Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
Physiol Plant. 2022 Mar;174(2):e13660. doi: 10.1111/ppl.13660.
Elevated CO (eCO ) has the potential to increase plant biomass while decreasing water demand due to enhanced water-use efficiency (WUE), which interacts with nutritional status. Carbon isotope discrimination (Δ C) has been shown to be a valid proxy for estimating WUE; however, its validity is uncertain for plants in an environment where the interaction between CO and nutrition strongly affects WUE. Using a single potato cultivar (Irish Cobbler), we examined its validity through three independent trials with varying levels of P, N, or K (Trial P, N, and K, respectively) in growth chambers at two CO concentrations. WUE at the plant level varied with CO conditions and nutrient supply rates. Plant biomass was positively regressed against WUE in Trials P and K, and water use in Trial N. WUE was negatively regressed against Δ C across various nutrient supply rates within each CO environment. However, the relationship between WUE and Δ C was altered with CO enrichment by elevating the intercept along the y-axis (WUE) without affecting the slope, implying the involvement of isotopic discrimination in respiration or photorespiration. These results suggest that Δ C can be used to estimate WUE across various nutrient statuses, not only at the current CO but also at eCO when the comparisons are made within each CO condition.
升高的 CO（eCO）有可能增加植物生物量，同时由于增强的水分利用效率（WUE）而减少水的需求，这与营养状况相互作用。碳同位素分馏（ΔC）已被证明是估计 WUE 的有效替代物；然而，当 CO 和营养之间的相互作用强烈影响 WUE 时，其对植物的有效性尚不确定。使用单一的马铃薯品种（爱尔兰 cobbler），我们通过在两个 CO 浓度下的生长室中进行的三个具有不同 P、N 或 K 水平的独立试验（分别为试验 P、N 和 K）来检验其有效性。在不同的 CO 条件和养分供应速率下，植物水平的 WUE 有所不同。在试验 P 和 K 中，植物生物量与 WUE 呈正相关，而在试验 N 中与水的使用量呈正相关。在每个 CO 环境中，随着各种养分供应速率的增加，WUE 与 ΔC 呈负相关。然而，当在每个 CO 条件内进行比较时，CO 富集会改变 WUE 与 ΔC 之间的关系，即沿着 y 轴（WUE）提高截距而不影响斜率，这意味着同位素分馏可能参与了呼吸或光呼吸。这些结果表明，ΔC 可用于估计各种养分状况下的 WUE，不仅在当前 CO 下，而且在 eCO 下也是如此。
Zotero 插件