In vitro propagation of the endangered date palm (Phoenix dactylifera L.) cv. Ghazal: 2- Improvement of germination and development of embryos by silver nitrate and silver thiosulfate

Abstract

Date palm (Phoenix dactylifera L.) is one of the most importan tree crops in the deserts which is a tree high economic and commercial values. This study was performed to micro propagate of date palm cv. Ghazal via somatic embryogenesis. Although, it was conducted to examine different concentration of silver nitrate (SN) and silver thiosulfate (STS) for their effect on somatic embryogenesis development of date palm. In this context, the obtained results indicated that, all silver treatments, whether nitrate or thiosulfate, had a positive effect. The highest number, length and growth value of somatic embryos formed are obtained from embryogenic celli cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg/l SN or 1.0 ml/l STS. Moreover, the results have shown that the SN at 4.0 mg/l or 2.0 ml/l promoted the growth, proliferation, maturation and germination of somatic embryos of date palm. 80 and 82.2% of embryos had differentiated and germinated to plantlets when re-cultured on the same previously medium. While, the medium supplied with full - strength MS medium with 1.0 mg/l IBA and 1.0 mg/l SN or 0.5 ml/l STS showed superiority in the number of roots and their length in comparison with the other treatments. High frequencies of survival rates in greenhouse conditions were obtained after acclimatized and transferred to pots containing a mixture of peat moss and perlite at equal volume. Accordingly, these results suggest that adding silver nitrate or silver thiosulfate to the culture medium of date palm cv.Ghazal may be beneficial to improve the somatic embryogenesis growth performance and their developed for this cultivar.