Antioxidant Response to Salinity in Salt-Tolerant and Salt-Susceptible Cultivars of Date Palm

Abstract

The salinity tolerance mechanism in date palm through antioxidation has not been completely deciphered to date. Therefore, this study aimed to investigate the role of various antioxidants in salinity tolerance. Two date palm cultivars, contrasting in salinity tolerance, were used as model plants in a comparative study designed to detect changes in growth, Na+ and K+ uptake, reactive oxygen species (ROS), and antioxidant accumulations, when plants were exposed to salt stress. The results showed that salinity treatment had a more substantial negative effect on the growth and photosynthetic pigmentation of the susceptible ‘Zabad’ cultivar than on the tolerant ‘Umsila’ cultivar, probably due to the ability of ‘Umsila’ to accumulate less Na+ and more K+, to maintain a normal concentration of ROS and to produce more non-enzymatic antioxidants, including glutathione, phenolic compounds, flavonoids, and proline. Under salinity, ‘Umsila’ could also activate more superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) than ‘Zabad’. These results suggest that the tolerance of ‘Umsila’ is partially due to the balanced Na+ and K+ uptake and to the relatively high concentration of ROS-scavenging metabolites. Together, these results indicate that the antioxidant mechanism is crucial for salinity tolerance in date palms. However, other mechanisms may also be involved in this trait.

Comparative Water Relations of Two Contrasting Date Palm Genotypes under Salinity

“…Despite both the leaf OP and root OP was decreased in Umsila and Zabad under salinity, these parameters including LWP were less affected in Umsila, suggesting that this cultivar displayed a higher ability to extract water under saline conditions than salt-sensitive Zabad. is feature can be contributed to the capacity of this tolerant cultivar to lower the osmotic potential (osmotic adjustment) under salinity, likely through the production of sugars as shown in International Journal of Agronomy this report and also other osmolytes such as proline as previously shown [11]. It was previously shown that despite the low water potentials in Atriplex L. under salt stress, it could maintain cell turgor pressure and a favorable water absorption gradient because of the ability of this species to adjust osmotically [78][79][80].…”

“…Determination of salt tolerance mechanism in the date palm requires global omics analysis and rigorous physiological studies [2]. Despite the fact that the association between transcriptomics [7][8][9], metabolomics [10], and biochemical analyses [11][12][13] with salinity tolerance was investigated in the date palm, the importance of physiological parameters including water relations has not been thoroughly studied.…”

“…e lower OP values in the leaf and root tissues could be attributed to the fact that Zabad accumulates higher amounts of Na + than Umsila when grown under salinity. In addition, this reduction in OP might have further contributes toward the reduction LWP which in turn significantly (p < 0.05) affected the RWC of the salt-sensitive Zabab as compared with Umsila [11,12] e overall improved water management system of the salt-tolerant Umsila can be related to the overall genetic makeup of the plant, rendering to its healthy physiology under salinity stress. Also, it was previously shown that transgenic Arabidopsis plants overexpressing the date palm gene, had improved water management under salinity and drought conditions.…”

Alleviation of Detrimental Effects of Salt Stress on Date Palm (Phoenix dactylifera L.) by the Application of Arbuscular Mycorrhizal Fungi and/or Compost

“…The fruits of the date palm are rich in essential nutrients such as sugars, proteins, fibers, minerals, antioxidants, and vitamins (Vayalil, 2012;Kamal-Eldin and Ghnimi, 2018). To date, several studies have analyzed date palm responses to salinity stress (Sperling et al, 2014;Yaish and Kumar, 2015;Meddich et al, 2018;Ait-El-Mokhtar et al, 2019;Al Kharusi et al, 2019) but few have addressed the effects of AMF inoculation in alleviating salt stress in date palms (Meddich et al, 2018;Ait-El-Mokhtar et al, 2019). Furthermore, no study has yet tested the role of the combined application of AMF and compost in the salt tolerance of date palms and the underlying mechanisms.…”

Molecular and phytochemical assessment for some seedy strains of Alamar apricot rootstock under salinity stress

“…In addition, the results obtained by Bolat et al [26] underlined the important role of some antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and compounds in protecting cellular mechanisms during water stress conditions. The increase of SOD, CAT and APX, activity and accumulation increase of non-enzymatic antioxidant reagents such as glutathione, phenolic compounds, flavonoids, and proline could represent a key mechanism for salinity tolerance in plant [27].…”