薯瘟菌对甘薯叶片光合特性及叶绿体结构的影响

Photosynthetic Characteristics and Chloroplast Ultrastructure of Sweet Potato Leaves Infected by Ralstonia solanacearum

摘要:

为探讨甘薯(Dioscorea esculenta)被薯瘟菌(Ralstonia solanacearum)侵染后的响应,以抗病品种‘湘薯75-55'和感病品种‘胜利百号'为材料,对甘薯叶片的光合特性和叶绿体结构进行了研究。结果表明,薯瘟菌侵染后,‘胜利百号'叶片的细胞膜透性(MP)明显增大,叶绿素(Chl)含量下降,净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)下降,胞间二氧化碳浓度(Ci)和内源ABA 含量急剧升高,且细胞膜完整性被破坏,叶绿体数目减少、膨胀模糊、基粒片层松散解体以及淀粉粒变小;而‘湘薯75-55'的各个指标变化不大,细胞膜结构完整,叶绿体基粒片层排列整齐。因此,薯瘟菌侵染后不同抗病品种甘薯叶片在光合特性和叶绿体结构上表现出显著的差异。

Abstract:

In order to understand the response of sweet potato (Dioscorea esculenta) to Ralstonia solanacearum, two varieties, including resistant ‘Xiangshu 75-55' and sensitive ‘Shenglibaihao’, were used as materials, the changes in photosynthetic characteristics, abscisic acid (ABA) content and chloroplast ultrastructure were studied after infected by R. solanacearum. The results showed that the membrane permeability (MP), intercellular CO₂ concentration (Ci) and endogenous ABA content in ‘Shenglibaihao’ infected by R. solanacearum increased markedly, but chlorophyll (Chl) content, net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) obviously decreased. Besides, the integrity of chloroplast membrane system was damaged, the number of chloroplast decreased, and expansion to collapse, the grana lamella loosed and disintegrated, and starch grains got smaller in ‘Shenglibaihao’ leaves affected. In contrast, for ‘Xiangshu 75-55', the changes in the related physiological indexes were not different significantly, and the plasma membrane and lamellar still kept integration. Therefore, there were distinct differences in the PMP, Chl content, ABA content, Pn and chloroplast structure between the two sweet potato varieties with different disease-resistance.