Summary Early stress detection of crops requires a thorough understanding of the signals showing the very first symptoms of the alterations in the photosynthetic light reactions. Detection of the activation of the regulated heat dissipation mechanism is crucial to complement passively induced fluorescence to resolve ambuiguities in energy partitioning. Using leaf spectroscopy, we evaluated the capability of pigment spectral unmixing to calculate the fluorescence quantum efficiency (FQE) and simultaneously retrieve fast absorption changes in a drought and nitrogen deficiency experiment with tomato. In addition, active fluorescence measurements and pigment analyses of xanthophylls, carotenes and chlorophylls were conducted. We observed notable responses in noninvasive proximal sensing‐retrieved FQE values under stress, but as expected, these alone were not enough to identify the constraints in photosynthetic efficiency. Reflectance‐based detection of the 535‐nm peak absorption change was able to complement FQE and indicate the activation of regulated heat dissipation for both stress treatments under growing light conditions. However, further complexity in the light harvesting energy regulation needs to be accounted for when considering additional light stress. Our results underscore the potential of complementary in vivo quantitative spectroscopy‐based products in the early and nondestructive stress diagnosis of plants, marking the path for further applications.

中文翻译：

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与调节散热机制相关的光谱反射率变化的体内检测补充了早期应力诊断中的荧光量子效率


摘要 作物的早期胁迫检测需要彻底了解显示光合光反应改变最初症状的信号。检测调节散热机制的激活对于补充被动诱导荧光以解决能量分配中的湿度至关重要。使用叶光谱学，我们评估了色素光谱解混计算荧光量子效率 （FQE） 的能力，并在番茄的干旱和氮缺乏实验中同时检索快速吸收变化。此外，还进行了叶黄素、胡萝卜素和叶绿素的主动荧光测量和色素分析。我们在压力下观察到无创近端传感检索的 FQE 值的显着反应，但正如预期的那样，仅凭这些不足以确定光合作用效率的限制。基于反射率的 535 nm 峰值吸收变化检测能够补充 FQE，并表明在生长光条件下两种应力处理的调节散热被激活。然而，在考虑额外的光应力时，需要考虑光收集能量调节的进一步复杂性。我们的结果强调了基于互补体内定量光谱的产品在植物的早期和无损胁迫诊断中的潜力，为进一步的应用指明了道路。