Data from: Reflections of stress: Ozone damage in broadleaf saplings can be identified from hyperspectral leaf reflectance

Tropospheric ozone causes widespread damage to vegetation, however,
monitoring of ozone-induced damage is usually reliant on manual leaf
inspection. Reflectance spectroscopy of vegetation can identify and detect
unique spectral signatures of different abiotic and biotic stressors. In
this study, we tested the use of hyperspectral leaf reflectance to detect
ozone stress in alder, beech, birch, crab apple, and oak saplings exposed
to five different ozone regimes (ranging from daily target maxima of 30ppb
ozone to 110ppb). Hyperspectral reflectance varied significantly between
ozone treatments, both in whole spectra analysis and when simplified to
representative components. Ozone damage had a multivariate impact on leaf
reflectance, underpinned by changes in pigment balance, water content, and
structural composition. Vegetation indices derived from reflectance which
characterised the visible green peak were able to differentiate between
ozone treatments. Iterative normalised difference spectral indices across
the hyperspectral wavelength range were correlated to visual damage scores
to identify significant wavelengths for ozone damage detection. We propose
a new Chronic Ozone Damage Index (COzDI), which characterises the
reflectance peak in the shortwave infrared region and is highly correlated
to ozone damage. These results pioneer hyperspectral reflectance as a
high-throughput method of ozone damage detection in a range of common
broadleaf species.

对流层臭氧会对植被造成广泛损害，但当前针对臭氧诱导植被损伤的监测通常依赖人工叶片检视。植被反射光谱学（Reflectance spectroscopy）可识别不同非生物与生物胁迫因子的独特光谱特征。本研究中，我们测试了高光谱叶片反射率法在臭氧胁迫检测中的应用，受试对象为暴露于5种不同臭氧暴露模式（每日目标最大臭氧浓度范围为30ppb至110ppb）的桤木、山毛榉、桦树、海棠及橡树幼苗。无论是全光谱分析还是简化为代表性组分分析，不同臭氧处理组的高光谱反射率均存在显著差异。臭氧损伤对叶片反射率存在多维度影响，其机制源于色素平衡、含水量与叶片结构组成的改变。基于反射率构建、以可见光绿峰为特征的植被指数可有效区分不同臭氧处理组。对高光谱全波段范围内的迭代归一化差分光谱指数开展目视损伤评分相关性分析，可筛选出用于臭氧损伤检测的关键波长。本研究提出一种新型慢性臭氧损伤指数（Chronic Ozone Damage Index, COzDI），该指数以短波红外区域（shortwave infrared region）的反射峰为特征，与臭氧损伤程度具有高度相关性。本研究结果首次将高光谱反射率法作为高通量检测手段，应用于多种常见阔叶树种的臭氧损伤检测。