MadSci Network: Botany

Re: why do some cell names have different names when they're the same thing?

Date: Sun Nov 14 18:42:25 2004
Posted By: David Hershey, Faculty, Botany, NA
Area of science: Botany
ID: 1100462981.Bt

Plastids are organelles rather than cells. Technically, a leucoplast is not 
the same as an amyloplast. There are many different types of plastids. The two 
main categories are based on color. Chromoplasts are colored. Leucoplasts are 
colorless. Chromoplasts that contain chlorophyll are usually green and are 
termed chloroplasts. 

Leucoplasts can be amyloplasts, elaioplasts (oil storage plastids), 
proteinoplasts or proteoplasts (protein storage plastids), proplastids 
(precusors to plastids) or etioplasts (proplastid arrested in development due 
to lack of light).

What stimulated your question seems to be that some authorities defined 
leucoplast incorrectly. The American Heritage Dictionary of the English 
Language defined leucoplast as "A colorless plastid in the cytoplasm of plant 
cells around which starch collects." That is incorrect in two ways. A 
leucoplast will not necessarily contain starch, and the starch always forms 
inside a plastid, not around it. There are hundreds of plant misconceptions in 
the literature.

There are several other reasons there are duplicate names for the same thing 

1. Terms become obsolete but remain in use. For example, geotropism and 
gravitropism describe the same response but geotropism is considered obsolete 
and inaccurate because the response is to gravity not the earth (geo). 
However, geotropism persists in the literature.

2. There are sometimes common versions of scientific terms, for example 
amyloplasts are often called starch grains.

3. Some scientists coin new terms when existing terms are sufficient. For 
example the term skototropism was termed to describe the negative phototropism 
of certain vine stems. That may also be the case with the synonymns 
proteinoplasts or proteoplasts.

There are also sometimes multiple definitions for the same term. For example, 
at least one scientist defines a leucoplast as a distinct kind of plastid 
rather than simply as colorless plastids (see last reference). 

I agree with you that duplicate terms for the same thing are frustrating but 
I'm not sure it is avoidable. One solution might be to create an international 
scientific dictionary with one definition for each term and one term for each 
concept. We have an International Code of Botanical Nomenclature and an 
International System of Units so it might be possible. However, dictionary 
publishers might be against it.


Incorrect definition of Leucoplastid

Correct definition of Leucoplast

Avoid Misconceptions When Teaching about Plants


Carde, J.P. 1984. Leucoplasts: a distinct kind of organelles lacking typical 
70S ribosomes and free thylakoids. Eur J Cell Biol.  34(1):18-26. 

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