Effect of potassium nitrate on antioxidants production of date palm (Phoenix dactylifera L.) in vitro.

Antioxidants present in dates are necessary for all physiological processes of humans and animals. In Saudi Arabia date palm is a national fruit tree, produces millions of tons of dates for consumption and is considered a major source of antioxidants. The main aim of this study was to determine the role of potassium nitrate (KNO3) in the formation of antioxidants from explants collected from date palm cultivars in Al-Ahsa Oasis, Kingdom of Saudi Arabia (KSA) and to monitor the extent of its effect on growth and development of cells during callus formation stage via somatic embryogenesis. The results showed that full concentration of KNO3 was the best for callus formation in general. While, the half concentration of KNO3 played an important role for stimulating the explants to form phenolic compounds and the browning emergence for all the cultivars under investigation. On the other hand, the chemical analysis for measuring the phenolic compounds in the explants showed that all the explants formed antioxidants but with varying degrees. The highest mean of phenolic contents was found in those explants cultured with the half concentration of KNO3 for Shishi cv 2.053 ± 0.010a mg g(-1) and antioxidant activity by ABTS Inhibition and UM Trolox was 80.694 ± 0.439 and 801.575 ± 2.391, respectively.