High-frequency direct somatic embryogenesis and plantlet regeneration from date palm immature inflorescences using picloram

Abstract

Background Date palm (Phoenix dactylifera L.) is a traditional crop in arid and semi-arid areas. Its vegetative propagation can be achieved by offshoots, but possible number of offshoots in mother palm trees is limited. Micropropagation is a highly recommended strategy for obtaining date palm elite cultivars using shoot tip and immature inflorescences. In this study, micropropagation procedure using inflorescence explants of Medjool cv. is described. For culture initiation, explants from different spathe lengths were cultivated on Murashige and Skoog medium (MS) supplemented with picloram at 1.0 and 2.0 mg/l combined with 2iP at 0.5 mg/l alone and with both 2iP and BA at 0.25 mg/l for 24 weeks. The obtained direct globular embryos were transferred to maturation media with 0.1 mg/l picloram alone or combined with both 2iP and ABA separately and together for further development. Additionally, multiplication and rooting media were optimized by different cytokinins and auxins for high frequency of plantlet production. Acclimatization of in vitro plantlets was also investigated. Results The highest percentage of globular embryo formation was noticed with explants isolated from spathe lengths ranging from 10 to 15 cm. Addition of BA to initiation media with picloram encouraged a significant effect on embryonic culture formation percentage. Incorporation of ABA and 2iP to maturation medium was an effective factor for individual or multiple embryo emergence. Acclimatization of in vitro plantlets having 3–4 roots was successfully accomplished. Irrigation with the full strength solution (MS) encouraged the highest growth vigor degree, leaf number/plant, leaf width, root number, and root thickness degree of ex vitro plants. Conclusion This research provides an advanced regeneration system for large-scale production of date palm from immature inflorescences of Medjool cv. It opens up the prospects of using picloram with different growth regulators for rapid micropropagation of date palm.

Somatic embryogenesis and plant regeneration from transverse thin cell layers of adult peach palm (Bactris gasipaes) lateral offshoots

“…This phase has been considered a bottleneck for plant micropropagation ( Hassan et al, 2014 ), particularly in peach palm ( Steinmacher et al, 2007c ). Acclimation could be improved by supplementing the substrate with MS nutrients and by immersing the roots in fungicide solutions, as was done in date palm ( Hassan et al, 2021 ). The results presented in this work are very promising, as they demonstrate the feasibility of mass propagation of adult peach palm elite plants from lateral offshoots by somatic embryogenesis from transverse TCL explants.…”

In vitro embryo formation and plantlet regeneration from unpollinated ovaries of Lilium L

“…Picloram was also used in this experiment. It is reported that adding BA to the starting medium containing picloram can significantly promote the formation of embryos (Hassan et al., 2021). In this experiment, different concentrations of picloram were used.…”

In vitro propagation for conservation of the rare date palm (Phoenix dactylifera L.) ‘Amri’ using immature inflorescence

“…The rooting medium comprised full-strength solid MS medium containing 0.5 mg L −1 NAA, 1.0 mg L −1 IBA, 0.1 mg L −1 paclobutrazol (PBZ; Sigma-Aldrich), 30 g L −1 sucrose, 2.0 mg L −1 glycine, 5.0 mg L −1 thiamine HCl, and 1.0 mg L −1 biotin. The medium, solidified with 7.0 g L −1 Agargel™, every 25-mL medium was poured into (2.5 × 25 cm) culture tubes, one for each shoot, and the shoots were incubated for 12 wk (refreshed every 6 wk) to produce roots at 27 °C ± 2 °C with a light intensity of 4000 lx (Hassan et al 2021). After the rooting stage, the rooted shoots were transplanted to halfstrength liquid MS medium with the same other compositions of rooting medium for a 6-wk pre-acclimatization stage, with incubation in the same conditions.…”