Shokat Sajid, Liu Fulai, Großkinsky Dominik K
Section for Crop Science, Department of Plant and Environmental Sciences, University of Copenhagen, Højbakkegård Allé 13, 2630 Taastrup, Denmark.
Wheat Breeding Group, Plant Breeding and Genetics Division, Nuclear Institute for Agriculture and Biology, Faisalabad 38000, Pakistan.
Plants (Basel). 2024 Oct 21;13(20):2942. doi: 10.3390/plants13202942.
This study aimed to analyze the combined impact of CO and drought stress at the flowering stage on carbon (C), nitrogen (N), and CN ratios in leaves, stem, and grains of bread wheat. Six diverse bread wheat genotypes, comprised of two commercial checks, two landraces, and two synthetics derivatives, were grown at two levels of CO, i.e., 400 ppm and 800 ppm, and drought stress was imposed at the flowering stage through progressive soil drying. Stem, leaf, and grain samples were taken at maturity and concentrations of C and N were determined. Our results indicate that the threshold value of fraction of transpirable soil water (C) at which it diverges towards closure of stomata was different among genotypes and a higher range of values was estimated under elevated CO. Drought significantly increased C levels in leaves and N levels in grains but decreased N levels in leaves, which increased CN ratios in leaves. In contrast, drought significantly reduced CN ratios in grains. Genotypes differed significantly in N content in grains, where the landrace derivative L maintained the highest N content. Moreover, pronounced changes in leaf N and CN ratios were induced by the combination of elevated CO and drought stress. Additionally, combined correlation and biplot analyses indicate a strong positive association of grain CN (GCN) with grain number, weight, and grain yield. These effects possibly interact with drought to strongly interfere with the impact of elevated CO. The differential performance of the tested genotypes shows that selection of appropriate germplasm is essential to maintain agricultural production.
本研究旨在分析开花期一氧化碳（CO）和干旱胁迫对面包小麦叶片、茎和籽粒中碳（C）、氮（N）及碳氮比的综合影响。选用六个不同的面包小麦基因型，包括两个商业对照品种、两个地方品种和两个人工合成衍生品种，在两种CO水平下种植，即400 ppm和800 ppm，并在开花期通过逐步干燥土壤施加干旱胁迫。在成熟期采集茎、叶和籽粒样本，测定C和N的含量。我们的结果表明，不同基因型间气孔关闭时的可蒸腾土壤水分（C）阈值不同，在CO浓度升高时估计值范围更高。干旱显著增加了叶片中的C含量和籽粒中的N含量，但降低了叶片中的N含量，从而增加了叶片中的碳氮比。相反，干旱显著降低了籽粒中的碳氮比。不同基因型的籽粒N含量差异显著，地方品种衍生品种L的N含量最高。此外，CO浓度升高和干旱胁迫共同作用诱导了叶片N和碳氮比的显著变化。此外，相关性和双标图分析表明，籽粒碳氮比（GCN）与籽粒数量、重量和籽粒产量呈强正相关。这些效应可能与干旱相互作用，强烈干扰CO浓度升高的影响。所测试基因型的不同表现表明，选择合适的种质对于维持农业生产至关重要。
