changes of the morphology of the nucleus.As a result,the cell death rate and the abnormal changing rate of the nuclei in the treated groups have been found significantly aggravated (p ＜ 0.05),which is noticeably in the positive correlation with the dose and time for the volatile oil (p ＜ 0.01) treating.For instance,the mortality and nuclear abnormality rates of the group treated by the volatile oil in vegetative period turn out to be much higher than those in reproductive period,especially for the group treated with 5 μL volatile oil in the vegetative period for 30 main,whose worst toxic effect may have been so high as to 89.44％ cell death rate and 82.77％ nuclear aberration rate.However,by adding to the Caspase inhibitor Z-VAD-FMK,it would be possible to reduce the mortality rate remarkably (p ＜ 0.05) by being treated with E.canadensis.Thus,the results tend to suggest that the volatile oil from E.canadensis can induce the Caspase dependent apoptosis in the guard cells of Vicia faba,whereas the allelopathic stress effect of the said oil in the vegetative period proves stronger than that in the reproductive period.The GC-MS analysis results also indicate that the main component of the volatile oil from vegetative period E.canadensis turn out to be trans-β-farnesene,caryophyllene and (-)-spathulenol,with its main component from reproductive period of E.canadensis being d-limonene,caryophyllene oxide and (-)-spathulenol,which may imply that the difference in the toxic effect of the volatile oil from E.cantadensis in different growth periods may result from the composition and content concentration rates of the allelopathic compounds for the different growing periods.