Hessami Plant Tissue Culture Laboratory
Hessami Plant Tissue Culture Laboratory, popularly known as HPTCL was found in 1995 by Shahriar Hessami and started in vitro plant tissue propagation as a practical research in a
small tissue culture laboratory .At present HPTCL is active in the field of commercial productions including Banana, Date palm, Potato and Strawberry. Today HPTCL is a large plant
tissue culture laboratory in Iran.
Banana Varieties: Dwarf Cavendish, Valery, Grande Naine, Williams
Date Palm Varieties: Zahidi, Madjool
Potato Varieties: Arka, Atlantic, Desiree, Eden, Heather, Iris, Kennebec, Lori, Palladia, Patrones, Sieglinde, Sissi, Tanja, Triumf, Valetta
Strawberry Varieties: Camarosa, Selva
Agricultural biotechnology is the new way of biological science and it is the most powerful tool for future advancement in the various fields of agriculture. Plant tissue culture is the
technique of growing plant cells, tissues and organs in an artificial prepared nutrient medium, under aseptic conditions. Tissue culture technology is used for the production of new plant
varieties which are difficult to propagate plants, produce secondary metabolites and transgenic plants. However, there are still major opportunities to produce and distribute high quality
planting material, e.g., crops like banana, date palm, potato, ornamentals, fruit and forest trees. The main advantage of tissue culture technology lies in the production of high quality and
uniform planting material that can be multiplied on a year round basis under disease free conditions anywhere irrespective of the season and weather. During the last thirty years, tissue
culture based plant propagation has emerged as one of the leading global agro technologies.
Plant tissue cultures are initiated from tiny pieces, called explants, taken from any part of a plant. In practice, the explant is removed surgically, surface sterilized and placed on a nutrient
medium to initiate the mother culture, that is multiplied repeatedly by subculture. The following plant parts are extensively used in commercial micro propagation.
Shoot tip culture: Shoots develop from a small group of cells known as shoot apical meristem. They give rise to new tissues and organs, and communicate signals to the rest of the plant.
Shoot tips are the most popular source of explants to initiate tissue cultures.
Axillary bud cultures: This consists of a piece of stem with axillary bud culture.
Other sources of explants: In some plants, leaf discs, small pieces of stems, immature zygotic embryos have also been used as explants.
Cell suspension and callus culture: plant parts have been cultured to initiate callus. A callus is a mass of unorganized cells, which is many cases, upon transfer to suitable medium, is
capable giving rise to shoot buds and somatic embryos, which then from complete plants. Such calli on culture in liquid media on shakers are used for initiating cell suspensions.
Pathways of culture cells and tissues
Regeneration and organogenesis: In many cases, the axillary buds formed in the culture undergo repetitive proliferation, and produce larger number of tiny plants. The plants are then
separated from each other and rooted either in the next stages of micro propagation.
Somatic embryogenesis: In this pathway, cells or callus cultures on solid media or in suspension cultures from embryo like structures called somatic embryos, which on germination
produce complete plants. The primary somatic embryos are also capable of producing more embryos through secondary somatic embryogenesis.
Process of micropropagation
The process of plant micro propagation is usually divided into the following stages:
Stage 0 - pre propagation step or selection and pre treatment of suitable plants.
Stage 1 - initiation of explants, surface sterilization, establishment of mother explants.
Stage 2 - subculture for multiplication or proliferation of explants.
Stage 3 - shooting and rooting of the explants.
Stage 4 - acclimatization.
In vitro growth of plants is largely determined by the composition of the culture medium. The main components of most plant tissue culture media are mineral salts and sugar as carbon
source and water. Other components may include organic supplements, growth regulators, and a gelling agent.
The commercial production of micro propagated bananas is now established in many countries. Micro propagation of bananas generally follows the laboratory and nursery stages.
Stage 0 Mother plants selection and primary explants origin
Several buds may be taken from a single mother plant as a source for explants. These will be multiplied to several thousand plants; therefore, the careful selection of the source plant is
extremely important. Special care should be taken to avoid the use of explants taken from plants infected with viruses. It is expected that the future differences among laboratories with
respect to the quality of their product will be determined mainly by their plant material source.
Stage 1 Culture establishment
The outer leaves, leaf bases and corm tissue of a select explant are trimmed to 2*2*4 cm and surface sterilized with hypochlorite. Thereafter, the process continues under aseptic
conditions. The shoot tips are trimmed to approximately 5*5*5 mm and transferred directly to the culture medium. Size is an important factor for successful establishment.
Stage 2 Multiplication
Multiplication of propaguls is obtained by subdividing the newly formed shoots or bud clusters and reculturing them on a fresh medium. Proliferation and multiplication depend on
genotype, culture medium composition, and size of initial explant, its preparation procedure and age of culture.
Stage 3 Preparation of plants for re-establishment in soil
At this stage, steps are taken to induce development of individual plants to such a size that they will be able to survive in soil. Development is induced by sub culturing propagules to a
medium, which reduces auxiliary bud and shoot formation. The optimal hormone concentration of the medium and the cytokinin / auxin ratios have to be adjusted for each clone. Our
experiences indicate that the optimal size of plantlets at the end of this stage is 4 5 cm, with four leaves, and with a well developed root system.
At this stage the aim is to grow the plants to a size which will ensure establishment after planting in the field. There are two steps.
Step 1 Acclimatization to ex vitro conditions
Acclimatization involves significant changes: adaptation from heterotrophic to autotrophic conditions, increase in light intensity and decrease in humidity, and exposure to diurnal
temperature change and to pathogens.
Step 2 Growing to field planting size
It is preferable to establish the final nursery close to the planting area in order to minimize the cost of transporting fully grown plants and to reduce the possibility of damaging them.
Shade houses or green houses are best for this purpose.
Date Palm Micropropagation
Date palm is economically important in tropical and subtropical regions. The rapid propagation of date palm is impossible because the number offshoots produced by each palm tree is
low and cannot be successfully controlled. Tissue culture in palms until thirty years ago, little success was achieved in inducing and maintaining good callus.
Date palm plantlets may be produced through; 1) organogenesis and division of shoot tips and lateral buds 2) asexual embryogenesis, initiation and germination of somatic embryos
Organogenesis techniques based on meristematic tissues potentiality and avoid callus formation. This technique consists of 4 steps; 1) Initiation of meristematic buds 2) Multiplication
3) Elongation 4) rooting.
Somatic embryogenesis is based on the callus production and multiplication, followed by germination and elongation of somatic embryos. Up to now, this technique had shown to be
genotype with a high rate of multiplication and a high survival rate upon transfer to soil.
Several stages have been used to acclimatize date palm plantlets under greenhouse conditions.
1) Plants are then rinsed in water to remove adhering agar.
2) A spray with systematic fungicide solution is necessary that protect the plant from fungal attack.
3) Soil medium must always be sterile and usually consist of peat and vermiculite mixture.
4) The adequate PH to work with should be 6.5.
5) Plastic pots (7 12 cm) are often used for date palm transplanting.
6) Plants are immediately irrigated with suitable nutrient solution before their incubation in a controlled greenhouse.
Plants for a period 4 months stay in the greenhouse and after then, their transfer to a less controlled nursery.
A large number of virus-free potato microplants can be obtained by the micropropagation technique. Different methods of potato micropropagation are used in various laboratories but
in all of them, a very small part of the plant is cultured on a standard nutrient medium under aseptic conditions. Tissue culture can be obtained different types of diseases free materials
such as plantlets and microtubers in large quantities. The quality of the in vitro plantlets and of the microtubers can be affected by a combination of grow regulators, environmental
conditions during culture and in vitro medium.
Plantlets are very small plants produced under completely sterile conditions. In vitro plantlets are planting under non sterile (in vivo) conditions can be produced transplants.
Microtubers are very small tubers produced in vitro conditions with a weight 0.2 0.7 g and 3 10 mm diameter. Generally, microtubers have a long period of dormancy.
Transplants and microtubers produced minituber under in vivo conditions after planting them in a soil or soil-less medium. Minitubers are small tubers of 5 25 mm in diameter and a
range in weight between 0.1 10 g. Minitubers can be planted directly in the field.
Micropropagation of strawberry has been used in horticultural production for more than 25 years and perhaps the first fruit crop in which micropropagation technique was first
standardized. Strawberry is the fruit plant, which requires very high number of plants/ha (50000 -60000) and this is demand can easily be met through micropropagation. Usually, growth
of tissue cultured plants in the field is very good, producing lush green foliage. Generally, these plants are free from diseases, producing high yield of quality fruits. Micropropagation of
strawberry follows the laboratory and nursery stages.
Laboratory stage includes mother plants selection, meristem culture, multiplication and rooting.
Nursery stage includes Acclimatization and growing to field planting size.
Giah Alley, Next to Golchin tea St
Shahrake Naaz, Fardis
Tel: +98261 6805962
Fax: +98261 6802925