Biology

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Modes Of Reproduction

All modes of reproduction have some basic features such as synthesis of RNA and proteins, replication of DNA, cell division and growth, formation of reproductive units and their fertilization to form new individuals.

Organisms exhibit two major modes of reproduction namely asexual and sexual reproduction. Reproduction by a single parent without the involvement of gamete formation is asexual reproduction and the offspring produced are genetically identical.

Asexual reproduction is usually by amitotic or mitotic division of the somatic (body) cells, hence is also known as somatogenic or blastogenic reproduction.

When two parents participate in the reproductive process involving two types of gametes (ova and sperm), it is called sexual reproduction.

Binary fission:
Single parent cell doubles its DNA, then divides into two cells.

Budding:
Small growth on surface of parent breaks off, resulting in the formation of two individuals.

Fragmentation:
Organisms break into two or more fragments that develop into a new individual.

Asexual and sexual reproduction, two methods of reproduction among animals, produce offspring that are clones or genetically unique. Sexual reproduction is a better mode of reproduction as compared to asexual reproduction because it involves meiosis and the fusion of male and female gametes.

Such a fusion involving two parents results in offspring which are not identical to the parents. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism.

Asexual reproduction is not limited to single-celled organisms. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. Reproduction is the process by which new individuals are produced by the parents. The process of reproduction ensures that a plant or animal species does not disappear from Earth. This process is very important in maintaining stability in the ecosystem and for the continuation of life on earth.

Learninsta presents the core concepts of Biology with high-quality research papers and topical review articles.

Entrepreneurial Botany

Entrepreneurial Botany is the study of how new businesses are created using plant resources as well as the actual process of starting a new business. An entrepreneur is someone who has an idea and who works to create a product or service that people will buy, by building an organization to support the sales. Entrepreneurship is now a popular topic for higher secondary students, with a focus on developing ideas to create new ventures among the young people.

Vast opportunities are there for the students of Botany. In the present scenario students should acquire ability to merge skills and knowledge in a meaningful way. Converting botanical knowledge into a business idea that can be put into practice for earning a livelihood is the much-needed training for the students.

Few examples for activities of entrepreneurship are Mushroom cultivation, Single cell protein (SCP) production, Seaweed liquid fertilizer, Organic farming, Terrarium, Bonsai and Cultivation of medicinal and aromatic plants. This part of the chapter is dealt about organic farming in brief.

Organic farming

Organic farming is an alternative agricultural system in which plants/crops are cultivated in natural ways by using biological inputs to maintain soil fertility and ecological balance thereby minimizing pollution and wastage. Indians were organic farmers by default until the green revolution came into practice.

Use of biofertilizers is one of the important components of integrated organic farm management, as they are cost effective and renewable source of plant nutrients to supplement the chemical fertilizers for sustainable agriculture. Several microorganisms and their association with crop plants are being exploited in the production of biofertilizers. Organic farming is thus considered as the movement directed towards the philosophy of Back to Nature.

I. Organic Pesticide

Pest like aphids, spider and mites can cause serious damage to flowers, fruits, and vegetables. These creatures attack the garden in swarms, and drain the life of the crop and often invite disease in the process. Many chemical pesticides prove unsafe for human and the environment. It turns fruits and vegetables unsafe for consumption. Thankfully, there are many homemade, organic options to turn to war against pests.

II. Bio-pest repellent

Botanical pest repellent and insecticide made with the dried leaves of Azadirachta indica

Preparation of Bio-pest repellent

• Pluck leaves from the neem tree and chop the leaves fiely.
• The chopped up leaves were put in a 50-liter container and fill to half with water; put the lid on and leave it for 3 days to brew.
• Using another container, strain the mixture which has brewed for 3 days to remove the leaves, through fie mesh sieve. The fitrate can be sprayed on the plants to repel pests.
• To make sure that the pest repellent sticks to the plants, add 100 ml of cooking oil and the same amount of soap water. (The role of the soap water is to break down the oil, and the role of the oil is to make it stick to the leaves).
• The stewed leaves from the mixture can be used in the compost heap or around the base of the plants.

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An Overview Of Medicinal Plants

India is a treasure house of medicinal plants. They are linked to local heritage as well as to global-trade. All institutional systems in India primarily use medicinal plants as drug sources. At present, 90% collection of medicinal plants is from the non-cultivated sources.

Growing demand for herbal products has led to quantum jump in volume of plant materials traded within and across the countries. Increasing demand exerts a heavy strain on the existing resources. Now efforts are being made to introduce cultivation techniques of medicinal plants to the farmers.

Medicinal plants play a significant role in providing primary health care services to rural and tribal people. They serve as therapeutic agents as well as important raw materials for the manufacture of traditional and modern medicines.

Medicinally useful molecules obtained from plants that are marketed as drugs are called Biomedicines. Medicinal plants which are marketed as powders or in other modified forms are known as Botanical medicines.

Keezhanelli

Botanical name: Phyllanthus amarus
Family: Euphorbiaceae (Now in Phyllanthaceae)

Origin and Area of cultivation:

The plant is a native of Tropical American region and is naturalised in India and other tropical countries. It is not cultivated and is collected from moist places in plains. Phyllanthus maderspatensis is also commonly sold in the medicinal plant markets collected from non-forest are as keezhanelli.

Active principle:

Phyllanthin is the major chemical component.

Medicinal importance

Phyllanthus is a well-known hepato-protective plant generally used in Tamil Nadu for the treatment of Jaundice. Research carried out by Dr. S P Thagarajan and his team from University of Madras has scientifially proved that the extract of P. amarus is effective against hepatitis B virus.

Nilavembu

Botanical name: Andrographis paniculata
Family: Acanthaceae

Andrographis paniculata, known as the King of Bitters is traditionally used in Indian systems of medicines.

Active principle:

Andrographolides.

Medicinal importance:

Andrographis is a potent hepatoprotective and is widely used to treat liver disorders. Concoction of Andrographis paniculata and eight other herbs (Nilavembu Kudineer) is effectively used to treat malaria and dengue.

Psychoactive Drugs

In the above chapter you have learnt about plants that are used medicinally to treat various diseases. Phytochemicals / drugs from some of the plants alter an individual’s perceptions of mind by producing hallucination are known as psychoactive drugs. These drugs are used in all ancient culture especially by Shamans and by traditional healers. Here we focus on two such plants namely Poppy and Marijuana.

Opium poppy

Botanical name: Papaver somniferum
Family: Papaveraceae

Origin and Area of cultivation:

Opium poppy is native to South Eastern Europe and Western Asia. Madhya Pradesh, Rajasthan and Uttar Pradesh are the licenced states to cultivate opium poppy.

Opium is derived from the exudates of fruits of poppy plants. It was traditionally used to induce sleep and for relieving pain. Opium yields Morphine, a strong analgesic which is used in surgery. However, opium is an addiction forming drug.

Cannabis / Marijuana

Botanical name: Cannabis sativa
Family: Cannabiaceae

Origin and Area of Cultivation:

Marijuana is native to China. States such as Gujarat, Himachal Pradesh, Uttarkand, Uttarpradesh and Madhaya Pradesh have legally permitted to cultivate industrial hemp/Marijuana. The active principle in Marijuana is trans-tetrahydrocanabinal (THC). It possess a number of medicinal properties. It is an effective pain reliever and reduces hypertension.

THC is used in treating Glaucoma a condition in which pressure develops in the eyes. THC is also used in reducing nausea of cancer patients undergoing radiation and chemotherapy. THC provides relief to bronchial disorders, especially asthma as it dilates bronchial vessels.

Because of these medicinal properties, cultivation of cannabis is legalized in some countries. However, prolonged use causes addiction and has an effect on individual’s health and society. Hence most of the countries have banned its cultivation and use.

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Traditional System Of Medicines

India has a rich medicinal heritage. A number of Traditional Systems of Medicine (TSM) are practiced in India some of which come from outside India. TSM in India can be broadly classified into institutionalized or documented and non-institutionalized or oral traditions. Institutionalized Indian systems include Siddha and Ayurveda which are practiced for about two thousand years.

These systems have prescribed texts in which the symptoms, disease diagnosis, drugs to cure, preparation of drugs, dosage and diet regimes, daily and seasonal regimens. Non – institutional systems, whereas, do not have such records and or practiced by rural and tribal peoples across India. The knowledge is mostly held in oral form. The TSM focus on healthy lifestyle and healthy diet for maintaining good health and disease reversal.

Siddha system of medicine

Siddha is the most popular, widely practiced and culturally accepted system in Tamil Nadu. It is based on the texts written by 18 Siddhars. There are different opinions on the constitution of 18 Siddhars. The Siddhars are not only from Tamil Nadu, but have also come from other countries. The entire knowledge is documented in the form of poems in Tamil.

Siddha is principally based on the Pancabuta philosophy. According to this system three humors namely Vatam, Pittam and Kapam that are responsible for the health of human beings and any disturbance in the equilibrium of these humors result in ill health. The drug sources of Siddha include plants, animal parts, marine products and minerals.

This system specializes in using minerals for preparing drugs with the long shelf-life. This system uses about 800 herbs as source of drugs. Great stress is laid on disease prevention, health promotion, rejuvenation and cure.

Ayurveda system of medicine Ayurveda supposed to have originated from Brahma. The core knowledge is documented by Charaka, Sushruta and Vagbhata in compendiums written by them. This system is also based on three humour principles namely, Vatha, Pitha and Kapha which would exist in equilibrium for a healthy living. This system Uses more of herbs and few animal parts as drug sources. Plant sources include a good proportion of Himalayan plants. The Ayurvedic Pharmacopoeia of India lists about 500 plants used as source of drugs.

Folk system of medicine

Folk systems survive as an oral tradition among innumerable rural and tribal communities of India. A consolidated study to document the plants used by ethnic communities was launched by the Ministry of Environment and Forests, Government of India in the form of All India Coordinated Research Project on Ethnobiology. As a result about 8000 plant species have been documented which are used for medicinal purposes. The efforts to document in several under-explored and unexplored pockets of India still continue.

Major tribal communities in Tamil Nadu who are known for their medicinal knowledge include Irulas, Malayalis, Kurumbas, Paliyans and Kaanis. Some of the important medicinal plants are discussed below.

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Cosmetics | Aloe | Perfumes | Jasmine and Its Uses

Traditionally in Southern India, people have been using turmeric, green gram powder, henna, sigaikai and usilai for their skin and hair care. These were mostly home prepared products that are used for grooming. Today, cosmetics have a high commercial value and have become chemical based industrial products. Providing personal care services has become a major industry.

In recent years, people have realized the hazards of chemicalbased cosmetics and are turning back to natural products. In this chapter one of the major plants namely Aloe which is used in the cosmetic industries is discussed.

Aloe

Botanical name: Aloe vera
Family: Asphodelaceae (formerly Liliaceae)

Origin and Area of cultivation:

It is a native of Sudan. It is cultivated on a large scale in Rajasthan, Gujarat, Maharashtra, Andhra Pradesh and Tamil Nadu.

Uses

‘Aloin’ (a mixture of glucosides) and its gel are used as skin tonic. It has a cooling effect and moisturizing characteristics and hence used in preparation of creams, lotions, shampoos, shaving creams, after shave lotions and allied products.

It is used in gerontological applications for rejuvenation of aging skin. Products prepared from aloe leaves have multiple properties such as emollient, antibacterial, antioxidant, antifungal and antiseptic. Aloe vera gel is used in skin care cosmetics.

Perfumes

The word perfume is derived from the Latin word Per (through) and fumus (to smoke), meaning through smoke. It refers to the age-old tradition of burning scented woods at religious ceremonies.

In early days, when people were less conscious of personal hygiene, essential oils not only masked offensive odours, but also may have acted as antiseptics. Perfumes are added to baths and used for anointing the body.

Perfumes are manufactured from essential oil which are volatile and aromatic. Essential oils are found at different parts of the plant such as leaves, (curry leaf, mint), flowers (rose, jasmine), fruits (citrus, straw berry) and wood (sandal, eucalyptus).

Jasmine

Botanical name: Jasminum grandiflrum
Family: Oleaceae

Jasmine, as a floral perfume, ranks next to the rose oil. Major species cultivated on the commercial scale is Jasminum grandiflorum, a native of the north-western Himalayas. In Tamil Nadu, the major jasmine cultivation centres are Madurai and Thvalai of Kanyakumari District.

The essential oil is present in the epidermal cells of the inner and outer surfaces of both the sepals and petals. One ton of Jasmine blossom yields about 2.5 to 3 kg of essential oil, comprising 0.25 to 3% of the weight of the fresh flower.

Uses

Jasmine flowers have been used since ancient times in India for worship, ceremonial purposes, incense and fumigants, as well as for making perfumed hair oils, cosmetics and soaps. Jasmine oil is an essential oil that is valued for its soothing, relaxing, antidepressant qualities.

Jasmine blends well with other perfumes. It is much used in modern perfumery and cosmetics and has become popular in air freshners, anti-perspirants, talcum powders, shampoos and deodorants.