Watermelon (Citrullus lanatus) is a vine-like (scrambler and trailer) flowering plant originally from southern Africa. Its fruit, which is also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind (exocarp) and fleshy center (mesocarp and endocarp). Pepos are derived from an inferior ovary, and are characteristic of the Cucurbitaceae. The watermelon fruit, loosely considered a type of melon – although not in the genus Cucumis – has a smooth exterior rind (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually deep red to pink, but sometimes orange, yellow and even green if not ripe).
For commercial plantings, one beehive per acre (4,000 m² per hive) is the minimum recommendation by the US Department of Agriculture for pollination of conventional, seeded varieties.
Because seedless hybrids have sterile pollen, pollinizer rows of varieties with viable pollen must also be planted. Since the supply of viable pollen is reduced and pollination is much more critical in producing the seedless variety, the recommended number of hives per acre, or pollinator density, increases to three hives per acre (1,300 m² per hive). Watermelons have a longer growing period than other garden plants and can often take up to 85 days of growing to mature.
A watermelon contains about 6% sugar and 91% water by weight. As with many other fruits, it is a source of vitamine C.
The amino-acid citrulline was first extracted from watermelon and analyzed. Watermelons contain a significant amount of citrulline and after consumption of several kilograms, an elevated concentration is measured in the blood plasma; this could be mistaken for citrullinamia or other urea cycle disorders.
Watermelon rinds, usually a light green or white color, are also edible and contain many hidden nutrients, but most people avoid eating them due to their unappealing flavor. They are sometimes used as a vegetable In China, they are stir-fried, stewed or more often pickled. When stir-fried, the skin and fruit is removed, and the rind is cooked with oliove oil, chili peppers, sugarand rum. Watermelon juice can be made into wine.
Watermelon is mildly diuretic and contains large amounts of carotenoids. Watermelon with red flesh is a significant source of lycopene. Preliminary research indicates the consumption of watermelon may have antihypertensive effects