Sun Dawei, Xu Haixia, Weng Haiyong, Zhou Weijun, Liang Yan, Dong Xiaoya, He Yong, Cen Haiyan
College of Biosystems Engineering and Food Science, and State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China.
Key Laboratory of Spectroscopy Sensing, Ministry of Agriculture and Rural Affairs, Hangzhou, China.
J Exp Bot. 2020 Oct 22;71(20):6429-6443. doi: 10.1093/jxb/eraa372.
Nitrogen (N) fertilizer maximizes the growth of oilseed rape (Brassica napus L.) by improving photosynthetic performance. Elucidating the dynamic relationship between fluorescence and plant N status could provide a non-destructive diagnosis of N status and the breeding of N-efficient cultivars. The aim of this study was to explore the impacts of different N treatments on photosynthesis at a spatial-temporal scale and to evaluate the performance of three fluorescence techniques for the diagnosis of N status. One-way ANOVA and linear discriminant analysis were applied to analyze fluorescence data acquired by a continuous excitation chlorophyll fluorimeter (OJIP transient analysis), pulse amplitude-modulated chlorophyll fluorescence (PAM-ChlF), and multicolor fluorescence (MCF) imaging. The results showed that the maximum quantum efficiency of PSII photochemistry (Fv/Fm) and performance index for photosynthesis (PIABS) of bottom leaves were sensitive to N status at the bolting stage, whereas the red fluorescence/far-red fluorescence ratio of top leaves was sensitive at the early seedling stage. Although the classification of N treatments by the three techniques achieved comparable accuracies, MCF imaging showed the best potential for early diagnosis of N status in field phenotyping because it had the highest sensitivity in the top leaves, at the early seedling stage. The findings of this study could facilitate research on N management and the breeding of N-efficient cultivars.
氮肥通过改善光合性能使油菜（Brassica napus L.）生长最大化。阐明荧光与植物氮素状况之间的动态关系可为氮素状况的无损诊断及氮高效品种的选育提供依据。本研究旨在探讨不同施氮处理在时空尺度上对光合作用的影响，并评估三种荧光技术诊断氮素状况的性能。采用单因素方差分析和线性判别分析对通过连续激发叶绿素荧光仪获取的荧光数据（OJIP瞬态分析）、脉冲幅度调制叶绿素荧光（PAM-ChlF）和多色荧光（MCF）成像进行分析。结果表明，在抽薹期，下部叶片的PSII光化学最大量子效率（Fv/Fm）和光合作用性能指数（PIABS）对氮素状况敏感，而在幼苗早期，上部叶片的红荧光/远红荧光比值敏感。虽然三种技术对施氮处理的分类准确率相当，但MCF成像在田间表型分析中对氮素状况早期诊断潜力最佳，因为它在幼苗早期对上部叶片具有最高的敏感性。本研究结果有助于氮肥管理研究及氮高效品种的选育。
