Thidiazuron-induced direct organogenesis from immature inflorescence of three date palm cultivars

Rania A Taha,Mai A Allam,S.A.M Hassan,Basem M.M Bakr,Mona M Hassan

doi:10.1186/s43141-021-00115-4

Abstract

BackgroundInflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved. These plant materials are abundantly available every year and can be used as cheap and potent explants. Nevertheless, many difficulties could be faced in this protocol according to selection of the spathe size and age, media components, growth regulators, etc. The aim of this study was to determine the influence of various cytokinins on direct organs induction of three date palm cultivars (Selmi, Barhee, and Medjool) from immature inflorescence. An additional objective of this study was to investigate the effect of cytokinins and auxins on growth and development of Medjool cultivar. ResultsVarious combinations of cytokinins were investigated on three date palm inflorescences as N6-(2-isopentenyl) adenine (2iP), kinetin, benzyleadenine (BA), and thidiazuron (N-phenyl-N′-1,2,3-thidiazol-5-yl urea) (TDZ). TDZ alone or in combination with BA proved to be superior for direct organogenesis in all three cultivars so that another combination of TDZ with BA was conducted. Results showed that moderate concentration of BA, with TDZ, gave superior response. Medjool cultivar response surpassed other two cultivars that made the possibility to conduct some growth regulators treatments on its multiplication and regeneration. TDZ at 0.5 + BA at 1.0 mg/l without activated charcoal seemed to enhance multiplication rate. Medium containing 0.5 mg/l of both naphthaleneacetic acid and indole butyric acid in addition to 1.0 mg/l indole acetic acid appeared to be more suitable for rooting stage of Medjool shootlets. ConclusionIn this study, we created an innovation sequence of growth regulators included in nutrient media for date palm direct organogenesis from inflorescence. Organogenesis has been accelerated from immature inflorescence explants and developed to healthy plantlets which acclimatized in greenhouse.

Highlights

Inflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved
Results show that incorporating BA with TDZ and other growth regulators in the media encourage proliferation as new shoots were accelerated in multiplication stage
Presence, within the explants just underneath the supersized cells where their development is suppressed [33]. It could be observed from our results that the presence of naphthaleneacetic acid (NAA) and indole butyric acid (IBA) with indole acetic acid (IAA) (0.5, 0.5, and 1.0 mg/l, respectively) in rooting media achieved the highest significant root number, root thickness, and hairy root formation on Medjool shootlets compared with IAA alone

Summary

Introduction

Inflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved. These plant materials are abundantly available every year and can be used as cheap and potent explants. The aim of this study was to determine the influence of various cytokinins on direct organs induction of three date palm cultivars (Selmi, Barhee, and Medjool) from immature inflorescence. Date palm (Phoenix dactylifera L.) is a dioecious, perennial monocot plant species that belongs to family Arecaceae. Date palm micropropagation has been performed with induction of indirect somatic embryogenesis. Long time is required for the initiation phase, moderate multiplication rate is achieved and the strong influence of the variety is limiting the rate of micropropagation [6]

Objectives

Methods

Results

Discussion

Conclusion