Response of Pinus sylvestris L. needles to electromagnetic fields. Cytological and ultrastructural aspects

The effects of pulsed radio frequency electromagnetic field (RF EMF) on plant growth and development are still unclear and contradictory. The aim of this work is to study the impact of RF EMF generated from the Skrunda Radio Location Station, Latvia, on growth and development of pine trees. Pine needles and cones were collected in 1993 from the tops of 50–60-year-old pine trees in four locations near the Skrunda RLS: A — no EMF exposure, B — low EMF exposure, C and D — high EMF exposure. The chloroplasts of mesophyll of second-year needles are ultrastructurally characterised by dense stroma, a compact granal membrane system and variable amounts of starch granules and plastoglobules. Low and especially high EMF exposure from the Skrunda RLS increased the amount of plastoglobules. the structure and export products of Golgi apparatus were changed and in different types of cells, large osmiophilic globules appeared. Evidently, EMF induces modification of Golgi apparatus and switches its functions from synthesis of predecessors of cell walls (lignins) to formation and export of resin predecessors. The stress due to RF EMF generated from Skrunda RLS causes an unspecific response — accelerated resin production and promoted senescence of pine trees.