Combined efficiency of iron nanoparticles (IONPs) and salicylic acid (SA) on in vitro propagation of date palm (Phoenix dactylifera L.) under combined drought and salinity
Ahmed Madi Waheed Al–Mayahi
Abstract
• It provides experimental evidence for IONPs with SA, in proliferation pathways, and physiological traits. • The use of IONPs and SA together is more effective in enhancing drought and salt tolerance. • The protective role of IONPs and SA by increasing SOD and APX , and accumulation of solutes. • Using IONPs and SA creates additional protein bands, providing a reason to withstand stresses. Drought and salinity are the most important environmental factors that hamper agricultural productivity worldwide. Several adaptations and mitigation strategies are needed to deal with both stresses. The objective of the study was to determine the effect of the iron nanoparticles (IONPs) and salicylic acid (SA) under combined drought and salt stresses (DS) (PEG6000 + NaCl) on growth and some biochemical constituents of date palm cv Barhee cultured in vitro . The optimal combination was 1 mg L −1 IONPs and 50 mg L −1 SA. Such a combination under DS improved the callus growth and increased its weight to 219 mg. This combination also showed the highest response rate and the number of shoots per jar (55.65% and 6.80, respectively). The addition of IONPs and SA to the medium was most effective on the contents of organic solutes (soluble sugar, soluble protein, and proline), where the best results (4.213, 2.37, and 1.42) mgg −1 respectively, were obtained using 1 mg L −1 IONPs and 50 mg L −1 SA application under DS. This combination was also more effective under DS in increasing the chlorophylls, as well as K and Fe. Additionally, the 1 mg L −1 IONPs and 50 mg L −1 SA application under DS resulted in increasing the activities of antioxidant enzymes SOD and APX, to 31.9 and 3.28 unit −1 min −1 respectively, compared to the other treatments. On the contrary, a combined application of 1 mg L −1 IONPs and 50 mg L −1 SA countered DS-induced damage by reducing levels of Malondialdehyde (MDA), Hydrogen Peroxide (H 2 O 2 ), and Na in stressed plants to (0.88,1.71) µMgFw −1 , and (1.688) mgg −1 DW, respectively. The SDS-PAGE protein detection indicated changes in the amount and number of protein bands. New protein bands appeared in both stressed with IONPs and SA-treated plants. Based on the current study, the combined application of IONPs and SA is an effective strategy that can be used to enhance the combined drought and salt stress tolerance of date palm plants.