Re: Are all plants autotrophes?

  Interesting question Iain,
    I learned that all plants produced their own food through the process 
of photosynthesis, taking in carbon dioxide,in the presence of light and 
chlorophyll, making gluecose and giving off some oxygen and water. I would 
have to say, yes, as autotrophs produce their own food. Photosynthetic 
Autotrophs are at the base of the food chain and all other animals rely on 
them for food. 
    I will leave you to wonder a little. There are some animals one-celled 
that can produce their own food. How do these organisms compare to 
photosynthetic autotrophs such as plants?
    Hey, and what about a venus fly-trap? Autotroph?

A couple of websites to check out:

http://niko.unl.edu/bs101/notes/nopix6.html#Photosynthetic_Autotrophs2

http://teach.eac.cc.az.us/curtiss/bchap7.htm


David Kirschtel adds:

Using Raven, Evert and Johnson's "Biology of Plants" as
source: there are several parasitic and saprophytic angiosperms. The
parasitic species such as Dodder (Cuscata cuspidata) and and Squaw root
(Conophilis americana) have some chlorophyll and appear yellowish but
obtain most of their carbohydrates from their hosts, magnolia and oaks,
respectively. Indian pipe or Pipsissewa(sic?) (Monotropa uniflora) is
achlorophyllous, appearing white, and is thus incapable of any
photosynthesis. Carbohydrates appear to be obtained via mycorrhizal
fungi which are also associated with another, photosynthetic plant
(according to REJ, although most of my other references state that the
plants are truly saprophytic). If you use a somewhat broader definition
of "plant" an argument can be made to include the phycomycote/oomycote 
fungi as non-autotrophic plants. Given that they have cellulosic cell
walls, they are most likely more closely allied with the algae-plant
lineage than with the true fungi. Within the algae there is a range of
metabolism from obligately autothophic to facultatively phagotrophic
[Bold and Wynne, "Introduction to the Algae"], sometimes even within a
single species depending on the life stage, e.g. the "red-tide"
dinoflagellate, Pfeisteria.

With the venus fly-trap, the carnivorous "behaviour" is primarily to
obtain nitrogen (amino acids) and similarly for the other carnivorous
plants. So, strictly speaking, this makes the plants facultatively
auxotrophic.