School of Agriculture, Ningxia University, Yinchuan, China.
PeerJ. 2022 Oct 31;10:e14273. doi: 10.7717/peerj.14273. eCollection 2022.
The nitrogen (N) and protein concentrations in plant tissues exposed to elevated CO (eCO) generally decline , such declines in forage grass composition are expected to have negative implications for the nutritional and economic value of grass. Plants require N for the production of a photosynthetically active canopy and storage proteins in the tissues, whose functionality will strongly influence productivity and quality. The objective of this study was to investigate whether eCO plus N-fertilization increases growth and N nutrition of , and the dependence of this improvement on the coordination between root and leaf development.
We analyzed from field-grown within the open-top chambers (OTCs) facility under two atmospheric CO (ambient, 400 ± 20 µmol mol, aCO, and elevated, 800 ± 20 µmol mol, eCO) and three N-fertigation treatments (control, low N-fertigation , and high N-fertigation) for two months.
Elevated CO plus N-fertigation strongly increased shoot and root biomass, and the nitrogen and protein concentrations of compared to those plants at aCO levels. Increased N content in leaves and reduced specific leaf area (SLA) at a high N supply could alleviate photosynthetic acclimation to eCO and drive the production of greater shoot biomass with the potential for higher photosynthesis, productivity, and nutritional quality. The increased root length (RL), the ratio of total aboveground N taken up per RL (TN/RL), stomatal conductance (Gs), and transpiration rate (Tr) contribute to the transpiration-driven mass flow of N, consequently increasing N uptake by roots. In addition, a smaller percentage of N remained as unassimilated nitrate ( ) under eCO, indicating that assimilation of into proteins was not inhibited by eCO. These findings imply that grass productivity and quality will enhance under anticipated elevated CO concentration when effective management measures of N-fertilization are employed.
暴露于升高的 CO 下的植物组织中的氮（N）和蛋白质浓度通常会下降，预计饲草组成的这种下降将对草的营养和经济价值产生负面影响。植物需要 N 来生产具有光合作用的冠层和组织中的储存蛋白质，其功能将强烈影响生产力和质量。本研究的目的是调查 eCO 加 N 施肥是否会增加 的生长和 N 营养，以及这种改善对根和叶发育之间协调的依赖性。
我们在开放顶室（OTC）设施内从田间生长的 进行了分析，该设施处于两种大气 CO（环境，400±20μmol mol，aCO 和升高，800±20μmol mol，eCO）和三种 N 施肥处理（对照，低 N 施肥和高 N 施肥）下进行了两个月。
与 aCO 水平下的植物相比，升高的 CO 加 N 施肥强烈增加了 的地上和地下生物量以及氮和蛋白质浓度。高 N 供应下叶片中增加的 N 含量和减少的比叶面积（SLA）可以缓解对 eCO 的光合作用适应，并促进产生更大的地上生物量，从而具有更高的光合作用、生产力和营养品质的潜力。增加的根长（RL）、每 RL 吸收的总地上 N 的比例（TN/RL）、气孔导度（Gs）和蒸腾速率（Tr）有助于蒸腾驱动的 N 质量流，从而增加了根对 N 的吸收。此外，eCO 下未同化硝酸盐（ ）的比例较小，这表明 eCO 不会抑制 同化到蛋白质中。这些发现表明，在预期的升高的 CO 浓度下，当采用有效的 N 施肥管理措施时，草的生产力和质量将提高。
