Quantitative evidence of underestimated nitrogen rhizodeposition using 15N split-root labeling during spring wheat developmental period
Quantitative evidence of underestimated nitrogen rhizodeposition using 15N split-root labeling during spring wheat developmental period
复制标题
使用 N-15 分根标记在春小麦发育期间低估根际氮沉积的定量证据
DOI：
10.1016/j.catena.2021.105618
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发表时间：
2021-07-29
期刊：
影响因子：
6.2
通讯作者：
Han, Shijie
中科院分区：
文献类型：
--
作者：
Cao, Yanhong;Sun, Xinchao;Han, Shijie
根际沉积氮素的准确定量分析是研究植物体内氮素储存和植物-土壤系统氮素平衡的关键。然而，仍然存在不确定性的估计NdfR的N-15标记的植物与分根技术使用同位素比的方法和同位素质量平衡的方法。在这里，我们检查了从春小麦（小麦L.）的N-15-尿素（99原子%）标记中估计NdfR的两种计算方法。在盆栽试验中使用分根技术对植物生长的影响，并评估了其潜在偏倚的原因。结果表明，在整个生育期内，NdfR的总量为5.3- 9.8mg/株，占植株总氮的19.9-26.3%。在标记后的抽穗期和灌浆期，NdfR的量（5.3和6.6毫克植物（-1），分别）显着低于那些（7.1和7.8毫克植物（-1），分别）使用同位素质量平衡法，由于土壤氮素损失和N-15的分布不均匀。然而，在标记后的成熟阶段，两种方法之间NdfR量的差异消失（分别为9.8和9.6 mg植物（-1））。这表明同位素比值法低估了植物发育期间NdfR的量，而这两种方法都可以用来量化植物成熟时NdfR的量。
Accurate quantification of nitrogen (N) derived from rhizodeposition (NdfR) is crucial to assess N stored in plants and the total N balance in plant-soil systems. However, there remains uncertainty in the estimates of NdfR for N-15-labeled plants with the split-root technique using the isotope ratio approach and the isotope mass balance approach. Here, we examined the two calculation approaches that estimate NdfR from N-15-urea (99 atom%) labeling of spring wheat (Triticum aestivum L.) using the split-root technique in a pot experiment over plant growth, and assessed the causative factors of their potential bias. The results showed that independent of the approach, the total amount of NdfR was 5.3-9.8 mg plant(-1) and contributed up to 19.9-26.3% of total plant N throughout the growth period. At the heading and filling stages after labeling, the amounts of NdfR using the isotope ratio approach (5.3 and 6.6 mg plant(-1), respectively) were significantly lower than those (7.1 and 7.8 mg plant(-1), respectively) using the isotope mass balance approach, due to soil N losses and an uneven distribution of N-15. At the ripening stage after labeling, however, the differences in the amount of NdfR between the two approaches disappeared (9.8 and 9.6 mg plant(-1), respectively). This indicated that the isotope ratio approach underestimates the amount of NdfR during the plant developmental period, while both approaches can be used to quantify the amount of NdfR at plant maturity.