Bertholletia excelsa - The Brazil Nut

Adaptation

The Amazon Rainforest can be a very harsh environment for any plant to grow in.  Water is one of the main resources required for life and growth, so the ability to maintain hydration is a quality that every plant must have in order to even begin growing.  The Amazon can receive as much as 120 inches of rainfall in one year, but with temperatures averaging from 80 to 90F during the day, water loss can become a very hazardous issue to plants on a daily basis.  One adaptation for B. excelsa is the thickness of the nut-bearing pod.  The thickness of this pod wall helps the fruiting body to not only maintain water for the seeds, but also shield the seeds for when the pods fall in order to be dispersed (see the Reproduction page!).  Flowering of the tree typically takes place towards the end of the dry season and into the wet season.  On average, the fruiting pods take about 15 months to develop after they have been set, and fall during January or February (part of the rainy season).  Once the seeds have been dispersed, they generally take 12 to 18 months to germinate.

 

The B. excelsa tree itself also has some necessary adaptations for life in the Amazon.  With such dense forestation throughout the entire Amazon region, plants must be competitive in order to get regular exposure to sunlight.  With the trees growing to be as tall as 200 feet, and with a crown of 100 feet in diameter, B. excelsa is one of the best competitors in the entire forest when it comes to sunlight.  This height allows the photosynthetic leaves of the plant to grow above most other trees, giving them the most direct exposure to sunlight.  The large crown of the tree is also a modification to allow maximum surface area for photosynthesis.  The branching in the crown of the tree is also much more spread out with more horizontal growth in a thin layer of branches, rather than more densely packed branching throughout the entire trunk of the tree (found in organisms such as Populus deltoides, the cottonwood tree).

 

To learn more, continue to the Nutrition page!

Peter Zepke of University of Wisconsin - La Crosse.  BIO 203 - Spring 2012.