蚕豆幼苗光合特性对土荆芥挥发性物质胁迫的响应

Response of photosynthetic characteristics of Vicia faba seedlings to volatile allelochemical stress from Chenopodium ambrosioides

关键词:  土荆芥, 化感胁迫, 光合特性, α-萜品烯, 对伞花素

Key words:   Chenopodium ambrosioides, allelochemical stress, photosynthetic characteristics, α-terpinene, cymene

摘要:

以蚕豆(Vicia faba)为受体,采用盆栽试验评价了入侵植物土荆芥(Chenopodium ambrosioides)挥发油及其两个主要成分α-萜品烯和对伞花素对受体光合特性的影响。结果表明:土荆芥挥发油及其两个主要成分不同程度地影响了蚕豆叶片的特性。挥发油处理显著降低了净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)、最大光化学效率(F_v/F_m)、实际光化学效率(ΦPSⅡ)和叶绿素含量,但增加了胞间CO₂浓度(C_i),这种效应表现为剂量和时间双重效应,高剂量挥发油处理的这种效应是不可逆的; 与对照相比,α-萜品烯处理组的P_n、F_v/F_m和ΦPSⅡ降低,C_i、G_s和T_r上升,停止处理后,各参数均趋于对照水平; 整体来看,对伞花素对蚕豆幼苗的光合特性影响不大。上述研究结果说明,土荆芥化感胁迫对受体光合特性的影响是诸多化感物质协同作用的结果,并非由单一组分决定。

Abstract:

Pot experiment was conducted to evaluate the effect of volatile oil from an invasive plant, Chenopodium ambrosioides and its two main components α-terpene and cymene on the photosynthetic characteristics of Vicia faba seedlings. The results showed that the volatile oil treatment significantly reduced the net photosynthetic rate(P_n), stomatal conductance(G_s), transpiration rate(T_r), maximum photochemical efficiency(F_v/F_m), actual photochemical efficiency(ΦPS Ⅱ)and total chlorophyll content. However, it increased the concentration of intercellular CO₂(C_i), which was the dual effect of dose and time, and the effect of high dosed volatile oil treatment was irreversible. Compared with the control group, α-terpene treatment reduced P_n, F_v/F_m and ΦPS Ⅱ, increased C_i, G_s and T_r, and all the parameters were gradually approaching to the control level after stopping treatment. However, the effects of cymene on photosynthetic characteristics of Vicia faba seedlings were not significant. These results suggested that the volatile allelochemical stress from Chenopodium ambrosioides on photosynthesis of receptor plants was due to the the synergistic effect of many allelochemicals, instead of a single component.