Role of darkness in the germination process and conversion of direct somatic embryos into plantlets: Micropropagation protocol enhancement study of date palm.

Abstract

All studies in date palm somatic embryogenesis focused on the germination of light and neglected the darkness effect on germination. Study of the effect of light and darkness incubation on germination of date palm somatic embryos led to the developing of an efficient new and simple procedure for inducing the direct date palm somatic embryos germination and conversion into plantlets. In vitro germination in darkness played a critical role in direct converting date palm somatic embryos into plantlets. Direct somatic embryos germinated in the darkness exhibit continuous growth leading to forming etiolation longitudinal stems and thin leaves, while somatic embryos germinated in the light show inhibition of longitudinal growth with the formation of short stems and green wide leaves. Darkness germination process had decreased significantly the conversion period of direct somatic embryos into plantlets to less than 12 weeks. Darkness incubation led to germination and elongation in one stage, while the incubation in the light required two stages the embryo germination stage then the elongation stage. Somatic embryos grown in darkness had more protein and less phenolic compounds than embryos grown in the light. These results had led to significantly decrease in the protocol period and modified the protocol stages of date palm somatic embryos germination and conversion into plantlets, ending with better germination and reduction of time and costs.

Effect of dark incubation in germination of indirect date palm somatic embryos and conversion into plantlets

“…Recently only study the effect of light conditions on germination and conversion of indirect date palm somatic embryos to plantlets, the darkness significantly stimulated the conversion of somatic embryos to plantlets. (Abohatem et al 2020). The effect of light intensity and type on organogenesis has been only studied in date palm (Al-Mayahi 2016;Meziani et al 2015).…”