Species discrimination of plant roots by Fourier transform infrared (FTIR) spectroscopy

了解植物物种之间的地下竞争是理解间作农业系统、作物与杂草之间以及自然生态系统中复杂相互作用的核心部分。到目前为止，还没有一种简便、快速的土壤根系种类鉴别方法。我们将开发一种基于傅里叶变换红外(FTIR)-衰减全反射（ATR）光谱的多种植物根系鉴别方法，并扩大其应用范围。FTIR-ATR光谱的吸光度模式就像一个单独的指纹一样代表了化学样品的成分。采用多变量方法，根据光谱相似性和化学相似性对光谱进行分组，实现物种识别。我们将研究豌豆和燕麦的根，以及玉米和谷仓的根，使用不同的品种/产地在温室中生长。豌豆和燕麦是推荐的间作品种，以环境可持续的方式获得更高的粮食和蛋白质产量。为了评估间作对田间根系分布的影响，将使用移动FTIR光谱仪直接在土壤剖面壁上测量根段。通过提取主要根化合物（脂类、蛋白质、碳水化合物）并记录其FTIR-ATR光谱作为参考，我们将阐明物种特异性差异的化学基础。

Comprehension of belowground competition between plant species is a central part in understanding the complex interactions in intercropped agricultural systems, between crops and weeds as well as in natural ecosystems. So far, no simple and rapid method for species discrimination of roots in the soil exists. We will be developing a method for root discrimination of various species based on Fourier Transform Infrared (FTIR)-Attenuated Total Reflexion (ATR) Spectroscopy and expanding its application to the field. The absorbance patterns of FTIR-ATR spectra represent the chemical sample composition like an individual fingerprint. By means of multivariate methods, spectra will be grouped according to spectral and chemical similarity in order to achieve species discrimination. We will investigate pea and oat roots as well as maize and barnyard grass roots using various cultivars/proveniences grown in the greenhouse. Pea and oat are recommendable species for intercropping to achieve superior grain and protein yields in an environmentally sustainable manner. To evaluate the effects of intercropping on root distribution in the field, root segments will be measured directly at the soil profile wall using a mobile FTIR spectrometer. By extracting the main root compounds (lipids, proteins, carbohydrates) and recording their FTIR-ATR spectra as references, we will elucidate the chemical basis of species-specific differences.