GOOD MORNING

Presented byMD.MAHTAB

M.Sc. BIOTECH 3rd SEM.

Jamia Hamdard

SYNTHETIC SEEDS:A NEWCONCEPTION IN SEED

BIOTECHNOLOGY

Artificial seeds were first introduced in the 1970s as a novel analogue to the plant seeds.

The idea of synthetic seeds was first conceived by Murashige which was subsequently developed by several investigator.

The production of synthetic seeds for the first time by KITTO and JANICK involve encapsulation of carrot Somatic Embryos(SEs) followed by their desiccation.

Especially useful for plants which do not produce viable seeds.

Artificial seeds are small sized and this provides further advantages in storage, handling, shipping and planting.

INTRODUCTION

ARTIFICIAL SEEDS= SYNTHETIC SEEDS

Synthetic seeds are seed like structures derived from somatic embryo under in-vitro conditions after encapsulation by

hydrogel.

ARTIFICIAL SEEDS

ARTIFICIAL PLANT SEED PRODUCTION

PLANT SEEDS What is it?A plant seeds consist of an embryo and its food store (endosperm), surrounded by seed coat (testa).The seeds ensure that next generation of plant exists.

THE EMBRYO The embryo is made up of two or

more cotyledons attached to a central axis.

The upper part of the axis contain plumule at its tips. The plumule grows into the shoot tips. The lower part of the axis consists of hypocotyl and redicle. The redicle grows into the root system.

ARTIFICIAL PLANT SEED PRODUCTION

The Testa Testa protects the embryo from injury and drying

out. It also make sure that the embryo remains viable

before germination. As germination occurs, water is observed and the seed coat break allowing the redicle to first emerge from the seed.

THE ENDOSPERM The endosperm is the food reserve that the embryo

uses during the early stages of germination. Before the embryo is able to produce its own food

through photosynthesis, the endosperm provides vital nutrients to the embryo.

ARTIFICIAL PLANT SEED PRODUCTION

HYDRATED ARTIFICIAL SEEDS

(Redenbaugh et al., 1986)

DESICCATED ARTFICIAL SEEDS (Kitto and Janik, 1985)

TYPES OF ARTIFICIAL SEEDS

Somatic embryos are enclosed in gels, which remain

hydrated.

Calcium alginate is most suitable.

Hydrated artificial seeds are sticky & difficult to

handle on a large scale & are dry rapidly in the open

air .

This problems can be solved by providing a waxy

coating over the bead.

However, hydrated artificial seeds have to be planted

soon after they are produce.

Redenbergh et.al(1986) develop hydrated artificial

seeds by mixing SE of alfalfa, celery & cauliflower with

sodium alginate followed by dropping into a solution

of calcium chloride/nitrate to form calcium-alginate

HYDRATED ARTIFICIAL SEEDS

SE’s is 1st hardened to withstand desiccation & then are encapsulated in suitable coding material .

SEs may be hardened either by treating/coating mature SE with suitable polymer followed by treated with ABA (improve germination of SE).

Kitto & Janik 1st developed desiccated artificial seeds from SE of carrot.(5% solution of polyethylene oxide (polyox WRS N-750))

DESICCATED ARTFICIAL SEEDS

SEs are bipolar structure which have both apical and basal meristematic regions, which are capable of forming shoot and root respectively.

A plant derived from SEs is some time referred to as an Embling.

SEs are formed from plant cells that are not normally involved in the development of embryos, i.e ordinary tissue.

No endosperm or seed coat is formed around a somatic embryo.

SEs embryo possess the radical and plumule that are able to develop into root and shoot in one step usually without any specific treatment.

What are somatic embryos ?

DROPING METHOD Synthetic seeds can be produced by encapsulating shoot buds

or somatic embryos that have been grown aseptically in tissue culture.

The encapsulation matrix is a hydrogel made of natural extracts from seaweed (agar, carageenan or alginate), plants (arabic or tragacanth), seed gums (guar, locust bean gum or tamarind) or microorganisms (dextran, gellan or xanthan gum).

These compounds will become gel when mixed with or dropped into an appropriate electrolyte (copper sulphate, calcium chloride or ammonium chloride).

Ionic bonds are formed to produce stable complexes. Useful adjuvant such as nutrients, plant growth regulators, pesticide and fungicide can be supplied to the plant propagules within the encapsulation matrix.

STEPS OF SYNTHETIC SEEDS PRODUCTIONHydrated system for artificial seed production

Water insoluble ,gelatinous, cream coloured substance produced through the addition of aqueous calcium chloride to aqueous sodium alginate.

Calcium Chloride + Sodium alginate = Calcium alginate

Alginate is the term usually used for the salts of alginic acid.

Alginate is present in the cell wall of brown algae as the calcium, Magnesium and sodium salts of alginic acids.

Plant embryos trapped in calcium alginate beads.

Calcium alginate

The somatic embryo is encapsulated in Calcium alginate beads.

Desiccated system for artificial seed production

Molding method

This method follows simple procedure of mixing of embryos with temperature dependent gel (e.g. gel rite, agar).

Cells get coated with the gel at lowering of the temperature.

1.Synthetic seeds of

Mulberry planted in soil.

2.Mulberry synthetic

Seeds germinating into plantlet into soil.

3. Completeplantlets of banana obtained from synthetic seeds.

Can be directly grown into field Or It can placed in autoclaved soil in petridish.

Soil : soil rite : Quartz -1:1:1

After that placed in green house from where it can planted in field.

GERMINATION OF SYNTHETIC SEEDS

Alginate hydro gels are frequently selected as a matrix of synthetic seeds because of its moderate viscosity & low toxicity for SE & quick gellation & low cost.

AGAR is considered inferior to alginate with respect to long term storage.

Alginate choosen because it enhance capsule formation & protect SE’s against mechanical injury

WHY ALGINATE WHY NOT AGAR ?

Reduced cost of transplants. Direct greenhouse and field delivery of :-

- elite, select genotypes

- hand -pollinated hybrid

- genetically engineered plant

- sterile and unstable genotype Large- scale mono cultures Mixed genotype plantation

Carrier for adjuvant such as microorganisms, plant growth

regulator pesticide, fungicide, nutrients and antibiotics. Protection of mieotically- unstable, elite genotype.

Why should we be interested ?

Used in multiplication of non-seed producing plant, ornamental hybrid or the propagation of polyploid plant with elite trait.

Using SEs it maintain the original genotype of transgenic plant.

Cryopreserved synthetic seeds may also be used for germplasm conservation, particularly in recalcitrant species(like mango cocoa and coconut) as these will not undergo desiccation.

SEs is the potential tool in the genetic engineering of plant , potentially a single gene can be inserted into a somatic plant.

Synthetic seeds produced in Tissue culture are free of pathogen.

Transport of pathogen free propagules across the international borders avoiding bulk transportation of plants quarantine and spread of disease

Utilization of synthetic seeds

Limited production of viable micropropagation.

Improper maturation of SE that makes them inefficient for germination and conversion into normal plants. Limited production of viable micropropagule useful in synthetic seeds production.

Anomalous and synchronous division of somatic embryo.

Lack of dormancy and stress tolerance in somatic embryo that limit the storage of synthetic seeds

LIMITATIONS

The first requirement for the practical application of the synthetic seed technology is the large scale production of high quality micropropagule , which is at present a major limiting factor.

Additional factors responsible for poor germination of synthetic seeds are the lack of supply of nutrients and oxygen, microbial invasion, and mechanical damage of somatic embryos.

One of the future usage of synthetic seeds would be in germplasm conservation through cryopreservation. Either hydrated calcium alginate based or desiccated polyoxyethylne glycol-based synthetic seeds might be used, but it is likely that some degree of drying before cryopreservation would be beneficial.

The synthetic seed technology offers tremendous potential in micropropagation and germplasm conservation, however further research is needed to perfect the technology so that it can be used on a commercial scale.

CONCLUSION

Refrences

1. Capuano, G., Piccioni, E. and Standardi, A., J. Hortic. Sci. Biotechnol., 1998, 73, 299–305. 2. Gray, D. J. and Purohit, A., Crit. Rev. Plant Sci., 1991, 10, 33– 61. 3. Janick, J., Kim, Y.-H., Kitto, S. and Saranga, Y., in Synseeds (ed. Redenbaugh, K.), CRC Press, Boca Raton, 1993, pp. 12–34. 4. Mckersie, B. D. and Bowley, S. R., in Synseeds (ed. Reden- baugh, K.), CRC Press, Boca Raton, 1993, pp. 231–255. 5. Redenbaugh, K., Fujii, J. A. and Slade, in Synseeds (ed. Reden- baugh, K.), CRC Press, Boca Raton, 1993, pp. 38–46. 6. Redenbaugh, K., HortSci., 1990, 25, 251–255 7. Redenbaugh, K. and Walker, K., in Plant Tissue Culture: Appli- cations and Limitations (ed. Bhojwani, S.), Elsevier, Amster- dam, 1990, pp. 102–135. 8. Kitto, S. K. and Janick, J., HortSci., 1982, 17, 488. 9. Kitto, S. and Janick, J., J. Am. Soc. Hortic. Sci., 1985, 110, 277. 10. ibid, 283.

11. Redenbaugh, K., Nichol, J., Kossler, M. E. and Paasch, B., Invitro, 1984, 20, 256–257.

12. Ara, H., Jaiswal, U. and Jaiswal, V. S., Plant Cell Rep., 1999,19, 166–170.

13. Molle, F., Dupius, J. M., Ducos, J. P., Anselm, A., Crolus, S. I, V. and Freyssinet, G., in Synseeds (ed. Redenbaugh,K.), CRC Press, Boca Raton, 1993, pp. 257–270.

14. Bapat, V. A. and Rao, P. S., Plant Cell Tissue Org. Cult., 1990,20, 69–70.

15. Ganapathi, T. R., Suprasanna, P., Bapat, V. A. and Rao, P. S., Plant Cell Rep., 1992, 11, 571–575.

16. Redenbaugh, K. (ed.), Synseeds, CRC Press, Boca Raton, 1993. 17. Jain, S. M., Gupta, P. K. and Netwon, R. J., Somatic Embryo-

genesis in Woody Plants, Kluwer Academic Publishers,Dordrecht, 1995.

18. Gray, D. J., HortSci., 1987, 22, 810–814. 19. Senaratna, T., Mckersie, B. D. and Bowley, S. R., Plant Sci.,64.

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