Effect of Pyroligneous Acid on the Productivity and Nutritional Quality of Greenhouse Tomato

Foliar application of pyroligneous acid acts synergistically with fertilizer to improve the productivity and phytochemical properties of greenhouse-grown tomato

Pyroligneous acid (PA) is rich in bioactive compounds and known to have the potential to improve crop productivity and phytochemical content. However, the synergistic effect of PA and fertilizer has not been thoroughly studied. In this study, we assessed the biostimulatory effect of different rates of foliar PA application (i.e., 0, 0.25, 0.5, 1, and 2% PA/ddH2O (v/v)) combined with full rate (i.e., 0.63, 0.28, 1.03 g) and half rate of nitrogen-phosphorus-potassium (NPK) fertilizer on the yield and nutritional quality of greenhouse-grown tomato (Solanum lycopersicum 'Scotia'). Plants treated with 0.25% and 0.5% PA showed a significantly (p < 0.001) higher maximum quantum efficiency of photosystem II (Fv/Fm) and increased potential photosynthetic capacity (Fv/Fo), especially when combined with the full NPK rate. Leaf chlorophyll was significantly (p < 0.001) increased by approximately 0.60 and 0.49 folds in plants treated with 2% PA and full NPK rate compared to no spray and water, respectively. Total number of fruits was significantly (p < 0.001) increased by approximately 0.56 folds with the 2% PA irrespective of the NPK rate. The combined 2% PA and full NPK rate enhanced total fruit weight and the number of marketable fruits. Similarly, fruit protein, sugar and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity were significantly (p < 0.001) enhanced by the combined 2% PA and full NPK rate. In contrast, the 0.5% PA combined with half NPK rate increased fruit carotenoid and phenolic contents while the 2% PA plus half NPK rate enhanced fruit flavonoid content. Generally, the synergistic effect of PA and NPK fertilizer increased fruit elemental composition. These showed that foliar application of 2% PA with full NPK rate is the best treatment combination that can be adopted as a novel strategy to increase the productivity and quality of tomato fruits. However, further study is required to investigate the molecular basis of PA biostimulatory effect on plants.

Nutritionally enriched tomatoes (Solanum lycopersicum L.) grown with wood distillate: chemical and biological characterization for quality assessment

Bio-based products are nowadays useful tools able to affect the productivity and quality of conventionally cultivated crops. Several bio-based products are currently on the market; one of the newest and most promising is the wood distillate (WD) derived from the pyrolysis process of waste biomass after timber. Its foliar application has been widely investigated and shown to promote the antioxidant profile of cultivated crops. WD was used here as additive for the cultivation of tomato (Solanum lycopersicum L.) plants. The application improved quality (chemical) parameters, minerals, polyphenols, and lycopene contents of tomato fruits. The extracts of WD-treated and untreated tomatoes have been chemically and biologically characterized. The 1 H-NMR and ESI-mass spectrometry analyses of the extracts revealed the presence of different fatty acids, amino acids and sugars. In particular, the WD-treated tomatoes showed the presence of pyroglutamic acid and phloridzin derivatives, but also dihydrokaempferol, naringenin glucoside, cinnamic acid, and kaempferol-3-O-glucoside. When tested in cells, the extracts showed a promising anti-inflammatory profile in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Furthermore, the extracts displayed a slight vasorelaxant activity on rat aorta rings (either endothelium-denuded or endothelium-intact) pre-contracted with phenylephrine or potassium chloride. PRACTICAL APPLICATION: Wood distillate has been used for tomato plant growth. Tomatoes showed improved nutritional parameters, and their extracts displayed antioxidant and anti-inflammatory activities.

Exploring sustainable alternatives: Wood distillate alleviates the impact of bioplastic in basil plants

The growing interest in bioplastics and bio-based crop management products in agriculture is driven by the Sustainable Development Goals of the 2030 Agenda. However, recent research has raised concerns about the sustainability of bioplastics due to their potential negative impact on crop growth and yield, with implications for the environment and human health. In this study, wood distillate (WD) was evaluated as a natural enhancer of plant growth and defence system to mitigate the negative impact of a starch-based bioplastic on basil (Ocimum basilicum L.) plants. The study analyzed physiological and biochemical changes in basil plants subjected for 35 days to single or combined treatments of WD and bioplastic by measuring biomarkers of healthy growth, such as soluble proteins, sugars, vitamin C, and malondialdehyde (MDA). The results showed that WD promoted basil development, whereas the presence of bioplastic hindered it. Interestingly, WD did not affect sugars but increased vitamin C by 12 %, which is considered a positive effect as changes in sugar levels could indicate plant stress. In contrast, bioplastic resulted in reduced sugars (-41 %) and increased (+17 %) MDA level, while vitamin C content remained unchanged. However, when WD was added to plants grown with bioplastic, it elevated the levels of all examined parameters, except for sugars and vitamin C, which experienced reductions (-66 % and 33 %, respectively). Intriguingly, despite this reduction, the observed direct correlation between sugar and vitamin C contents was maintained, indicating that the decrease in sugar content may have reached a critical threshold. This study suggests that the use of WD has the potential to alleviate the adverse effects of bioplastic on basil growth and development and highlights the importance of adopting sustainable practices in agriculture, as well as the need for a critical assessment of the environmental impact of new technologies and products.