土荆芥挥发油对豌豆根边缘细胞的诱导和胁迫作用

Induced and stress effects of volatile oil from Chenopodium ambrosioide L.on root border cells of pea

为探讨化感胁迫对根边缘细胞的诱导效应,实验采用悬空气培养法培养豌豆(Pisum sativum L.)露白种子,在保留根边缘细胞和去除根边缘细胞状态下,选取相对根长、根边缘细胞数量及死亡率、果胶甲基酯酶(PME)等指标研究了豌豆根边缘细胞对不同剂量土荆芥挥发油化感作用的响应。结果表明:1)与对照相比,随着挥发油处理剂量增加,根的伸长被显著抑制(P<0.05)。2)每个处理时间内,随着土荆芥挥发油剂量增加,根边缘细胞数量整体表现出先增加后减少的趋势,在低剂量2μL处理中达极大值。3)土荆芥挥发油诱导豌豆根边缘细胞死亡,随着处理时间的延长和处理剂量的增加,这种毒害效应程度加剧,除去边缘细胞实验组中10μL挥发油处理24 h时,根边缘细胞死亡率达到100%。在较低剂量挥发油作用下,保留根边缘细胞组的根边缘细胞死亡率高于去除根边缘细胞组,而在高剂量挥发油处理情况则相反。4)在同一处理时间,随挥发油剂量增加,各处理组PME活性持续升高,去处边缘细胞组处理24 h后不同剂量处理皆显著高于对照,而根边缘细胞数量总体表现先增加后减少。综合以上结果,保留根边缘细胞的根尖根边缘细胞的数量减少量较少,说明根边缘细胞能缓解土荆芥挥发油的化感胁迫;去除根边缘细胞组的PME活性升高较多,表明土荆芥化感胁迫诱导了根边缘细胞的产生。

The aim of this study was to investigate the inductive effect of root border cells （RBCs） of pea （Pisum sativum L.） under allelopathy related stress. Aeroponic method was used to cultivate the germinated pea seeds. Two types of samples were prepared, normal seed （control） and ones without root border cell （experimental group）. Physiological indices, including relative root length, the number and mortality of RBCs, as well as the pectin methylesterase （PME） level, were used to evaluate the response of pea RBCs to different doses of volatile oil from Chenopodium ambrosioides L. The results showed that： 1） compared with the control, root elongation was inhibited significantly （P〈0.05） with the increasing of volatile oil dosage used in treatment; 2） with increased dosage of volatile Oil from C. ambrosioides L., the number of RBCs increases firstly and then decreases at different process-time. Therein, RBCs amount reached a maximum when low-dose of was added （2 μL）; 3） Volatile oil from C. Ambrosioides L. could contribute to the death of RBC. Both prolonged process-time and increased dosage could aggravate the toxic effect. After treatment for 24 h using 10μL volatile oil, the death rate reached 100% in the experimental group （removing root border ceils）. On the contrary, with the function of low concentration of volatile oil, the mortality of control was higher than experimental group. 4） During the same treatment time, the activities of PME in different experimental groups increased with the increasing of volatile oil concentration. And PME levels of all experimental groups are significantly higher than the control after treating for 24 h. In conclusion, our study revealed that RBCs plays a protective role in allelopathy related stress induced by C. ambrosioides L. On the other hand, allelopathy contributes in the generation of RBCs.