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Friday, 29 May 2009 06:33 |
A popular tropical fruit, the pineapple, Ananas comosus, of the Bromeliaceae family
The pineapple (Ananas comosus) is a tropical plant and fruit (multiple), native to Uruguay, Brazil, Puerto Rico, or Paraguay. It is a medium tall (1–1.5 m) herbaceous perennial plant with 30 or more trough-shaped and pointed leaves 30–100 cm long, surrounding a thick stem. The pineapple is an example of a multiple fruit: multiple, spirally-arranged flowers along the axis each produce a fleshy fruit that becomes pressed against the fruits of adjacent flowers, forming what appears to be a single fleshy fruit. The leaves of the cultivar 'Smooth Cayenne' mostly lack spines except at the leaf tip, but the cultivars 'Spanish' and 'Queen' have large spines along the leaf margins. Pineapples are the only bromeliad fruit in widespread cultivation. It is one of the most commercially important plants which carry out Crassulacean acid metabolism, or CAM photosynthesis.
The fruitlets of a pineapple are arranged in two interlocking spirals, eight spirals in one direction, thirteen in the other; each being a Fibonacci number. This is one of many examples of Fibonacci numbers appearing in nature.
The natural (or most common) pollinator of the pineapple is the hummingbird. Pollination is required for seed formation; the presence of seeds negatively affects the quality of the fruit. In Hawaii, where pineapple is cultivated on an agricultural scale, importation of hummingbirds is prohibited for this reason.
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