Synseeds Techniques and its Impact on the Future of Plant Tissue Culture

Abstract

Tissue culture techniques are considered as novel plant biotechnology tools in the past decades because their high potential to establish specific experimental conditions, multiplication in mass production, magnify or control the genetic variation and facilitating the variant selection. Problems of in vitro obtained plant materials retard the investment in micropropagation fields because final products are represented by non-acclimatized plantlets, which require specific managements until final field delivery. To counteract the problems of in vitro techniques, synthetic seed technology should be used especially when seedless plants such as banana or plants with unviable seeds have been subjecting for plant improvement. To create artificial seeds, artificial endosperm around plant materials (somatic embryos, shoot tips or nodal segment) was established by dipping plant materials in gel matrix (MS with 4% sodium alginate). Then, the alginate-covered plant materials were dropped in complexing agent (75 mM CaCl2) for 30 minutes and washed in MS medium. The obtained artificial seeds (synseeds) could be stored in refrigerator for several weeks up to several months with high conversion especially when they stored submerged in MS liquid medium supplemented with low sucrose concentration and growth regulators.

Keywords

Artificial seeds, Banana, RAPD, Micropropagation, Tissue culture

Introduction

Why is Artificial Seeds Essential Perquisite in Banana Plantation?

There are many plant species are highly sterile and producing fleshy and seedless fruits such as banana. In banana, conventional propagation can be fulfilled using corms, large and small suckers, and sward suckers but they carry weevils, fungal pathogens, nematodes and viruses [1]. In addition, traditional plant materials suffer from slow multiplication. Plant tissue culture techniques have great potential to overcome some factors limiting traditional propagation approaches [2-5]. In vitro propagated plant materials show high multiplication rate with homogenous growth, physiological uniformity and the availability of diseasefree plant materials. In fact, micro propagated plantlets are not always satisfactory and not warrant high investment because the final products are represented by non-acclimatized plantlets, which require specific managements until commercialization and final delivery. To reduce the previous problems, synthetic seed should be used as an effective and efficient alternative method in in vitro propagation. Summarized the benefits of synseeds where they facilitate the exchange of sterile plant material between laboratories and direct delivery of plantlets to the field without acclimatization steps. Also, synseeds reduce costs of micropropagated plants and breeding cycle [6-10].

Discussion

Artificial Seeds Production

Synseeds would allow enclosing of small in vitro derived explants inside a nutritive and protective capsule. In banana, sucker shoot tips were multiplied on MS medium supplemented with 5 mg/l BAP for six subcultures to obtain enough shoot tips for production of artificial seeds in large scale. Single layer synseed beads were obtained by dipping shoot tips with forceps in glass jar containing the gel matrix (MS and 4% sodium alginate). Alginate-covered explants were picked up and individually dropped into complexing agent (75 mM CaCl2) for 30 minutes. Transfer time from gel matrix to complexing agent must not exceed five minutes. Beads were washed using MS with growth regulators three times, 5 min/each. The obtained beads (synseeds) were 5-6 mm in diameter and should be handled and stored under sterile conditions to avoid dehydration [11-15].

Conversion of synseeds to plants

Conversion described the production of a green plant with a normal phenotype from a synseed. In contrast to a somatic embryo, which is a bipolar structure, shoots and buds do not able to convert. If the encapsulated plant materials are associated with their inability to form adventitious roots spontaneously, the unipolar micro-cutting such as shoot tip constitutes a great problem for their use in synseeds production. In some species, such as banana, cardamom, mulberry, and raspberry, encapsulated micro cuttings demonstrated a high adventitious rooting capacity after synseed sowing [16-21], but other plant species did not able to establish roots.

Conclusion

In these latter cases, an appropriate root induction treatment should be elaborated via encapsulation of the explants immediately after induction of root formation.

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