Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Science International Islamic University Islamabad, Pakistan.
Sci Total Environ. 2018 Dec 1;643:357-366. doi: 10.1016/j.scitotenv.2018.06.131. Epub 2018 Jun 22.
Elevated CO and use of endophytic microorganisms have been considered as efficient and novel ways to improve phytoextraction efficiency. However, the interactive effects of elevated CO and endophytes on hyperaccumulator is poorly understood. In this study, a hydroponics experiment was conducted to investigate the combined effect of elevated CO (eCO) and inoculation with endophyte SaMR12 (ES) on the photosynthetic characteristics and cadmium (Cd) accumulation in hyperaccumulator Sedum alfredii. The results showed that eCO × ES interaction promoted the growth of S. alfredii, shoot and root biomass net increment were increased by 264.7 and 392.3%, respectively, as compared with plants grown in ambient CO (aCO). The interaction of eCO and ES significantly (P < 0.05) increased chlorophyll content (53.2%), Pn (111.6%), Pn (59.8%), AQY (65.1%), and Lsp (28.8%), but reduced Gs, Tr, Rd, and Lcp. Increased photosynthetic efficiency was associated with higher activities of rubisco, Ca-ATPase, and Mg-ATPase, and linked with over-expression of two photosystem related genes (SaPsbS and SaLhcb2). PS II activities were significantly (P < 0.05) enhanced with Fv/Fm and Φ(II) increased by 12.3 and 13.0%, respectively, compared with plants grown in aCO. In addition, the net uptake of Cd in the shoot and root tissue of S. alfredii grown in eCO × ES treatment was increased by 260.7 and 434.9%, respectively, due to increased expression of SaHMA2 and SaCAX2 Cd transporter genes. Our results suggest that eCO × ES can promote the growth of S. alfredii due to increased photosynthetic efficiency, and improve Cd accumulation and showed considerable potential of improving the phytoextraction ability of Cd by S. alfredii.
升高的 CO 和内生微生物的利用被认为是提高植物提取效率的有效和新颖的方法。然而，升高的 CO 和内生菌对超积累植物的相互作用还了解甚少。本研究通过水培实验，研究了升高的 CO (eCO) 和内生菌 SaMR12（ES）接种对超积累植物垂盆草光合作用特性和镉（Cd）积累的综合影响。结果表明，eCO×ES 相互作用促进了垂盆草的生长，与在环境 CO (aCO) 中生长的植物相比，地上部和根生物量净增量分别增加了 264.7%和 392.3%。eCO 和 ES 的相互作用显著（P<0.05）增加了叶绿素含量（53.2%）、净光合速率（Pn）（111.6%）、Pn（59.8%）、AQY（65.1%）和 Lsp（28.8%），但降低了胞间 CO2 浓度（Gs）、蒸腾速率（Tr）、气孔导度（Rd）和叶水导度（Lcp）。光合效率的提高与 Rubisco、Ca-ATPase 和 Mg-ATPase 活性的升高有关，与两个光系统相关基因（SaPsbS 和 SaLhcb2）的过表达有关。与在 aCO 中生长的植物相比，PS II 活性显著（P<0.05）增强，Fv/Fm 和 Φ(II)分别增加了 12.3%和 13.0%。此外，由于 SaHMA2 和 SaCAX2 Cd 转运基因表达增加，eCO×ES 处理中垂盆草地上部和根部组织对 Cd 的净吸收分别增加了 260.7%和 434.9%。研究结果表明，eCO×ES 可以通过提高光合作用效率来促进垂盆草的生长，并提高 Cd 的积累，显示出提高 Cd 超积累植物垂盆草植物提取能力的巨大潜力。
