In vitro plant regeneration system for date palm (Phoenix dactylifera L.): effect of chelated iron sources

Iron chelate sources and their concentrations are important factors in in vitro propagation of date palm. This study's objective was to investigate the effect of the iron chelated form on the growth and development of tissue cultures of Barhee cultivar.

The addition of FeEDDHA to the culture medium was more effective than FeEDTA on callus growth, shoot regeneration, and the number of shoots per jar, where the best result (220.8mg callus, 86.67% and 17.2 shoots per jar, respectively) was obtained by using 93.5 mg L^-1 FeEDDHA (5.6 mg L^-1 Fe), compared with other treatments. The results also indicate that using 93.5 mg L^-1 FeEDDHA (5.6 mg L^-1 Fe) as a supplement can decrease antioxidant enzymes CAT and POD activity compared to the rest of the treatments. Medium equipped with 187.0 mg L^-1 FeEDDHA (11.2 mg L^-1Fe) had the highest rooting percentage and number of roots per shoot than other treatments. The biochemical analysis results showed that treatments with FeEDDHA of 280.5 mg L^-1 (16.8 mg L^-1 Fe) and 187.0 mg L^-1 (11.2 mg L^-1Fe) significantly increased the iron content. The results showed that shoot maximum chlorophyll and endogenous IAA level content were recorded in a medium supplemented with 187.0 mg L^-1 FeEDDHA (11.2 mg L^-1Fe) as Fe source.

FeEDDHA used in the present study was proven to be a promising iron chelate source in comparison with the FeEDTA sources.