Artificial Seed Production 4q4jc

ARTIFICIAL SEED PRODUCTION

Presented by Joshua Samuel I M.Sc. Biotechnology DR.G.R.D.C.S

ARTIFICIAL SEEDS What is a seed ? A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant.(According to Wikipedia) What are artificial seeds ? Synthetic or artificial seeds have been defined as somatic embryos engineered for use in the commercial propagation of plants (Gray and Purohit, 1991; Redenbaugh, 1993).

Artificial Seeds Types of synthetic seeds : Types of synthetic seeds Hydrated synthetic seeds (Redenbaugh et. al., 1986) Desiccated synthetic seeds (Kitto and Janik, 1985)

Natural Seeds (Lotus seeds)

Why artificial seeds over natural ?? Storage Life Much longer, seed viability remains good for longer time period. Product uniformity As somatic embryos used are genetically identical. Large scale propagation Very much suitable for large scale monoculture. Germplasm conservation Important in germplasm conservation. Permits direct field use

Facilitates study Of seed coat formation, function of endosperm in embryo development and seed germination, somaclonal variation. Supply of beneficial adjuvents beneficial adjuvants like plant nutrients, plant growth regulators, microorganisms, fungicides, mycorrhizae, antibiotics can be made available to the developing plant embryo as per the requirement as these can be added in to the matrix.

Hybrid production synthetic seed production technology can be used for production of hybrids which have unstable genotypes or show seed sterility. It can be used in combination with embryo rescue technique. The rescued embryo can be encapsulated with this technique.

Artificial Seeds production (Summary)

 Induction of somatic embryogenesis.  Maturation of somatic embryos.

 Encapsulation of somatic embryos.  Evaluation of embryoids and

 Conversion Planting in fields / green house.

Somatic embryogenesis Somatic cells Somatic or vegetative cells are derived from the Greek word for “body”. Somatic cells are diploid in nature. Embryogenesis Formation of an embryo Somatic Embryogenesis Is the process by which the somatic cells or tissues develop into differentiated embryos and each fully developed embryo is capable of developing into plantlet. In vitro process , by which somatic cells develop into somatic embryo without gametic fusion Types of Somatic Embryogenesis Direct and Indirect Embryogenesis.

Stages of Somatic Embryo Globular Stage or phase.

Heart shaped stage or phase.

Torpedo stage or phase.

Cotyledonary stage or phase.

Gelling agents used in artificial seed production Several agents like agar, alginate, plyco2133(Bordon Co.), carboxy mathyl cellulose, carrageenan, gelrite(Kelko Co), guargum, sodium pectate, tragacanth gum etc Out of these gelling agents alginate was found to be more suitable for artificilal seed production Why alginate gel ? Alginate hydrogel is frequently selected as a matrix for synthetic seed because of its moderate viscosity and low spinnability of solution, low toxicity for somatic embryos and quick gellation, low cost and bio-compatibility characteristics Alginate was chosen because it enhances capsule formation and also the rigidity of the alginate beads provides better protection to encased somatic embryos against mechanical injury

Principle and Conditions for encapsulation with Alginate matrix Biochemistry Alginate is a straight chain, hydrophilic, colloidal poluronic acid composed primarily of hydro-beta-D-mannuronic acid residues with 1-4 linkages. Principle The major principle involved in the alginate encapsulation process is that the sodium alginate droplets containing the somatic embryos when dropped into calcium chloride solution form round and firm beads due to ion exchange between Sodium in sodium alginate and Calcium in calcium chloride solution. The hardness and rigidity of the capsule mainly depends upon the number of sodium ions exchanged with calcium ions. In general 3% sodium alginate upon complexation with 75mM calcium chloride for half an hour gives optimum bead hardness and rigidity for the production of viable synthetic seed

Artificial Endosperm: Somatic embryos lack seed coat (testa) and endosperm that provides nutrition and protection for zygotic embryos in developing seeds. To augument these deficiencies, addition of nutrients and growth regulators to the encapsulation matrix is desired, which serves as an artificial endosperm. Addition of nutrients and growth regulators to the artificial matrix results in increase of germination and viability of encapsulated somatic embryos. These synthetic seeds can be stored for a longer period of time even up to 6 months without losing viability, especially when stored at 4◦C.

Addition of Adjuvents to the matrix In addition to prevent the embryo from desiccation and mechanical injury, a number of useful materials such as nutrients, fungicides, antibiotics and microorganisms may be incorporated into the matrix. Incorporation of activated charcoal improves the conversion and vigour of the encapsulated somatic embryos Why charcoal ? Charcoal breaks up the alginate and thus increases respiration of somatic embryos. Charcoal retains nutrients within the hydrogel capsule and slowly releases them to the growing somatic embryo.

Utilization of artificial seeds

Multiplication of non-seed producing plants The artificial seed system can also be employed in the propagation of male and female sterile plants for hybrid seed production. Cryopreserved artificial seeds may also be used in germplasm preservation particularly in recalcitrant species.

Terminology

Germplasm conservation: The sum total of all the genes present in a crop and its related species constitutes its germplasm. It is ordinarily represented by a collection of various strains and species. Somaclonal variation:It is the term used to describe the variation seen in plants that have been produced by plant tissue culture. Chromosomal rearrangements are an important source of this variation. Spinnability of a solution the capacity of a viscous liquid to be drawn out into a strand or blown up into a bubble.

References • http://en.wikipedia.org/wiki/Seed • http://www.uoguelph.ca/plant/research/embryo/synse eds.htm • http://theagricos.com/tissue-culture/artificialseeds/advantages-of-artificial-seeds/ • http://www.wiziq.com/tutorial/57248-synthetic-seed • http://biobasics.gc.ca/english/View.asp?x=799

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