Papers

CHAPTER TWO: LITERATURE REVIEW

2.1. Orchid

Orchids are the perennial epiphytic or terrestrial or saprophytic herbs. They come in an infinite variety of colors, shapes and sizes and many make great indoor house plants (Royer, 2003). They range a size from a 2 inch. plant that can sit in the palm of one’s hand to 5 feet giants that need a tub to grow in (Anonymous, 2003). Orchidaceae (Orchid family) is the largest family of the flowering plants. Its name has been derived from the word “Orchis” which means testicles (Royer, 2003). There are more than 48,000 species of orchids in the world. Scientists are always trying to invent new hybrids of orchids and about 800 new species are being added each year (Anonymous, 2005). Orchids are mainly of 2 types:

(a) Terrestrial orchids: they grow on the ground, usually in marshland. Paphiopedilums and Cymbidiums are terrestrial orchids.

(b) Epiphytic orchids: they grow mainly on rocks and trees, where they hold on with thin or thick roots and take in nutrients that fall to them as well as absorb sunlight that reaches to them.

There is one another type of orchid which is few in number. They do not have any green leaves and live on decayed vegetation. These are called saprophytes.

2.2. Different types of orchids in Bangladesh

After research, it has been proved that following orchids are more favorable for the environment of Bangladesh-

1. Indigenous orchid

· Rhyncostylis (fox tail orchid)

· Pierardi sp.

· Arides sp.

· Dendrobium chrysanthum

· Cymbidium sp.

· Arnada sp.

2.2.1. Information about some indigenous orchids

Rhyncostylis:

It is called “Fox tail” or “Draupadi mala”. Its flower stick is about 12-15 inch. A plant may give 5-6 sticks in a flowering season. It blooms in March- April.

Its flower may be white, pink, red, orange, yellow and violet.

It is found in the forests of Sylhet, Chittagong, Mymensingh and Dinajpur.

Pierardi:

It is available in Sylhet, Chittagong and almost everywhere of the country on large rain-trees and different old trees.

Its leaves are thin and stems are long. It blooms in the spring with pink or light pink flowers.

Arides:

It is found in Sylhet and Chittagong on large trees growing naturally. It blooms May- June. It prefers more water and fertilizer but don’t like any movement.

Cymbidium:

Its flowers are beautiful with various colors and shades. Its leaves are also very nice. It remains fresh 2-3 months on plants and about 1 month in flower-vase. SO, it is better as cut-flowers. This genus has 45 sp.

Cymbidium devonianum is available in a large number in Sylhet and Chittagong.

Arnada:

It is known as “Bamboo orchid”. It is available in the forests in a large quantity. It needs not

much care when it is cultivated. Its flower is of pink or light pink. It remains fresh more

than 1 month .The plant may be 8 feet long. It blooms March-April to August.

2. Exotic orchid

· Dendrobium (Thai orchid)

· Oncidium ( dancing doll or lady)

· Phalaenopsis ( moth orchid)

· Cattleya sp.

· Vanda sp.

· Ascocenda sp.

· Brassavola sp.

· Mokara sp.

· Paphiopedilum sp.

2.2.2. Information about some exotic orchids

Dendrobium:

The weather of Bangladesh is favorable for this orchid. If it is maintained properly, it can bloom all the year round. Its flower stays on plants 3-4 months.

It has 1600 sp. in the world! There are some sp. of Dendrobium that grows naturally in Bangladesh.

When plants become 18-20 months old, they start flowering. Each stick contains 12-14 flowers. Flowers are medium in size and of various colors, like- pink, violet, white, yellow

magenta and mixed colors. This is also known as “Sonia”.

Oncidium:

It is called “Dancing doll” or “Lady”. Thailand uses the design of this flower to produce ornaments. Generally it blooms when it is 18-20 months old. Its each stick contains 25-30 flowers. Flowers are mainly of yellow color. This genus possesses 300 sp.

Phalaenopsis:

Its flowers look like butterflies, so it is called “Moth orchid”. Its leaves and roots are thick as a result it can retain water. It blooms flowers of white, pink, lemon, yellow and of stripes of violet, pink, brown etc. It has about 70 sp.

It starts flowering when plants are of 20-22 months old. Each stick contains 4-6 flowers.

Cattleya:

It is the most famous, costly and beautiful flowers with sweet smell than other orchid flowers. It is mainly of white, yellow, bright violet, red and light pink. Recently light blue

and light green Cattleya has been invented but they are very costly. It blooms when it is 20-22 months old. Its flowers are large in size and looks like china-rose. Each stick possesses 2-3 flowers.

Vanda:

In Bangladesh, 6-7 sp. of Vanda grow naturally of which Vanda terret is better. But some gardens of Bangladesh cultivate exotic Vanda. It is commercially cultivated in Thailand and Singapore. Its flowers may be white, pink, blue, violet, yellow, brown etc. It blooms almost all the year round but more in spring and summer. Its flowers remain fresh about 3 months on plants. This genus possesses 70 sp.

Ascocenda:

It blooms twice in a year and its flowers remain fresh for more than 1 month. It is demandable all over the world as a cut- flower. Its flowers may be red, orange, yellow, white, pink, violet or with stripes of various colors.

Brassavola:

Its leaves are long and pointed and flowers are very nice. The flower is white. It blooms more in summer and rainy season but it may bloom all the year round if it is managed properly and liquid fertilizer is applied. It spreads luscious scent at night, for this reason, it is called “Lady of the night”.

Mokara:

It starts flowering when it is 18-20 months old. Its flowers may be of various colors and with stripes or dots. It requires regular watering and fertilizing to produce flowers.

Paphiopedilum:

It looks like slippers of lady, so it is named as “Lady’s slipper”. Its flowers contain stripes and dots which make them more attractive. Leaves of it are also nice. Flowers remain fresh for about one month on plants. Its flowers may be of green, red, yellow, pink, reddish, blackish etc. There are 60 sp. of “Lady’s slipper” orchids in the world.

There are also some orchids which are found in Bangladesh. These are:

· Arathera sp.

· Bokthara sp.

· Dendrobium ( borana green)

· Eridis sp.

· Miltonia sp.

· Paphiopedilum sp.

· Hoya sp. etc.

2.3. Background and history of orchids

The orchid family is not only the largest but also one of the most diverse plant flowering families in the world. The orchid was one of the first plants to evolve on the earth; it was around in the time of the dinosaur, over 120 million years ago (Anonymous, 2003). Most orchids are naturally from the jungle and orchids are found in every continent except Antarctica. Some countries have some species of orchids as their indigenous species as in Bangladesh, Bhutan, India, America, Australia, New-Zealand and Bangkok (Kabir, 2007).

2.4. Physiological Description of Orchids

Orchids can be easily identified by its leaves, stems and roots, flowers, fruits and seeds. Description about Orchids leaves, stems and roots, flowers, fruits and seeds are given below:

Leaves

Orchids generally have simple leaves with parallel veins. They may be ovate, lanceolate or orbiculate and very variable in size. They are normally alternate on the stem. The structure of the leaves corresponds to the specific habitat of the plant. Species, which grow in sunlight or in site that can be occasionally dry, have thick, leathery leaves. On the contrary, species grows in shade, have long, thin leaves. The leaves of most orchids are perennial and in some orchids they are considered as ornamental (Royer, 2003).

Figure-1: Leaves of an orchid

Stems and roots

All orchids are perennial herbs and lack any permanent woody structure. Terrestrial orchids may be rhizomatous or form tubers. The root caps of terrestrial are smooth and white. Epiphytic orchids have modified aerial roots that can sometimes be a few meters long (Amin et al, 2004)

Figure-2: Orchid roots

Flowers

Orchidaceae are well known for the many structural variations in their flowers. Orchid flowers are beautiful and come in all shapes, sizes and brilliant colors. They have two whorls of sterile elements. The outer whorl has three sepals and the inner whorl has three petals (Royer, 2003).

Figure-3: Orchid flower

Pollination

One of the ways in which the orchid is so diverse is its ability to reproduce. Some orchids rely on flying insects, others rely on crawling insects and finally there are orchids that rely on the wind for pollination (Sinha, 2004). Pollinators are often visually attracted by the shape and color of orchid flowers. The flowers may also produce attractive odor. On the other hand, some orchids mainly or totally rely on self-pollination, especially in colder regions where pollinators are particularly rare (Sinha, 2004). After pollination, the sepals and petals fade and wilt but they usually remain attached to the ovary (Sinha, 2004).

Fruits and seeds

The ovary typically develops into a capsule. The ripening of a capsule can take 2 to 18 months. The seeds are generally almost microscopic and very numerous, in some species over a million per capsule. After ripening they blow off like dust particles or spores (Alam, 2002).

2.5. Orchid cultivation process

The cultivation process or techniques can be discussed under following headings-

a. Required materials:

1. Pot

2. Well burnt coal of wood

3. Broken part of tub

4. Burnt bricks

5. Broken bricks

6. Small parts of wood

7. Pebble stone

8. Coir

9. Spray

10. Thin wire to hang etc. (Kabir, 2007)

Figure-4: Coir

In Bangladesh, coal of wood, burnt brick and coir are best for orchid plantation.

b. Types of pots:

* Earthen pots- these are light in weight and contain pores at bottom and sides of the pots. In these pots plants remain cool.

Figure-5: Earthen pots

* Plastic pots- they contain pores at the bottom and sides of pots. These pots are very light in weight.

Figure-6: Plastic pots

*Wooden or bamboo baskets- they are not heavy; air and water can move through these easily. But they may be damaged early because of regular watering.

Figure-7: Basket made of wood and bamboo

*Thumb nails pots- they are best for small plants that are produced through tissue culture.

Figure-8: Thumb nails pots

c. How to plant

1. Orchid plants should be bought which are looking fresh and obviously of good quality.

2. Then pots should be bought according to the size of the plants.

3. Orchid plants should be set in the porous pots and coir, coal of wood, burnt bricks and broken bricks should be put around the base of the plants. It should be done in such a way that the plants can’t move but air can blow.

4. Pots should be hung about 6 feet high through thin wire.

5. All orchid pots should be labeled indicating their names, origin, color of flowers etc.

6. Shade is must for orchid plants which may be made of net or thin fence of bamboos.

7. Orchid should be planted in such places where air can blow from east to west.

8. Orchids require sunlight, otherwise they can’t produce flower but not direct sunlight. They prefer dappled shade.

9. Under the pots of orchids, fern can be planted or reservoir can be established to maintain required humidity artificially.

10. In sunny days, water should be sprayed 2-3 times on leaves and bases of the plants but never on flowers.

11. Cultivator should be careful that orchids are not being over-watered and are not making a water-logged condition.

2-3 times liquid fertilizer should be applied per month for better growth. Pesticides should be sprayed after every 2-3 months to protect pests. (Kabir, 2007)

d. How to care:

· Orchids should not be kept under direct sunlight.

· Which type of orchid is favorable for cultivator’s surrounding environment that should be planted.

· They should not be kept under air conditioned room.

· Orchids should not be moved from their position while they are bearing flower-buds. Because flower-buds don’t like any movement. After completion of flowering, they can be moved.

· Fertilizer and water should never be sprayed on flower-buds or flowers

· Water should never be applied at night, because it is the main cause of fungal attack in orchids.

· Water should not be stayed around the roots; it should be drained out. (Kabir, 2007).

2.6. Orchid preferences

Orchid care is much more an art than a science. Orchids are very easy to care if one takes notice of each orchid’s preferences which include:

Air movement

The more air movement there is, the happier and healthier the orchids will be. Orchids should be placed such places where the foliage actually rustles gently in the breeze. Air movement helps to keep leaves cool (reducing the chance of leaf burn) and also reduces the incidence of bacterial and fungal attack (Anonymous, 2003).

Watering

Orchids require 2 times watering in summer and once in winter per day. They prefer rain water. Their roots which are thinner like thread require more water. On the other hand, whose leaves and roots are thick requires less amount of water. In winter, plats should be watered in such a way that they become dry before the evening. Otherwise, orchids may be attacked by fungal or bacterial disease (Razzak, 2000)

Light

Orchids should not be placed directly into bright sun-light; otherwise there would be a risk of burning leaves. They require light for about 6 hours. They prefer dappled shade. It can be provided by net or bamboo fence. On the other hand, if orchids don’t get 50-60% light, they won’t give flower (Amin, 2004).

Figure-9: (a) Shade in Wonderland Toys garden in Gazipur by net (b) Shade in BRAC orchid garden in Gazipur by net

Pesticide

In Bangladesh, orchids are rarely attacked by fungus, bacteria, virus, ant, spider or other pests. To protect orchids against these following preventive measures should be taken-

· Plants should be watered in such a way that water won’t stay in tub or basket and will dry before evening.

· To maintain ecological balance or to protect environmental pollution, detergent powder can be used instead of pesticides. It will repel spider and ants.

If orchids are attacked, then injured leaves should be cut down or the plant should be burnt. Now-a-days some pesticides are also available nurseries and shops. These are-

1. Redomil

2. Dithane-M 46

3. Macupray

4. Cupravit

5. Bavistin

Procedures of application, required quantity and others necessary information are labeled on the pack.

Humidity

Orchids prefer 50-70% humidity for their growth. This is best achieved by applying humidity tray or a tray filling with rocks and water underneath and near the orchid plants. To maintain required humidity, orchids may be planted near water sources. A cheap but effective way of introducing humidity is by hand- sprayer. (Anonymous, 2005)

Figure-10: Humidity tray

Temperature

18-28°c temperature is optimum temperature for orchid plants (Razzak, 2000).

Fertilizing

To develop the growth of orchid plants, following liquid fertilizers should be applied-

· Miracle grow

10-10-10

· Flowering food

19-31-17

· Plant food

10-15-10

· Micro nutrients

Micro nutrients should be applied as 0.2% concentration in summer (2gm in 1 liter of water) and 0.1% concentration in winter (1gm in 1 liter of water). It should be provided once in a week after watering (Razzak, 2000). For growth of small orchid plant, the liquid fertilizer (Miracle grow 10-10-10) made of Nitrogen, Phosphorus and Potassium (NPK) should be applied as certain amount (Kabir, 2007). For medium sized orchid plants, “Growing orchid food” and “Flowering food” should be applied once by turns in a month (Kabir, 2007). To bloom large flowers, liquid fertilizer “Flowering food” should be sprayed 2-3 times per month (Kabir, 2007). Fertilizers never should be applied on flowers; these should be sprayed only on leaves and roots (Chakraborti, 1986).

A mixture of Urea and water (Urea : Water = 100gm : 15 L) can also be sprayed once per week (Manik, 2009).

Re-potting

Orchids may need re-potting for a number of reasons: the materials in which they grow may be old and it may begin to decompose or it may have been over watered and therefore become water-logged (Anonymous, 2003). Ideally re-potting should happen in January or before the rainy season. But if orchid requires re-potting, the period of the year shouldn’t prevent the cultivator from doing so. Orchids should be re-potted for every 1-2 years. After re-potting, the plants should be kept in a shady place for 1-2 weeks. Then they must be labeled indicating the name, color, origin etc. of orchids (Iqbal, 2009).

Table: 1.Species wise requirements

Phalaenopsis		Dendrobium	Oncidium	Cymbidium	Cattleya
Light	Bright light, never direct sun-light.70-85% shade.	Strong indirect light. 25-50% shade while growing and 50-75% while plant is resting.	Bright indirect sun. 20-60% shade.	Bright indirect sun. 25-50% shade.	Strong but not direct sun. 50-70% shade.
Temp.	70-90 F. days 60-65F. nights.	65-95F. days 45-60F. nights.	85F.days 60 F. nights.	70-85F. days 55 F. nights.	70-85 F. days 55-60 F. nights.
Water	Do not let dry out. Drainage is important.	Water more often during the growing cycle. Water less when plants are resting (winter).	Frequent when active. Less during winter months.	Keep moist in summer. Somewhat dry between watering in winter.	Allow to dry between watering.
Food	Fertilize at least twice per month.	Fertilize at least twice per month.	Fertilize at least twice per month.	Fertilize at least twice per month.	Fertilize at least twice per month.

Source: Kabir, 2007, Orchid.

2.7. Orchid society in Bangladesh

All countries of the world growing orchid must have an orchid society to share information with others. To make the orchids well-known to all, a society was also established on 2^nd October, 1989 at Dhaka in Bangladesh by the assistance of National Museum of Science and Technology, named “Orchid Society of Bangladesh”. Nasim Iqbal Ali is its president.

Activities of this society

1. It arranges an orchid show every year at September to make orchids familiar and popular.

2. It informs about how to plant and how to take care of orchids.

3. It solves the problems that are facing orchid cultivators.

4. It tries to improve the qualities of orchids through various experiments and researches and through invention of new hybrids.

5. It deals with how orchids can be exported from Bangladesh.

2.8. Use of orchids

1. One orchid genus, Vanilla, is commercially important. Because its essence is used as foodstuff flavoring in coca-cola, ice-cream, cake etc.

2. The scent of orchids is analyzed by perfumists to identify potential fragrance chemicals.

3. In the Indian sub-continent, orchids are being used from ancient period to produce medicine for herbal treatment. (Ming, 2003).

4. Bangkok makes ornaments using the design of orchid flower.

5. Candle is also made using the design of orchid flowers.

6. Essence of orchid is used in soap manufacturing, like, Lux (orchid touch).

7. The other important use of orchids is their cultivation for the enjoyment of flowers. Orchidaceae family provides a large number of orchid flowers of various colors, shapes, sizes with luscious scent. Singapore, Bangkok, Japan, Malaysia is earning a lot of foreign currency by exporting orchids. Buyers now bid hundreds of dollars on new hybrids or improved ones, as orchids are being one of the most popular cut-flowers of the world market.