The influence of environmental condition on the creation of organic compounds in Pinus sylvestris L. rhizosphere, roots and needles

Abstract

Abstract Key message Studied organic molecules in Pinus sylvestris L. seem to have acted as a safety net for metal transport, chelation and sequestration, allowing adaptation and growth under highly polluted conditions. Abstract Pinus sylvestris L. is known for its ability to survive in areas of highly elevated metal pollution, such as flotation tailings. The aim of the study was to estimate the content of selected organic molecules (including aliphatic low molecular weight organic acids (ALMWOAs), phenolic compounds and terpenes) and the physiological mechanisms underlying differences in metal/metalloid tolerance of P. sylvestris growing in unpolluted (soil) and polluted (flotation tailings) areas. The dominant ALMWOAs in rhizosphere soil extracts were citric acid followed by malic and oxalic acids, whereas in flotation tailings malic and oxalic acids. In roots and needles, the content of ALMOWAs was significantly higher in P. sylvestris L. tissue from flotation tailings in comparison to soil. Phenolic compounds were detected only in roots and needles, with a generally higher content of nearly all detected compounds from flotation tailings. The composition of roots did not contain all the compounds detected in needles. The profile of needles additionally contained four hydroxybenzoic, protocatechuic and salicylic acids. In pine needles, 24 volatile terpenes were identified in total. The content of these compounds in pine needles from the polluted area was markedly different from the unpolluted area. The dominant volatile monoterpenes in P. sylvestris L. needles from the unpolluted area was three carene, while in pine needles from the polluted area monoterpenes α-pinene was dominant.