Diagnostics of the Response of Plants of the Genus Pinus L. to Abiotic Stress by Raman Spectroscopy

Pine plants of urban and suburban plantings in Moscow and Beijing are assessed in order to diagnose the adaptation of three pine species (Pinus sylvestris L., P. mugo Turra, and P. tabuliformis Carr.) to abiotic stress occurring in urban environments. The noninvasive biochemical measurements of pine needles using Raman spectrometry (Raman microscopy–spectroscopy) has allowed us to register changes in their biochemical composition that are not yet manifested externally. The accumulation of carotenoids, anthocyanins, and polyamine spermine is observed in the needles of P. sylvestris under prolonged abiotic stress (anthropogenic air pollution). The response of pine plants to in vivo stress is further confirmed by common destructive chemical extraction methods. The accumulation of macro- and microelements is observed in the needles of P. sylvestris growing on the territory with maximum anthropogenic load when compared with background values: maximum levels of Fe, Cu, Mn, Cr, Cr, Ni, Ag, Pb, Ba, and Cd exceeding background values by 2.7–23.5 times. The analysis of Raman spectra allows us to recommend microscopy–spectroscopy for the high-throughput stress phenotyping of urban pine plantations. The ranking of the species by resistance to urban conditions resulted in the following series Pinus tabuliformis → Pinus sylvestris ≈ Pinus mugo.