Thursday, June 30, 2011

Internodes as Storage Organs

Plants utilise many parts of themselves for food storage, which are often used as crops in agriculture: stem tubers in potatoes, leaf petioles in celery, leaves in onions, roots in carrots and turnips. These examples have been artificially modified by breeding for maximum storage, but considerable examples exist naturally, as anyone who has tried to remove the impressive tap roots of a dandelion (Taraxacum officinale) from flower beds will testify.
Silver weed, Argentine anserina
Large roots, leaves and stems are obvious candidates for storage. Yet plants often use less obvious structures, often to great benefit. Silverweed (Argentina anserina) is a very common plant of many habitats, from hegderow to sand dunes, so common that it can become a troubelsome weed in cultivated soil. It can spread quite rapidly using stolons, producing new plants or ramets at then end of each stolon. While the obvious purposes of the stolon internode between clones are to space out the plants and transport resources, it has been shown that the internodes act as storage organs (1). Juvenile, unrooted ramets were cut from stolons with and without the preceding internode. All ramets with the internode survived, while only 37% of those without did. Internodes that were left attached also decreased in dry weight over time, showing their use as storage organs.

  1. Stuefer and Huber, 1999. Ecology Letters 2 pp. 135-139

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