Enhancement of Salinity Stress Tolerance in Lettuce (<i>Lactuca sativa</i> L.) via Foliar Application of Nitric Oxide
Hasan Sardar,
Zubair Khalid,
Muhammad Ahsan,
Safina Naz,
Aamir Nawaz,
Riaz Ahmad,
Kashif Razzaq,
Saikh M. Wabaidur,
Cédric Jacquard,
Ivan Širić,
Pankaj Kumar,
Sami Abou Fayssal
Affiliations
Hasan Sardar
Department of Horticulture, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan
Zubair Khalid
Department of Horticulture, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan
Muhammad Ahsan
Department of Horticultural Sciences, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan
Safina Naz
Department of Horticulture, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan
Aamir Nawaz
Department of Horticulture, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan
Riaz Ahmad
Department of Horticulture, The University of Agriculture, Dera Ismail Khan 29111, Pakistan
Kashif Razzaq
Department of Horticulture, Muhammad Nawaz Shareef University of Agriculture, Multan 60000, Pakistan
Saikh M. Wabaidur
Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
Cédric Jacquard
Research Unit Induced Resistance and Plant Bioprotection, University of Reims, EA 4707 USC INRAe 1488, SFR Condorcet FR CNRS 3417, 51100 Reims, France
Ivan Širić
University of Zagreb, Faculty of Agriculture, Svetosimunska 25, 10000 Zagreb, Croatia
Pankaj Kumar
Agro-Ecology and Pollution Research Laboratory, Department of Zoology and Environmental Science, Gurukula Kangri (Deemed to Be University), Haridwar 249404, India
Sami Abou Fayssal
Department of Agronomy, Faculty of Agronomy, University of Forestry, 10 Kliment Ohridski Blvd, 1797 Sofia, Bulgaria
Salt stress negatively affects the growth, development, and yield of horticultural crops. Nitric oxide (NO) is considered a signaling molecule that plays a key role in the plant defense system under salt stress. This study investigated the impact of exogenous application of 0.2 mM of sodium nitroprusside (SNP, an NO donor) on the salt tolerance and physiological and morphological characteristics of lettuce (Lactuca sativa L.) under salt stress (25, 50, 75, and 100 mM). Salt stress caused a marked decrease in growth, yield, carotenoids and photosynthetic pigments in stressed plants as compared to control ones. Results showed that salt stress significantly affected the oxidative compounds (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)) and non-oxidative compounds (ascorbic acid, total phenols, malondialdehyde (MDA), proline, and H2O2) in lettuce. Moreover, salt stress decreased nitrogen (N), phosphorous (P), and potassium ions (K+) while increasing Na ions (Na+) in the leaves of lettuce under salt stress. The exogenous application of NO increased ascorbic acid, total phenols, antioxidant enzymes (SOD, POD, CAT, and APX) and MDA content in the leaves of lettuce under salt stress. In addition, the exogenous application of NO decreased H2O2 content in plants under salt stress. Moreover, the exogenous application of NO increased leaf N in control, and leaf P and leaf and root K+ content in all treatments while decreasing leaf Na+ in salt-stressed lettuce plants. These results provide evidence that the exogenous application of NO on lettuce helps mitigate salt stress effects.
