Gas Exchange
Thursday, December 11, 2008 at 9:10AM
[chuck] in Brosimum alicastrum, Science, ecophysiology, infra-red gas analyzer, photosynthesis

I learned a lot about Brosimum alicastrum when I did my doctoral research (e.g. see The Curious Case of Brosimum alicastrum and MAB Report). I looked at the growth and reproduction of natural populations, conducted experiments on seedling establishment, and developed a matrix model to assess the long-term demographic impact of seed harvesting.  I also took greenhouse-grown seedlings into the laboratory and measured their photosynthesis, respiration, and transpiration under different light levels. Main finding: seedlings are very shade tolerant but they can also respond to abrupt changes in light levels (e.g. treefalls and canopy gaps).

I am basically a field person, but this high-tech lab stuff was quite fun and provided an amazing amount of detail about seedling physiology.  [NOTE: The Brosimum seedling is resting on top of a dictionary (Webster's 1964 College Edition; I still have it), with its terminal leaf enclosed in a brass and plexiglas assimilation chamber. Light source is a Sylvania 1000 watt metal arc lamp.  Flow rates were measured using a Beckman Model 865 infrared gas analyzer, two Wosthoff G27/3F gas mixing pumps, and an EG&G dew point hygrometer].

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