Drought, exacerbated by climate change, represents a growing challenge for agriculture, significantly impacting on crops such as chili peppers (Capsicum), essential in the global diet. This work evaluated the response to water stress by suspending irrigation in Siete Caldos chili pepper plants (Capsicum frutescens). Control plants were watered every 48 h, while stress was induced in the test plants by withholding irrigation for 14 days, followed by an evaluation of recovery through rehydration on day 15. Growth parameters such as the fresh weight of the aerial part, root length, and number of flower buds showed significant differences between the two groups from the eighth day onwards. However, physiologically and biochemically stress-induced decreased relative water content, membrane stability, and chlorophyll content, coupled with increased electrolyte leakage, proline content, and antioxidant activity (catalases and peroxidases), were observed starting on the third day. These effects were more severe on day 14. At the molecular level, the expression of stress response genes (AP2, LOX2, CAT, CuSOD, MnSOD, and P5CS) was quantified at days 3, 14, and 15, revealing differences in transcript levels between the treatments. Finally, rehydration in the stressed plants resulted in the recovery of the evaluated parameters and a survival rate of 100%. Therefore, chili pepper has tolerance mechanisms that allow it to withstand a period of 14 days without irrigation, without reaching its permanent wilting point, and it can recover if conditions improve. This study underscores the complexity of plant responses and tolerance mechanisms to drought, providing insights into the behavior of semi-domesticated species.

Currently, residual frying oil has three purposes: it is used again in the preparation of fried foods, mixed with new vegetable oil, which can cause cardiovascular disease in the consumer; it is collected by government institutions, without having an exclusive use; or it is thrown into the drain, causing serious pollution problems to water resources. An alternative is to transform it into biodiesel, through transesterification with methanol, to be used in internal combustion engines, biodiesel-diesel mixtures of 10:90, 15:85 and 20:80 (v/v), according to international regulations in such a way that, in the combustion process, less CO₂ and greenhouse gas emissions are generated. Residual frying oil served as raw material, which was collected, mixed and homogenized to evaluate physicochemical properties before transformation. The biodiesel generated had a density of 0.886 g L⁻¹, an acidity of 0.516%, a viscosity of 7.535 mm² s⁻¹, a flash point of 166.8 °C and an oxidative stability of 49 days at 25 °C. Additionally, the content of functional groups characteristic of biodiesel formation was evaluated by Infrared Spectroscopy. The Biodiesel obtained is of good quality for use in internal combustion engines and agricultural machinery, thus validating its continuous production and complying with the standard values of international regulations.

In the current search for products that are friendly to the environment, the intent is to reduce the use of domestic, food and industrial waste of mineral origin, thereby creating new products that are functional in industrial and agricultural processes. That is why the use of raw chicken skin fat was evaluated for the creation of a biolubricant with possible applications in the operation of heavy machinery, such as agricultural tractors. The acute toxicity of the biolubricant made from transesterified fatty acids obtained from chicken skin fat was determined experimentally, using bioassays with Eisenia fetida as a test organism, by means of the median lethal concentration (LC50) using the probit method (p < 0.05) on the filter paper at 48 h and on an artificial substrate at 14 days, resulting in an LC50 of 878.675 mg mL⁻¹ or 0.0268 mg cm⁻² and 35.2348 mg kg⁻¹, respectively. Likewise, the physiological damage was determined by means of histology, and it could be observed that there was no damage on the Eisenia fetida cell tissue. This indicates that the biolubricant is suitable for use in agricultural machinery since, in the event of an accidental spill, it does not cause damage to the soil or the organisms that live in it, as well as to the people who handle this type of product in their daily work.

Sustainable agricultural practices increasingly focus on natural bioactive agents for managing phytopathogens. This study investigates the antifungal and phytotoxic properties of methanolic bioextracts derived from Plantago major leaves (MBPm) and Sambucus nigra roots (MBSn) to explore their potential applications. Bioextracts were prepared through methanolic maceration, with yields of 6.02% (P. major) and 6.42% (S. nigra). Antifungal assays evaluated inhibitory effects on Fusarium oxysporum, Corynespora cassiicola, and Penicillium oxalicum, while phytotoxicity assays assessed concentration-dependent impacts on Solanum lycopersicum seed germination. A qualitative evaluation of major polyphenolic compounds was conducted using Ultra-Performance Liquid Chromatography coupled with a Photodiode Array Detector and Electrospray Ionization Mass Spectrometry (UPLC-PDA-ESI-MS) to identify bioactive compounds known for their significant biological activity. P. major bioextracts demonstrated significant inhibition of F. oxysporum (90.06%) and C. cassiicola (83.19%), while S. nigra bioextracts achieved 89.65% and 92.16% inhibition, respectively. Both bioextracts showed minimal impact on P. oxalicum, with effects observed only at 50 mg/mL. Low concentrations of S. nigra bioextract enhanced seed germination, whereas higher doses inhibited it. Identified bioactive compounds included acteoside, isoacteoside, chlorogenic acid, and dicaffeoylquinic acid isomers. The findings highlight the potential of these bioextracts as biocontrol agents and modulators of seed germination processes, contributing to sustainable agricultural strategies. While this study was conducted under controlled laboratory conditions, these results provide a strong foundation for future evaluations in field settings to explore their broader agricultural applications.

Fungal pathogens represent a major constraint for agricultural productivity, and plant secondary metabolites play an important role in natural defence mechanisms. The present study investigated organ-specific antifungal activity and qualitative phytochemical profiles of methanolic extracts obtained from roots, leaves, and fruits of Parmentiera aculeata against the phytopathogenic fungus Penicillium oxalicum. Plant materials were dried, macerated in methanol, and subjected to qualitative phytochemical screening. Antifungal activity was evaluated through spore germination inhibition assays at different extract concentrations, and data were analysed using one-way analysis of variance followed by Tukey’s test (p < 0.05). Qualitative analyses revealed the presence of flavonoids, saponins, tannins, and phenolic compounds in all organs, with variation among tissues. Significant differences in antifungal activity were observed among plant organs and concentrations. Root extracts exhibited the highest inhibition of spore germination (76.95 % at 50 mg mL-¹), followed by fruit extracts (61.55 %) and leaf extracts (23 %). Statistical analysis confirmed a significant effect of extract type and concentration on fungal inhibition (F = 6.008, p < 0.05). These results indicated differential allocation of bioactive secondary metabolites among plant organs and are consistent with organ-specific chemical defence patterns in P. aculeata.