Pull–push molecules containing dimethylaniline and aromatic hydrocarbon linked by an acetylene unit were studied using spectroscopic methods and DFT theoretical calculations. Spectral and photophysical properties of N,N-dimethyl-4-(naphthalen-1-ylethynyl)aniline, N,N-dimethyl-4-(naphthalen-2-ylethynyl)aniline, 4-(athracen-9-ylethynyl)-N,N-dimethylaniline were studied in 26 solvents (non-polar, polar aprotic and protic). The influence of solvent properties on the spectral and photophysical properties of the compounds studied was analyzed using empirical Riechardt's solvent polarity index as well as Catalán and Kamlet–Tatf multi-parameter solvent scales. The change of the dipole moment in the excited state was estimated based on Bilot–Kawski theory. Using the solvatochromic method, the change of hydrogen bond energy in the excited state was calculated. Theoretical calculations confirm the conclusions arising from experimental studies.

Tolerance to heavy metals in plants is a model process used to study adaptations to extremely unfavorable environments. One species capable of colonizing areas with high contents of heavy metals is Armeria maritima (Mill.) Wild. A. maritima plants growing in metalliferous areas differ in their morphological features and tolerance levels to heavy metals compared to individuals of the same species growing in non-metalliferous areas. The A. maritima adaptations to heavy metals occur at the organismal, tissue, and cellular levels (e.g., the retention of metals in roots, enrichment of the oldest leaves with metals, accumulation of metals in trichomes, and excretion of metals by salt glands of leaf epidermis). This species also undergoes physiological and biochemical adaptations (e.g., the accumulation of metals in vacuoles of the root’s tannic cells and secretion of such compounds as glutathione, organic acids, or HSP17). This work reviews the current knowledge on A. maritima adaptations to heavy metals occurring in zinc–lead waste heaps and the species’ genetic variation from exposure to such habitats. A. maritima is an excellent example of microevolution processes in plants inhabiting anthropogenically changed areas.

Due to the contamination of soil with lead, there is still a danger of lead penetrating into our diet through crops. So far, no method has been developed to reduce the concentration of this toxic element in plants and to prevent it from entering the biological cycle. In this paper, an attempt was made for the first time to reduce lead concentrations in plants by using foliar calcium preparations. This was based on the hypothesis that an increased amount of calcium in the plant would lead to the reduction in the amount of lead as the entry routes of calcium and lead are similar; therefore, an increase in the amount of calcium will result in the saturation of the routes through which lead enters cells (e.g. calcium channels). It should be clarified that the research was experimental. Three crop species ( Linum usitatissimum L., Solanum lycopersicum L., Cucumis sativus L.) were tested at the organismal level, whereas the epidermis of Allium cepa L. was used to conduct tests at the cellular level. The InCa calcium transport activator (by Plant Impact) was selected for the test, followed by calcium nitrate. The preparations were administered foliarly. Lead, on the other hand, was applied to roots before adding lead nitrate into the mineral medium. The plants were cultivated hydroponically. The growth and development of seedlings, the concentration of lead in roots and shoots and the microscopic visualisation of lead in plant organisms and cells were studied. Ultimately, the InCa activator administered foliarly was shown to reduce the concentration of lead in plant organs by approximately 44%. Further findings revealed that the mechanism of this process mainly resulted from the supply of calcium nitrate to plant leaves. A commercial calcium foliar fertiliser also showed a similar effect. The potential to reduce the uptake of lead by crops by approximately 44% is a very satisfactory result. In addition, spraying plants with InCA biostimulant and calcium nitrate is environmentally friendly. This is cutting-edge research that was described for the first time in the present paper.