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Secret sex life of papaya

A short lived, fast-growing tree, papaya or pappali, as it is called in Tamil, is really an overgrown herb. It bears fruit within a year of planting and quite abundantly too, especially when the cold season is about to set in.

Papaya is dioecious, which means there are separate male and female trees and naturally it is the female which bears fruits. It is virtually impossible to say if the seed that is sown would grow into a male or female tree. And, therefore, it will be prudent to sow quite a few seeds, though, of course, one per hill is the norm. One thus can be sure that at least one of them would grow into a male, thus ensuring pollination and fertilisation, the two antecedent processes leading to fruit-bearing.

An interesting thing about papaya is that some of the trees are hermophrodite, i.e. the same tree is both male and female, and what is far more interesting is that occasionally a male tree changes into a female. Sometimes, if by accident all the seeds sown grow into male trees, the whole purpose of the project comes into jeopandy and at such times, some of the male trees could be induced to change into female trees, by decapitation, i.e. by cutting off the crown of leaves by a chopper.

Pawpaw or the papaya, as it is more familiarly known to us in Chennai, is a native of tropical central America. It is a soft-wooded tree bearing a large crown of big palmately parted leaves on a long, hollow stem. The bark is marked by conspicious diamond-shaped scars of fallen leaves.

On rotting, these scars on the trunk disappear and in their place, diamond-shaped hollow spaces are seen. These spaces are surrounded by a stiff tissue made up of water-conducting tubes which in technical parlance are called xylem vessels. These align with a patch of soft tissue, just short of entering the leaf proper. The hard element is called leaf trace and the soft patch, a leaf gap. A well-rotted papaya trunk makes an excellent study material for understanding the anatomical organisation of the main waterway inside a tree trunk.

The fruit is melon-like. When unripe, the fruit has a green coat but as it ripens, it turns yellow. Inside, there is a large mass of succulent, salmon pink flesh. The flesh is divided into a five-chambered cavity, which, however, becomes one-chambered by the disintegration of the walls separating them. Adhered to those walls are numerous round, winkled black seeds, but as we said earlier, the walls dividing the cavity into five chambers disintegrate so much so the seeds are held loose in the cavity. However, many cultivated varieties are seedless. The flesh is sweet to taste, with a smell that is disagreeable to some.

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The smell comes from the presence of a protein digesting-enzyme, called papain. Actually, there is more of this enzyme in the latex, a milky fluid that flows out when a leaf is pulled out or when the unripe fruit is incised. The presence of papain is made use of by the owners of mutton stalls. They wrap the mutton with papaya leaves so that it remains tender, a quality that improves its marketability. Papain is also used in making chewing gum.

Pappali is of great medicinal value. The milky juice obtained from an unripe fruit is used as a cosmetic to remove freckles and other blemishes from the skin. The ripe fruit is an excellent diuretic. The green parts and seeds contain an alkaloid called carpeine, used as a heart stimulant and amoebicide.

The botanical name of papaya is Carica papaya.