In vitro somatic embryogenesis and plantlet regeneration from immature male inflorescence of adult dura and tenera palms of Elaeis guineensis (Jacq.)

Abstract

We report here a method for plant regeneration through somatic embryogenesis from explants collected from immature male inflorescence of adult oil palm cultivated in India. Callus induction was successful from tissues of immature male inflorescence collected from both dura and tenera varieties of oil palm. A modified Y3 (Eeuwens) media supplemented with several additives and activated charcoal (3%) were used for the experiments. Out of four different auxin treatments, 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid (picloram) produced maximum callus induction (82%) and it was not significantly different from 2,4-dichlorophenoxyacetic acid (2,4-D) and a combination of 2,4-D + picloram. The callus induction obtained with auxin α-naphthalene acetic acid was only 54% and it was significantly low as compared to the other treatments. Highest embryogenesis was obtained with a combination of 2,4-D + picloram (4.9%) followed by picloram (3.4%). Genotypic variation in response to the same auxins was observed both for callus induction and embryogenesis. Callus induction and embryogenesis ranged from 42 to 72% and 6.8 to 9.35%, respectively in tenera. The formation of embryogenic calli was marked by the appearance of white to yellowish globular or nodular structures which subsequently formed clear somatic embryos. Somatic embryogenesis was asynchronous and at one time we could find different stages of embryogenesis like the globular, torpedo and the cotyledonary stages. The somatic embryos when exposed to light in the same basal media along with 6-benzyladenine (18 µM), abscisic acid (3.78 µM) and gibberellic acid (5.78 µM) regenerated into plantlets. To the best of our knowledge this is the first report o f callus induction and somatic embryogenesis from immature male inflorescence of oil palm.

High-Efficiency Somatic Embryogenesis from Seedlings of Koelreuteria paniculata Laxm.

“…This result may indicate that low concentrations of NAA were suitable for SE in K. paniculate. In the studies of other woody plants, the frequency of somatic embryogenesis varied from 4.9% to 63% [27][28][29]34], and the frequency of SE in K. paniculate was at a high level in the research. Similarly, NAA has been reported to influence somatic embryo development in holm oak and Eucalyptus camaldulensis Dehn.…”

“…In addition, studies about the effects of 2,4-D and other PGRs on embryogenic callus induction were reported. In the study about Elaeis guineensis, 2,4-D was proved to have similar effects on embryogenic callus induction to picloram [27], and similar results were also obtained in oil palm [31]. For SE, some studies showed that high 2,4-D concentrations are conducive to embryogenic callus induction and proliferation, and that the reduction or removal of 2,4-D promotes SE [32,33]; however, conflicting results were reported.…”

“…The highest induction rate (80.25%) was obtained on DKW medium supplemented by 0.5 mg L −1 BA, 0.25 mg L −1 NAA, and 1.5 mg L −1 2,4-D, which was similar to the study performed in Elaeis guineensis Jacq. [27]. Inappropriate PGR concentrations led to browning and rhizogenesis.…”

“…[28,35]. In the study about Elaeis guineensis, the ability of NAA to promote somatic embryo development is poor compared with other PGRs [27]. Moreover, other PGRs, such as strigolactone and picloram, have been used to enhance SE in other plants [21,[36][37][38], and picloram performed better than NAA in Eucalyptus species [17].…”

Somatic embryogenesis from zygotic embryos and thin cell layers (TCLs) of Brazilian oil palm (Elaeis guineensis Elaeis oleifera)

“…In the case of E. guineensis, several types of explants were already used to initiate somatic embryogenesis process: Mature or immature zygotic embryos (Balzon et al, 2013;Silva et al, 2014), cell suspensions from immature leaf segments (De Touchet et al, 1991), leaf segments (Pádua et al, 2013) and immature male inflorescence (Jayanthi et al, 2015).…”