Description: A fast growing, woody, tree-like herb that grows up to 3 m tall. It normally does not branch but if the top is cut off or injured, it produces a few branches. Trunk is straight, hallow and green or deep purple in colour with prominent leaf scars. Leaves are arranged spirally and clustered at the top of stem. Leaf stalk is about 1m long, hallow and succulent. Leaf is divided deeply into five to nine segments with prominent yellowish ribs and veins. Flowers are fleshy, waxy and slightly fragrant. Some plants bear only short-stalked female flowers whereas some other plants may bear only male flowers, which are clustered on 1.3 to 1.6 m long panicles. Some plants bear bisexual flowers. Male or bisexual plants may change completely into female plants after being beheaded. Fruit is a fleshy berry, oval to nearly round or somewhat pyriform or elongated club-shaped. Fruit has thin, waxy skin, which is green in colour when young, becoming light or deep yellow as it ripens. Flesh is succulent, yellow or golden-yellow or orange-red in colour, aromatic and sweet. Seeds look like pepper, about 5 mm long, black or grey-black in colour and attached to the flesh by a soft, white, fibrous tissue. All parts of the plant are rich in white latex.
Papaya's Behavior & Ecology
Papaya grows well in hot places and requires light and porous soil rich in organic matter for better performance. It is also capable of growing in marl, scarified limestone and other types of poor soils. However, it is very sensitive to water stagnation and even well-grown plants would be killed by root rot in excess moisture.
Papaya is normally propagated by seed. Seeds, extracted from ripe fruits, are washed to remove gelatinous seed covering (aril) and then dried. Dried seeds are dusted with fungicide to avoid damping-off, which is a common cause of loss of seeds. Rate of germination is high, if the seeds are planted as soon as they are extracted from the fruits. Papaya can also be grown from semi-hard woodcuttings, which need to be hardened off for a few days before planting. Air-layering is also practiced in a small scale to reproduce certain varieties.
Papaya's Relationship with Humans
Ripe fruits, available throughout the year, are eaten fresh and widely used in salads. Papaya juice, prepared from peeled fruit, is a delicious drink. In the Maldives, unripe fruits are used to prepare spicy curry whereas a special dish called “falho murubb’ is prepared by cooking young ripe fruit in sugar syrup. Fruits and leaves can be used to tenderize meat.
Carica papaya prefers tropical climates. Wild populations grow in open sites of deciduous tropical forests or tropical rain forests in well drained, deep soils with a pH of 5.5 to 7 (Vázquez-Yanes et al. 1999, Missouri Botanic Garden 2016).
Habitat fragmentation has been a continuous threat to the tropical rainforests, the natural habitat of Carica papaya, due to land use change. In Costa Rica, these forests have been reduced by 4.2% per year (1986–1991). In Mexico, a reduction of 1.8% was estimated during the decade of 1981–1992. Tropical forests in Los Tuxtlas, Mexico have shown extensive fragmentation, due to human activities (cattle pasture), losing up to 75% of its extent. In recent studies, wild populations of C. papaya in Veracruz were found to be threatened by habitat fragmentation, showing lower genetic diversity and higher differentiation in forest fragments than in continuous forests (Flores and Gerez 1994, Estrada and Coates-Estrada 1996, Sánchez-Azofelia et al. 2001, Mendoza et al. 2005, Chávez-Pesqueira et al. 2014).