RESUMO
Water stress influences plant growth and metabolism. Carnitine, an amino acid involved in lipid metabolism, has been related to responses of plants to abiotic stresses, also modulating their metabolites. Culantro (Eryngium foetidum L.) is a perennial herb, rich in essential oils, native to Latin America, commonly used due to its culinary and medicinal properties. Here, we investigated the effect of exogenous carnitine on morphophysiology and the essential oil profile of culantro plants under water stress. For this, plants were grown under three water conditions: well-watered, drought stress, and re-watered; and sprayed with exogenous carnitine (100 µM) or water (control). Culantro growth was impaired by drought and enhanced by re-watering. Carnitine, in turn, did not reverse drought effects on growth, and impaired the growth of re-watered plants, also improving photosynthetic pigment content. Water conditions and carnitine application changed the essential oil profile of the plants. Drought and re-watering improved the production of eryngial, which was even increased with exogenous carnitine in re-watered plants. In addition, hydroquinone was only produced with the combination of re-watering and carnitine application. The application of exogenous carnitine can be a strategy to induce the production of essential oil compounds with cosmetic and pharmaceutical importance in culantro. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03757-y.
RESUMO
Drought is the major abiotic stress limiting crop production worldwide, with drought events being expected to be harsher and more frequent due to the global warming. In this context, the development of strategies to mitigate the deleterious effects of drought, such as the use of biostimulants, is imperative. Radish is a globally cultivated root vegetable, with high nutritional and phytochemical value. Thus, this study aimed to evaluate the potential of exogenous carnitine application in the mitigation of drought stress on radish morphophysiology. For this, radish plants were grown for 30 days, being irrigated with 80% (well-watered) or 15% (drought stress) of water holding capacity and sprayed with carnitine (5, 50, and 500 µM) or water (0 µM-no carnitine). The experimental design was completely randomized, in a 4 × 2 factorial scheme (carnitine concentrations × water conditions) with six replicates, and each experimental unit consisted of one plant. The gas exchanges, chlorophyll a fluorescence, photosynthetic pigments, electrolyte leakage, relative water content, and biomass production and allocation were evaluated. Drought reduced the photosynthetic capacity of plants by impairing water balance and membrane integrity, decreasing biomass accumulation, mainly in globular roots. The application of low carnitine (5 µM) mitigated these negative effects caused by drought, increasing membrane integrity and water balance of plants, while higher carnitine concentration (50 and 500 µM) aggravated drought stress. This study highlights the potential of carnitine in the mitigation of drought stress on radish plants, supporting its role as a biostimulant. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01308-6.
