Dpto. Ciencias del Medio Natural, Universidad Pública de Navarra, Campus de Arrosadía, E-31192, Mutilva Baja, Spain.
Instituto de Agrobiotecnología (IdAB), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Campus de Arrosadía, E-31192, Mutilva Baja, Spain.
Physiol Plant. 2016 Sep;158(1):65-79. doi: 10.1111/ppl.12417. Epub 2016 Mar 16.
Although shoot N depletion in plants exposed to elevated [CO2 ] has already been reported on several occasions, some uncertainty remains about the mechanisms involved. This study illustrates (1) the importance of characterizing root-shoot interactions and (2) the physiological, biochemical and gene expression mechanisms adopted by nitrate-fed Arabidopsis thaliana plants grown under elevated [CO2 ]. Elevated [CO2 ] increases biomass and photosynthetic rates; nevertheless, the decline in total soluble protein, Rubisco and leaf N concentrations revealed a general decrease in leaf N availability. A transcriptomic approach (conducted at the root and shoot level) revealed that exposure to 800 ppm [CO2 ] induced the expression of genes involved in the transport of nitrate and mineral elements. Leaf N and mineral status revealed that N assimilation into proteins was constrained under elevated [CO2 ]. Moreover, this study also highlights how elevated [CO2 ] induced the reorganization of nitrate assimilation between tissues; root nitrogen assimilation was favored over leaf assimilation to offset the decline in nitrogen metabolism in the leaves of plants exposed to elevated [CO2 ].
尽管已经多次报道过暴露在高浓度[CO2]下的植物中氮素的减少，但其中涉及的机制仍存在一些不确定性。本研究说明了（1）描述根-茎相互作用的重要性，以及（2）在高浓度[CO2]下生长的硝酸盐供应的拟南芥植物所采用的生理、生化和基因表达机制。高浓度[CO2]增加了生物量和光合速率；然而，总可溶性蛋白、Rubisco 和叶片氮浓度的下降表明叶片氮供应普遍减少。转录组学方法（在根和茎水平上进行）表明，暴露于 800 ppm [CO2] 诱导了参与硝酸盐和矿物质元素运输的基因的表达。叶片氮和矿物质状况表明，氮同化为蛋白质受到高浓度[CO2]的限制。此外，本研究还强调了高浓度[CO2]如何诱导组织间硝酸盐同化的重新组织；根氮同化优先于叶片同化，以抵消暴露于高浓度[CO2]下的植物叶片中氮代谢的下降。
