Consideration of hyperspectral data in intraspecific variation (spectrotaxonomy) in Prosopis juliflora (Sw.) DC, Saudi Arabia

Abstract

Classification is the science that arranges organisms in groups according to their similarities and differences. In plant science, there are many aspects of classifications. For instance, there is morphological, anatomical, palynological, molecular, and chemical classification. All these types consume time, effort, and money. In this research, new technology is tested to identify the differences between plants. Spectroradiometer will help in classifying Prosopis juliflora (Sw.) DC in Bahrah region in Saudi Arabia. Spectroradiometer technology is applied to a sample of 40 taxa of P. juliflora in two different seasons. Within each sample site, measurements were taken at a high sun angle from 10:00 am to 2:00 pm. Results showed that spectroradiometer indicated the existence of significant differences among P. juliflora taxa. Correspondingly, the spectroradiometer engenders the spectral responses of the targeted species in the region between 400 and 2,500 nm wavelength. The spectral behavior of P. juliflora in four seasons was demonstrated as season dependent. The variance-based principal component analysis divided the investigated samples into two groups, either positively correlated or negatively correlated according to the seasonal data collection. Sample number 5 in the quantile’s slicing analysis maintained a stable behavior when it was exposed to 100% wavelength. P. juliflora behavior was stabilized in the infrared (IR) samples (4,5), the shortwave IR (SWIR) (3,4,5), and thermal IT (TIR) (3,4,5,6) at the quantile range of >75. While in the quantile range <25, we found the stability behavior in the IR samples (2,8,10), the SWIR (2,7,8,10), and in TIR (2,7,8,10). Therefore, this approved that the spectroradiometer is useful as the first classification process. More studies are needed to support this finding, such as chemical and molecular investigations.

Keywords

• arid environments
• overlapped taxa
• phenology
• prosopis juliflora
• spectral classification
• spectroradiometer