Some biochemical changes and activities of antioxidant enzymes in developing date palm somatic and zygotic embryos in vitro

Some biochemical changes and activities of antioxidant enzymes in different developmentalstages of date palm somatic and zygotic embryos were studied in vitro. The levels of endogenous ascorbic acid (AA), dehydroascorbic acid (DHA) and some biochemical components (phenols, flavonoid, free amino acids, proteins, and malondialdehyde (MDA)) and the activities of antioxidant enzymes peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) in the different developing stages of somatic and zygotic embryos of date palm cv. Sewi were determined. Zygotic embryo and also embryogenic callus contained high concentrations of AA (9.48 and 9.13 mg 100 g^-1 f.wt., respectively). While the mature somatic embryos contain the lowest concentration of AA (4.09 mg 100 g^-1 f.wt.), Zygotic embryo contains the highest significant levels of phenols, flavonoid, free amino acids, proteins and MDA. However, the lowest concentrations of phenols and flavonoids were recorded at the embryogenic callus. The POD activity was the highest level at embryogenic callus and then decreased gradually during the subsequent developmental stages, while, the activities of PPO and PAL were the highest levels at zygotic embryos.