Papaya: Classification, Distribution, Botanical Description, and Uses
Introduction
The fruit of the papaya plant, Carica papaya, popularly known as papaw or pawpaw, is the sole member of the plant family Caricaceae with chromosome number 18. (Martelleto et al 2008). The red- and pink-fleshed varieties of the Carica papaya are referred to as papaya in Australia, whereas the yellow-fleshed varieties are called pawpaw. The plant is known as papaya in India (Dhillon 2013). It is indigenous to America’s tropics. One of the most significant economic crops in the tropics and subtropics is papaya (Reddy and Gowda 2014). Despite being a tropical fruit, it may also be cultivated in sub-tropical environments (Allan 2002, Galan and Rodriguez 2007). A fruit crop with a brief lifespan that can reach a height of 30 feet is the papaya. The stem is hollow and typically unbranched with softwood. Long stalked, palm-like leaves are present. Fruit from a pistillate flower has an ovoid-oblong form. The fruit is a berry with flesh. Smooth and green when unripe, papaya skin turns yellowish or orange when fully ripe. Orange or reddish-orange, the centre cavity is five-angled. The seeds are round, wrinkled, and black or greyish. The gelatinous sarcotesta is made of the exterior integument (Kumar et al 2013). Although papayas are hermaphrodite, they can also be dioecious. It is a well-liked crop among farmers, and there is a steady market demand for the fruits. It is a highly lucrative crop that has a favourable cost-benefit ratio (Sharma and Zote 2010). Papaya growth stops in subtropical climates at temperatures below 11 °C (Allan et al 2002). Therefore, papaya growing under protection in a subtropical area might offer the best conditions for the fruit’s development and productivity. With the important additional benefit of the Ring spot virus being excluded, growth and blooming benefits from the environment within the enclosed chambers result in improved yields, both in fruit quality and quantity (Galan and Rodriguez 2007). Determining papaya productivity and quality characteristics under protected agriculture is therefore crucial.
Classification
Kingdom: Plantae
Order: Brassicales
Family: Caricaceae
Genus: Carica
Botanical name: Carica papaya Linn.
Common Name: Papaya, Paw Paw, Kates, Papaw
Part Used: Leaves, Fruits, bark, leaves
Distribution
The papaya originated in Tropical America and was brought to India in the eighteenth century. Currently, there is a lot of papaya being grown in Australia, Hawaii, India, Sri Lanka, Malaya, Myanmar, South Africa, and Kenya. Almost all tropical and subtropical nations in the world currently grow it. It is mostly grown in India’s Bihar, Assam, Maharashtra, Madhya Pradesh, and Andhra Pradesh states.
Botanical Description
1. Carica papaya is a typically unbranched, 2–10 m tall, tufted tree that resembles a large herb. Commercial growers frequently remove plants when they reach a height where the fruits are difficult to harvest.
2. Near the end of the straight stem, large, palmately lobed leaves with long, strong leaf stalks (up to 125 cm) are thickly connected (alternating more or less spirally), spreading to form a loose open crown.
3. According to Campostrini and Yamanishi (2001a), the leaf stalks (petioles) terminate in leaf blades that are 20–60 cm (to 75–100 cm) across, each of which has five or seven pinnately cut lobes.
4. Large leaf scars are prominently patterned on the trunk, which tapers from a base width of 10-30 cm to a crown width of 5-7.5 cm as it ages. The bark is thin and frequently hollow (between nodes) (Elias, 1980).
5. Phloem makes up the majority of the soft, pulpy wood, with only a little amount of secondary xylem (Whitmore, 1978; Carlquist, 1998).
6. This plant grows quickly and has 15 to 30 mature leaves, each of which lasts 2.5 to 8 months. It also produces 1.5 to nearly 4 new leaves per week (Sippel et al., 1989; Allan et al., 1997; Mabberley, 1998; Nakasone and Paull, 1998; Fournier et al., 2003).
7. The position of the leaf inside the plant’s canopy (i.e., self-shading) appears to be a factor in leaf senescence rather than only the leaf’s age (Ackerly, 1999).
8. The unripe fruits as well as all other plant parts contain a thin, bitter latex. Feral trees have a 15–20 year lifespan (Anon, 2003). When older or wounded, plants can acquire a forked trunk or a few branches; in some regions (like Kenya), farmers can induce numerous trunks by pinching seedlings or trimming back established plants (Dodson and Gentry, 1978; Rao, 1993; Malo and Campbell, 1994).
9. Depending on the sex of the tree, inflorescences, and flowers have different morphologies.
10. Typically, varieties are polygamous or dioecious (having unisexual blooms and only male and female plants) (with bisexual and unisexual flowers and hermaphrodite and single-sex plants).
11. One or more enormous bell-shaped blooms with curved distinct petals are present on the stalk (peduncle) of female plants, which is only 2.5–6 cm long.
12. On male plants, trumpet-shaped flowers with several, much smaller petals (and stamen filaments) united in a long, narrow tube with flared lobes grow on hanging, branching stalks (called panicles) that range in length from 60 to 100 cm (to over 150 cm) (Fisher, 1980; Calif. Rare Fruit Growers, 1997; Nakasone and Paull, 1998; Ronse Decraene and Smets, 1999).
12. These formations on hermaphrodite plants are midway between the unisexual and bisexual flower types, with shorter, tubular, lower constricted, and bigger petal lobes bisexual flowers on stalks under 25 cm long.
13. Sometimes, male flowers are also produced by hermaphrodite plants (Crop Knowl. Master, 1993). On short stalks, some plants develop male blooms.
Soil and climate
It grows in a variety of soil types, but loams with a consistent texture up to 1.8 metres deep show the highest performance. The soil must have sufficient drainage, which is the most crucial condition. Due to the development of the collar-rot disease, even two to three cm of stagnant water around the tree for a few hours is likely to cause damage. Papaya thrives in tropical areas with summertime temperatures between 35°C and 38°C. The quality of the fruit is typically worse at higher altitudes. Its inability to withstand extremely hot summers or frost hinders its ability to be grown in Northern India. Sometimes, male flowers are also produced by hermaphrodite plants (Crop Knowl. Master, 1993). On short stalks, some plants develop male blooms. A dry, mild climate tends to make the fruits more delicious, but they cannot endure frost or extremely hot summers. Windbreaks must be installed in regions where strong winds frequently occur to protect the trees from wind damage. The temperate temperatures and lack of mosaic and leaf curl virus illnesses make Tamil Nadu a suitable place to cultivate papaya. These characteristics support papaya cultivation all year long.
Propagation
Papayas are most frequently reproduced from seeds. Seeds are harvested from huge, ripe, mature fruits that are either female or hermaphrodite-borne, depending on the situation. The fruits are split open, and trays are used to delicately remove the seeds. They are cleaned, dried in the sun or the shade, and then put into bottles for storage. Fine cold wood ash can be combined with fresh seeds to assist keep the seeds separate while drying by absorbing the sticky coating on them. To raise a crop in a hectare, you need about 500 g of seed. Although seedlings can be raised in polythene bags or raised on raised nursery beds, the latter method produces better seedlings. Each polybag should contain two seeds of the gynodioecious type or five to six seeds of the dioecious type. Cuttings and grafts can also be used to multiply papaya plants. However, as vegetative methods of propagation are not cost-effective, seed-based propagation is favoured.
Chemical Composition
Saponins, alkaloids, tannins, flavonoids, cardiac glycosides, anthraquinones, phlobatinins, anthocyanosides, and phenols were all found in the C. papaya according to the phytochemical investigation (Imaga, et al., 2010). The extraction solvent utilized affects the presence and composition of these diverse phytochemicals, which vary from one plant section to the next (Doughari, et al., 2009, Imaga et al., 2010). According to Kumar, et al. (2013), papaya is a nutritious fruit with moderate amounts of protein and the same amounts of minerals, namely iron, calcium, and phosphorus, as well as vitamin A and C, as well as a high concentration of the enzyme papain.
Uses
1. The entire Carica papaya has a special medical application. Carica papayas can be used in all parts of the body to treat illness. Papaya Carica is divided into latex, peel, roots, fruit, and seeds.
2. Papaya leaf has a wide range of advantages. Many deadly diseases are treatable with it. Papaya leaves are sometimes cooked and eaten like spinach in various regions of Asia.
3. Dengue Fever
White blood cell and platelet counts are increased by the juice from the Carica papaya leaves. Clotting is also normalized, and the liver is repaired. When a patient with dengue fever received an extract of papaya juice, their platelet and white blood cell counts returned to normal within 24 hours. This plant’s secondary metabolite is a huge repository of compounds. The aqueous extract shows potential anti-dengue fever action.
4. Stopping the Growth of Cancer Cells
Cancer cell proliferation is inhibited by Carica papaya leaf extract. It increases the production of vital signaling molecules known as Th1-type cytokines, which are essential for controlling the immune system. Added advantages of papaya leaves include:
1. It can treat acne. 2. It helps to reduce menstruation pain and improves appetite in patients with reduced appetite. 3. It can help in easing nausea.
5. Fruits
The fruit papaya is a fantastic source of vitamins, minerals, and dietary fibre. Papaya contains the phytoalexin danielone. This substance exhibits strong anti-fungal activity.
Uses for the fruit include
Fresh, ripe papaya should be consumed every morning to prevent indigestion and constipation, and it also helps to boost appetite. It also acts as a remedy for indigestion and helps to prevent heart attack and stroke. Carica papaya fruit can be used to treat toothache, gum disease, and mouth ulcers.
6. Seeds
The papaya Carica seed is dark in colour. It tastes quite sour and hot. It can occasionally take the place of black pepper. Compared to other sections of the tree, papaya seeds are more medicinally valuable and have a strong flavour. Antibacterial papaya seeds are excellent at fighting staphylococcus infections. The seeds aid in renal failure prevention and toxin protection for the kidneys. aids in the recovery from typhoid and piles. More nutrients are contained in dried papaya seeds. By pulverising this seed and including it in meals, you can improve digestive issues and add enzymes to your diet.
7. Peel
Papaya peel can be used as a home remedy and is frequently used as a cosmetic. Papaya peel can be used as a muscle relaxant, as well as a sunscreen and soothing agent. It also aids in the fight against dandruff.
8. Roots
In several Asian nations, the liquid from the root is used to treat urinary issues. For the treatment of dyspepsia, papaya roots can be boiled to make a decoction.
Uses for Carica Papaya in Medicine
a) Cancer
Papaya can stop cancer cells from growing. The fruit’s fibre binds to the cancer-causing cell and prevents it from contacting healthy cells. The papaya’s nutrients offer the cells a way that prevents oxidative damage synergistically. Men who consume lycopene-rich fruits, such as guava, papaya, and tomatoes, are less likely to get prostate cancer than those who do not.
b) Anticoagulant Effect
The papain enzyme found in Carica papayas can speed up the clotting of prothrombin. Additionally, it can remove ulcers, burns, and wounds.
c) Wound Healing
Papaya latex was found to aid in the healing of wounds. The wound-affected area permitted the papaya latex to flow. Papain and chymopappain are well known for having excellent wound healing properties. It is well known that papain and chymopappain are particularly good at healing wounds.
d) Preserves lung health
Consuming vitamin A-rich foods can aid to maintain healthy lungs. A person’s life can be saved by consuming foods high in vitamin A since smokers and passive smokers are constantly exposed to smoke.
e) Rheumatoid Arthritis
Humans are protected from inflammatory polyarthritis, a type of rheumatoid arthritis, by foods high in vitamin C.
f) Anti-Inflammatory effect
Carica papaya contains antioxidants and protein enzymes like papain and chymopapain. Asthma and osteoarthritis are two conditions where severe inflammation is reduced by vitamin E and beta carotene.
Humans have used papaya to treat the following conditions:
Amebicide – Japan;
Asthma and respiration – Mauritius, Mexico, and the Philippines;
Abortifacient – Sri Lanka and Turkey; India bactericide
Corns and boils — India, Malaysia, and the Philippines; Cancer — Australia and Mexico;
Fever and dysentery — Mexico; Diarrhea and dysentery — Japan and West Africa; Digestive — China, and Turkey; Dyspepsia — Mexico;
Malaysia hypertension
Indonesia and Malaysia: (increase/stimulate) milk output