土荆芥化感胁迫下蚕豆叶绿体超微结构和光合关键基因表达的变化

Effect of Allelochemical Stress from Chenopodium ambrosioides L.on Chloroplast Ultrastructure and Photosynthetic Key Gene Expression in Leaves of Vicia faba Seedlings

【目的】叶绿体结构的完整性和光合作用关键基因表达正常在光合作用中起着重要作用。为了深入探讨土荆芥化感作用机制。【方法】采用透射电镜技术和RT-PCR技术,对土荆芥挥发油及其主要成分α-萜品烯和对伞花素对蚕豆幼苗叶片叶绿体超微结构和4个光合关键基因的影响进行了研究。【结果】土荆芥挥发油及其主要成分处理导致蚕豆叶片叶绿体超微结构受损,叶绿体脱离细胞壁散乱分布于细胞中央,结构紊乱,表现为肿胀、膜结构受损明显,叶绿体内部基质不均匀、基粒类囊体排列紊乱、淀粉粒消失、片层扭曲且排列松散;在光合作用过程的关键基因核酮糖羧化酶基因(Rbcs-3C)、光系统ⅡCP47蛋白基因(PsbB)、ATP合成酶β亚基基因(beta)、质体蓝素基因(PetE)的相对表达量发生了不同程度的变化。其中,挥发油处理组中4个基因均上调;对伞花素处理组Rbcs-3C和PsbB下调,beta和PetE上调;α-萜品烯处理组的PsbB下降,其他3个基因上调; 3个处理的化感综合效应由大到小依次为挥发油、α-萜品烯和对伞花素。【结论】破坏叶绿体超微结构、干扰光合关键基因表达是土荆芥化感胁迫的机制之一,土荆芥挥发油的不同成分对受体植物的化感作用具有协同性。

【Objective】The integrity of chloroplast structure and the normal expression of key genes in photosynthesis play an important role in photosynthesis.【Method】This paper researched the influence of the volatile oil of Chenopodium ambrosioides L.,and its two main components(α-terpinene and cymene)on chloroplast ultrastructure and 4 key photosynthetic genes in leaves of Vicia faba seedlings by the technology of TEM and RT-PCR,and in order to intensively study the allelopathic mechanism of C.ambrosioides.【Result】The results showed that the volatile oil,α-terpinene and cymene of C.ambrosioides damaged the ultrastructure of chloroplast in V.faba leaves,and the chloroplast was disorganized with tumid and damaged membrane structure,heterogeneous substrate,disorganized granum-thylakoid,disappeared starch grain and twisty incompact lamella scattered from the wall to the center of the cell.The relative expression of Ribulose carboxylase gene(Rbcs-3C),optical systemⅡCP47 protein gene(PsbB),ATP synthetase beta subunit gene(beta)and plasmid blue pigment genes(PetE)were changed in different extent during photosynthesis.The volatile oil of C.ambrosioides increased the relative expression of these 4 genes.Cymene decreased the relative expression of Rbcs-3C and PsbB,and increased the relative expression of beta and PetE.Theα-terpinene decreased the relative expression of PsbB and increased others.The allelopathic synthesis effect of three treatments on these gene expressions from most significant to least significant were volatile oil,α-terpinene and cymene.【Conclusion】These results indicated that the damage of chloroplast ultrastructure and interference of photosynthetic key gene expression were one part of the allelopathic mechanism of C.ambrosioides and different components of the volatile oil from C.ambrosioides had a synergistic effect in allelopathy.