Seed Treatment with Electromagnetic Field Induces Different Effects on Emergence, Growth and Profiles of Biochemical Compounds in Seven Half-Sib Families of Silver Birch

Abstract

In the context of climate change, strategies aimed at enhancing trees’ resistance to biotic and abiotic stress are particularly relevant. We applied an electromagnetic field (EMF) seed treatment to observe changes in the establishment and content of biochemical compounds in silver birch seedlings induced by a short (1 min) seed exposure to a physical stressor. The impact of EMF treatment was evaluated on seedling emergence and growth of one-year-old and two-year-old seedlings from seven half-sib families of silver birch. The effects on numerous biochemical parameters in seedling leaves, such as total phenolic content (TPC), total flavonoid content (TFC), amounts of photosynthetic pigments, total soluble sugars (TSS), level of lipid peroxidation level, antioxidant activity and activity of antioxidant enzymes, were compared using spectrophotometric methods. The results indicated that, in one-year-old seedlings, two of seven (60th and 73rd) half-sib families exhibited a positive response to seed treatment with EMFs in nearly all analyzed parameters. For example, in the 60th family, seed treatment with EMFs increased the percentage of emergence by 3 times, one-year-old seedling height by 71%, leaf TPC by 47%, antioxidant activity by 2 times and amount of chlorophyll a by 4.6 times. Meanwhile, the other two (86th and 179th) families exhibited a more obvious positive response to EMF in two-year-old seedlings as compared to one-year-old seedling controls. The results revealed that short-term EMF treatment of silver birch seeds can potentially be used to improve seedling emergence and growth and increase the content of secondary metabolites, antioxidant capacity and photosynthetic pigments. Understanding of the impact of EMFs as well as the influence of genetic differences on tree responses can be significant for practical applications in forestry. Genetic selection of plant genotypes that exhibit positive response trends can open the way to improve the quality of forest stands.

Changes in Biologically Active Compounds in Pinus sylvestris Needles after Lymantria monacha Outbreaks and Treatment with Foray 76B

“…Higher concentrations of the TFC in undamaged/healthy P. sylvestris forests indicate their importance in tree resistance against defoliating insects [ 50 ]. Even low concentrations of numerous flavonoids increase plant immune system [ 51 ] and might be a potential indicator of a higher forest stability and resistance to defoliators [ 50 , 52 ]. The results from our study showed that although treatment with Foray 76B had a temporary increment effect on the TFC, the changes did not remain in the following year after the outbreaks, leading to potential repeated damage by insect pests and pathogens in the future.…”

“…According to other studies, biotic disruptions, exemplified by the appearance of insect herbivore outbreaks or pathogen infestations, induce physiological stress in plants and can increase the production of photosynthetic pigments [ 51 , 53 , 54 ]. Photosynthesis-related pigments are characterized by their ability to protect the photosystems from photo radiation related to oxidative stress [ 55 ].…”

“…TPC was determined by using Folin–Ciocalteu reagent, according to Čėsnienė et al (2023) [ 51 ] methodology. Analysis was performed in 96-well microplates; the reaction mixture consisted of Folin–Ciocalteu reagent (1:10) (VWR International GmbH, Vienna, Austria) and Na 2 CO 3 (10%) (Firma Chempur, Piekary Śląskie, Poland).…”

“…TFC was detected based on the formation of a flavonoid–Al(III) complex [ 51 ]. Analysis of TFC was performed in 96-well micro plates; and the reaction mixture consisted of absolute EtOH (Merck KGaA, Darmstadt, Germany), AlCl 3 (10%, w / v ) (99% purity) (Alfa Aesar GmbH & Co KG, Karlsruhe, Germany), of C 2 H 3 KO 2 (1M, 99% purity) (Sigma-Aldrich, Darmstadt, Germany) and dH 2 O.…”