ABSTRACT
Understanding the response of date palm (Phoenix dactylifera L.) cultivars to salt stress is essential for the sustainable management of phoeniculture in Tafilalet, Morocco. It offers a promising avenue for addressing the challenges presented by the increasing salinity of irrigation waters, especially because farmers in these regions often lack the necessary knowledge and resources to make informed decisions regarding cultivar selection. This study addresses this issue by investigating the performance of the most relied on cultivars by farmers in Tafilalet, namely Mejhoul, Boufeggous, Nejda, and Bouskri. These cultivars were exposed to a sodium chloride treatment of 154 mM, and their performances were evaluated over a three-month period. We examined the growth rate, photosynthesis-related parameters, pigments, water status in plants, and biochemical compounds associated with oxidative stress, osmotic stress, and ionic stress. Principle component analysis (PCA) effectively categorized the cultivars into two distinct groups: salt-sensitive (Mejhoul and Nejda) and salt-tolerant (Boufeggous and Bouskri). These findings provide valuable insights for farmers, highlighting the advantages of cultivating Boufeggous and Bouskri cultivars due to their superior adaptation to salt conditions. These cultivars exhibited moderate decrease in shoot growth (25%), enhanced catalase activity, a smaller increase in anthocyanin content, and greater enhancement in organic osmolytes compared with salt-sensitive cultivars like Mejhoul (experiencing an 87% reduction in shoot elongation) and Nejda (exhibiting the highest reduction in leaf area). Furthermore, the Na+/K+ ratio was positively influenced by salt stress, with Mejhoul and Nejda recording the highest values, suggesting its potential as an indicator of salt stress sensitivity in date palms.
ABSTRACT
The effects of major mineral salts, L-glutamine, myo-inositol and carbon source on shoot bud proliferation of date palm (Phoenix dactylifera L.) cv. Mejhoul were evaluated. Different concentrations of ammonium nitrate (NH4NO3; 550, 825 or 1650 mg/L), potassium nitrate (KNO3; 633.3, 950 or 1900 mg/L), calcium chloride dehydrate (CaCl2·2H2O; 147, 220 or 440 mg/L), potassium dihydrogen phosphate (KH2PO4; 57, 85 or 170 mg/L), magnesium sulfate heptahydrate (MgSO4·7H2O; 123, 185 or 370 mg/L), L-glutamine and myo-inositol (0.5, 1, 1.5 and 2 g/L), sucrose, sorbitol, mannitol or commercial granulated sugar (10, 20, 30, 40 or 50 g/L) were tested. The highest number of shoot buds per explant (18.7) occurred on the medium containing 825 mg/L NH4NO3, 1900 mg/L KNO3, 220 mg/L CaCl2·2H2O, 170 mg/L KH2PO4, 370 mg/L MgSO4·7H2O as well as 1 g/L L-glutamine, 2 g/L myo-inositol and 30 g/L sucrose. The results showed that the frequency of hyperhydricity significantly increased in media containing 1650 mg/L NH4NO3. The concentrations of L-glutamine, myo-inositol and carbon source significantly affected the number of shoot buds per explant. However, they had no effect on hyperhydricity, tissue browning and precocious rooting. Shoots of 4.5-6.0 cm in length were isolated and transferred onto hormone-free media for elongation and rooting. After 3 months, the developed plantlets were successfully transplanted in a glasshouse and over 90 % survived acclimatization.
