<abstract xmlns="http://www.w3.org/1999/xhtml">

Salinity is one of the most important abiotic stresses that significantly decreases the productivity of agricultural crops. Melatonin (MT) acts as an antioxidant and plays a vital role in overcoming oxidative damage. However, previous literature has not provided a clear understanding of the impact of MT on lettuce plants under salinity stress. So, we investigated the effect of exogenous MT at 0 μM, 50 μM, 100 μM and 150 μM on lettuce plants grown under salinity stress (0 mM NaCl, 50 mM NaCl and 100 mM NaCl) with respect to vegetative growth, photosynthetic pigments, relative water content (RWC), electrolyte leakage (EL), malondialdehyde (MDA), H2O2, O2•- and antioxidants enzymes. Results showed that NaCl stress significantly decreased vegetative growth, RWC and photosynthetic pigments and in contrast enhanced dry matter, EL, MDA, H2O2, O2•-, Na+, Cl-, peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) of lettuce plants compared to non-salinized control. The results demonstrated that under salinity conditions, foliar applications of MT significantly alleviated the harmful effects of salinity and increased number of leaves, leaf area, fresh weight, chlorophyll (a), chlorophyll (b), total chlorophyll, carotenoids and RWC in comparison to untreated plants (control). Meanwhile, dry matter, MDA, H2O2, O2•-, Na+, Cl-, POD, SOD and GR were significantly decreased compared to untreated lettuce plants. In this respect, spraying MT at 150 μM ranked the first, then 100 μM, compared to the lower concentration (50 μM). In conclusion, MT application can be used to alleviate harmful effects of salinity stress.
</abstract>

Salinity is one of the most important abiotic stresses that significantly decreases the productivity of agricultural crops. Melatonin (MT) acts as an antioxidant and plays a vital role in overcoming oxidative damage. However, previous literature has not provided a clear understanding of the impact of MT on lettuce plants under salinity stress. So, we investigated the effect of exogenous MT at 0 μM, 50 μM, 100 μM and 150 μM on lettuce plants grown under salinity stress (0 mM NaCl, 50 mM NaCl and 100 mM NaCl) with respect to vegetative growth, photosynthetic pigments, relative water content (RWC), electrolyte leakage (EL), malondialdehyde (MDA), H2O2, O2•- and antioxidants enzymes. Results showed that NaCl stress significantly decreased vegetative growth, RWC and photosynthetic pigments and in contrast enhanced dry matter, EL, MDA, H2O2, O2•-, Na+, Cl-, peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) of lettuce plants compared to non-salinized control. The results demonstrated that under salinity conditions, foliar applications of MT significantly alleviated the harmful effects of salinity and increased number of leaves, leaf area, fresh weight, chlorophyll (a), chlorophyll (b), total chlorophyll, carotenoids and RWC in comparison to untreated plants (control). Meanwhile, dry matter, MDA, H2O2, O2•-, Na+, Cl-, POD, SOD and GR were significantly decreased compared to untreated lettuce plants. In this respect, spraying MT at 150 μM ranked the first, then 100 μM, compared to the lower concentration (50 μM). In conclusion, MT application can be used to alleviate harmful effects of salinity stress.

Effects of melatonin on lettuce plant growth, antioxidant enzymes and photosynthetic pigments under salinity stress conditions

Folia Horticulturae

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Salinity is one of the most important abiotic stresses that significantly decreases the productivity of agricultural crops. Melatonin (MT) acts as an...

Effects of melatonin on lettuce plant growth, antioxidant enzymes and photosynthetic pigments under salinity stress conditions

Article Category: ORIGINAL ARTICLE

Published Online: Feb 05, 2024

Page range: 1 - 17

Received: Sep 30, 2023

Accepted: Dec 22, 2023

DOI: https://doi.org/10.2478/fhort-2024-0001

Keywords
abiotic stress, free radicals, exogenous MT, L., foliar application, productivity, vegetative growth

© 2024 Hemat A. EL-Bauome et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Effects of melatonin on lettuce plant growth, antioxidant enzymes and photosynthetic pigments under salinity stress conditions

Article Category: ORIGINAL ARTICLE

Published Online: Feb 05, 2024

Page range: 1 - 17

Received: Sep 30, 2023

Accepted: Dec 22, 2023

DOI: https://doi.org/10.2478/fhort-2024-0001

Keywordsabiotic stress, free radicals, exogenous MT, L., foliar application, productivity, vegetative growth

© 2024 Hemat A. EL-Bauome et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
abiotic stress, free radicals, exogenous MT, L., foliar application, productivity, vegetative growth