Cadmium (Cd) stress is considered one of the most harmful abiotic stresses due to its toxicity and ability to alter the ultrastructure of plants. Lettuce (Lactuca sativa L.) can readily accumulate Cd from the soil, but elevated levels negatively affect its development and nutritional quality. In this study, the efficacy of a synergistic application of chitosan and spermidine was evaluated to improve Cd metal tolerance or its exclusion in lettuce. A pot experiment was conducted in a four-way completely randomized design (CRD) with three replicates, using two L. sativa varieties (VRIL-0205 and Green Check). The treatments included Cd stress (10 ppm CdCl2), chitosan (200 ppm), and spermidine (145 ppm), along with their respective controls.
The negative effects of Cd stress on the morphological, physiological, and biochemical attributes of both L. sativa varieties were evaluated, along with the counter effects of chitosan and spermidine alone and in combination. Cd stress resulted in significant accumulation of Cd2+ ions in the shoots of both varieties (0.038 mg kg−1 in VRIL-0205 and 0.041 mg kg−1 in Green Check). It also impaired growth, biomass, gas exchange, water relations, antioxidant activities, and nutrient uptake in both varieties.
Foliar application of both chitosan and spermidine improved growth, biomass, chlorophyll content, photosynthesis rate, stomatal conductance, water content, antioxidant activities, and nutrient uptake in both control and stressed plants. Their combined treatment reduced stress indicators, including relative membrane permeability (VRIL-0205; 19% and Green Check; 22%), H2O2 (VRIL-0205; 27% and Green Check; 26%), and malondialdehyde content (VRIL-0205; 6% and Green Check; 7%) in stressed plants, compared to stress-only plants.
These findings show that the synergistic application of chitosan and spermidine effectively mitigates Cd toxicity in both L. sativa varieties and improves their growth under stress conditions. This study provides insight into the potential use of chitosan and spermidine foliar spray as sustainable tools for improving Cd resilience in crop plants.
Rafique, M., Noreen, Z., Usman, S., Shah, A. A., Taj, H., A., M., & Lee, I. J. (2025). Mitigation of adverse effect of cadmium toxicity in lettuce (Lactuca sativa L.) through foliar application of chitosan and spermidine. Scientific Reports, 15(1), 1-21. https://doi.org/10.1038/s41598-025-93672-4
Source: Nature Magazine