Abstract

Date palm (Phoenix dactylifera L.) is one of the most valuable economic resources in the Middle East and North Africa that grow on monocotyledonous trees. To increase crop yield of palm trees, in vitro micro-propagation has become an attractive alternative for large-scale production of date palm. A problem that frequently damages tissues in the early micro-propagation is the brown color that advances in the callus culture due to the creation of quinones. Quinones seize plant cellular developments which lead to cellular decay. This study advocates the use of antioxidant factors found in spinach, kale and strawberries within various concentrations (50, 150 and 300 mg/L) with respect to the medium culture, in an attempt to reduce the level of total phenol and browning which occurs, and also to improve growth and development in different in vitro stages of date palm (P. dactylifera L.). The results indicate that better growth value of callus was achieved using 150 mg/L of kale concentration; allowing the total phenol level to be reduced to 0.9237 mg/g D.W, presenting a significant growth value in comparison to the other treatments in the embryonic callus stage. In the date palm’s somatic embryogenesis stage, the results show that the use of 50 mg/L of spinach, 50 mg/L of kale, 150 mg/L of strawberries, achieved a high number of somatic embryos and the total phenol level was reduced to 0.6167 mg/g D.W. Results from date palm shoot proliferation shows that high numbers of shoot (16.3) was achieved using 50 to 300 mg/L of kale; however, total phenol level was reduced to 0.04567 at 150 mg/L of spinach concentration. The fluctuation of reducing total phenol level in date palm was recorded when the explants were grown on medium supplemented with 50 mg/L of kale concentration.

Key words: Date palm, tissue culture, natural antioxidants, browning, quionones.