Introduction to organ culture in Plant tissue culture and root culture.

By, Mithil ShettyM.Sc biotechnology ,D.Y. Patil biotechnology & bioinformatics Insistute, Pune

Organ culture: It is in vitro culture and maintenance of an

excised organ primordia or whole or part of a organ in a way that may allow differentiation and preservation of the architecture and function.

HISTORY: W. Kotte and W. J. Robbins (1922)- reported the 1st culture of

excised root tips from germinated wheat seedlings.

P. R. White (1930)- reported the successful culture of root segments of ascetically germinated tomato seedlings.

C. D. LaRue (1942)- reported first the in vitro culture of excised flower buds of Kalanchoe globulifera and Nemesia strumosa.

S. W. Loo (1945)- reported the culture of shoot tips of Asparagus seedlings on a medium.

L. L. Jansen and J. Bonper (1949)- grew the ovaries of Lycopersicon pimpinellifolium on medium.

J. P. Nitsch (1949-51)- successfully cultured the ovaries of Lycopersicon esculentum, cucunis anguria, Phaseolusvulgaris, Fragaris sp. and Nicotinia tabacum.

N. Maheshwari (1958)- isolated ripe pollen and ovules of Papaver somniferum and cultured them together and thus observed all stages from pollen germination, through fertilization to developments of mature seeds.

E. Galun, Y. Yung and A. Lang(1962-63)- tested the effect of IAA and gibberellin acid 3 upon the expression of culture of isolated floral buds of Cucumis sativus.

G. Morel(1952-53)- showed that through aseptic culture of stem tips the certain virus infections can be eliminated from potato and dahlia, which allowed recovery of healthy plants and also discovered the rapid multiplication of tropical orchid Cymbidium using apical meristem culture.

T. A. Steeves and I. M. Sussex (1966)- first said that culture of excerised leaf primordia would provide an experimental system to study the complete development of leaves under controlled conditions.

Types of organ culture:

Vegetative organs.1. Root culture.2. Leaf culture.3. Shoot-tip culture.

Reproductive organs1. Complete flower culture.2. Isolated ovary culture.3. Isolated ovule and

embryo culture.

Importance of organ culture:

Provide an excellent experimental system to define the nutrients and growth factors.

Study of morphogenesis. Study of secondary metabolites and its biosynthesis. Lead to new developments in agriculture and

horticulture.

ROOT CULTURE:

Root culture is culturing of excised radical tip of aseptically germinated seed in the liquid medium to grow independently under controlled conditions.

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Figure: Root and its important parts

Important parts and function of plant root system:

Root hair - extension of specialized root epidermal cells increasing the surface area for adsorption of water and minerals.

Epidermis - outer layer of root. Cortex - region between epidermis and vascular cylinder. Pericycle - origin for secondary roots. Xylem - carry water and minerals throughout the plants. Phloem – carry dissolved sugar and organic components

through the plants

Principle: The root culture is initiated from aseptically germinated seeds,

which is maintained in an moving liquid medium, which induce the growth of roots system as in the natural condition.

Also the clone of the excised roots can be established from single root culture by repeatedly cutting and transferring the main root tips or of lateral tips into fresh medium in very subculture at the interval of definite period .

The growth of exercised roots can be expressed in terms of fresh and dry weight, increase in length of main axis, number of emergent laterals and total length of laterals per culture.

Protocol: Initiation of isolated root cultures:

Seeds are first surface sterilized by proper method

Seeds are germinated on whites basal medium at 25⁰C in dark

As the seedlings roots are 20 to 40 mm in length, 10 mm apical tip are exercised and transferred into the liquid medium.

Initiation of clones:

The root culture is established and maintained for 10 days.

Then the main axis of the root is cut into number of pieces, each bearing four or five young laterals.

Then each individual sector inoculum is transferred into medium and incubated.

Again after some maintaince, the growing sector is cut into 4 to 5 sectors to initiate the sector culture again.

Figure: Procedure for root culture

Importance of root culture:1. Give the knowledge of carbohydrate metabolism and role of

minerals, ions and vitamins etc in root growth.2. Provided the basic information regarding the dependence of

roots on shoots for growth hormones.3. Root clones are used in study of effect of various compounds on

root growth.4. Study of nodulation of leguminous roots in culture.5. For regeneration of shoots on roots.6. Study of synthesis of secondary metabolites from root culture.

Ref: Plant tissue culture by Kalyan Kumar De.

Thank you.