Bio-stimulants are showing growing success and are gradually replacing synthetic fertilizers in agriculture. Wood distillate (WD), also known as wood vinegar or pyroligneous acid, is a by-product of biomass pyrolysis and is increasingly used as a bio-stimulant for crop production. This study investigated whether weekly foliar applications of 0.25% and 0.50% WD have a differential effect on the chlorophyll and sugar content as well as biomass production in lettuce (Lactuca sativa L.). Moreover, the additional beneficial effect from the addition of corroborants of plant origin such as 3% soy lecithin and 5% flavonoid-rich wood glycolic extract to WD (BF) was investigated. Moreover, the possible toxicological concern from some potentially toxic elements (PTEs), namely Cd, Cu, Fe, Pb, and Zn, which may be abundant in WD was verified. After four weeks, we found that 0.25% WD not only increases lettuce biomass, which has an economic value, but also has beneficial effects on other qualitative parameters such as sugars and total sweetness. On the other hand, the use of 0.5% WD decreased the content of soluble sugars, suggesting a hormetic-type effect. We did not find evidence of further beneficial effects from the addition to WD of plant-derived corroborants, nor of any enrichment in the content of the investigated PTEs.

In the quest for eco‐friendly products with biostimulant properties, foliar application of wood distillate (WD) was tested on the growth and yield of chickpea (Cicer arietinum L.). WD (pyroligneous acid) is a by‐product of plant biomass pyrolysis and is rich in biologically active substances like polyphenols, alcohols, acids and esters. In this work, chickpea plants were sprayed weekly with 100 ml 0.25% (v/v) chestnut (Castanea sativa Mill.) WD during the whole growing period, and at the end physiological and nutritional analyses were performed both on the whole plant and on seeds. While plant height and weight did not change significantly, seeds showed an increase in diameter (+11.2%) and weight (+33.3%), and in the content of starch (+45.9%), total soluble protein (+12.9%), total polyphenol (+16.4%) and antioxidant power (+28.4%). Overall, the content of essential free amino acids increased, except for lysine (−3.4%), phenylalanine (−10.5%) and methionine (−13.7%). Among all the mineral elements analysed, only potassium and magnesium decreased in WD‐treated plants, although values were within the common range for chickpea seeds. These results are a clear demonstration of the effectiveness of the use of WD on increasing the nutritional qualities of the edible parts of crop species, thus representing a possible solution to counteract human malnutrition and famine as well as environmental concerns.

This study investigated the suitability of X-ray fluorescence (XRF) analysis for routine multi-elemental composition analysis, checking its analytical capabilities by measuring a wide array of certified reference materials of soil and plant origin. A portable XRF analyzer was used to evaluate 32 soil and 12 plant standard materials, using both the Soil and Geochem mode, with sequential beams, allowing the detection of a wide range of elements. Recovery rates were calculated by comparing XRF measurements with certified values, and their correlations were verified through the Spearman coefficient. The results demonstrated the reliability of XRF measurements for soil samples, with a large number of elements showing a good or very good recovery and strong correlations with certified values. For plant samples, XRF largely overestimated the certified values, but the strong statistically significant correlations for almost all tested elements allowed us to correct this systematic bias, using the reported median value for dividing the value obtained via XRF. The Geochem mode emerged as more reliable for a larger number of elements. It was concluded that XRF may be a suitable alternative to ICP-MS in routine multi-elemental composition analysis.

This study evaluated the physiological and biochemical responses of chickpea (Cicer arietinum L.) to foliar application of cineole, carvacrol, and thymol at concentrations of 500 and 1000 ppm. Carvacrol at 1000 ppm significantly enhanced fresh biomass (+15.4%) and aerial biomass (+46.2%), whereas thymol significantly reduced plant height (−20.2%) and overall biomass, yet notably increased chlorophyll content (+23.3%) and vitamin C levels (+41.4%) at the same concentration. Cineole significantly improved antioxidant capacity by increasing total phenolic content (+15.5% at 1000 ppm) and total flavonoid content (+19.1% at 500 ppm), but simultaneously decreased soluble protein synthesis and chlorophyll content (−39% at 500 ppm). Mineral analysis showed notable increases in calcium content following treatment with cineole (+30.5% at 1000 ppm) and carvacrol (+32% at 500 ppm), while thymol at 1000 ppm significantly reduced phosphorus, potassium, manganese, iron, copper, and zinc accumulation. Molecular docking and dynamic simulations revealed strong interactions of thymol and carvacrol with essential enzymes, specifically ascorbate peroxidase and phenylalanine ammonia-lyase, which are involved in antioxidant and phenolic metabolism pathways. These molecular interactions suggest potential contributions of thymol and carvacrol to plant stress resilience mechanisms, although further experimental validation is needed to confirm their roles in vivo. These findings emphasize the importance of optimizing monoterpene concentrations, indicating that carefully calibrated treatments could effectively enhance chickpea growth, nutritional quality, and stress tolerance within sustainable agricultural practices.

As a consequence of the Russian invasion of Ukraine, Europe is facing a shortage of chemical fertilizers for agriculture. Therefore, the use of byproducts of biomass anaerobic digestion, e.g., solid (SD) and liquid (LD) digestate, could be a key solution to cope with this problem. In this framework, the present study aimed to evaluate the effect of both SD and LD, derived from the same feedstock, on the biometric, physiological, and biochemical parameters of lettuce (Lactuca sativa L.) plants. Compared to the controls, the plants treated with 3% (w/w) SD showed a reduction in leaf fresh biomass, chlorophyll content, performance index, fractal dimension, and antiradical activity, while vitamin C increased by 18.8%. An opposite response was observed for the lettuce plants treated with 3% (v/w) LD, which showed an increase in all the above-mentioned parameters, except for vitamin C, which decreased by 39.8%. Interestingly, the content of malondialdehyde, which is correlated with cell membrane lipid peroxidation, increased in the SD-treated plants (+39.7%) and decreased (−42.1%) in the LD-treated plants. These results strongly support the use of LD in agriculture as a valuable product to improve the productivity and nutritional quality of crop plants.