Date: Mon, 20 Oct 1997 11:42:02 From: SCHLAUER@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg4057$foo@default> Subject: Re:Carnivorous Bromeliads
Dear Rand & al.,
> Is that not a Bromeliad that is in question by taxonomists, as well as
> Brocchinea, as far carnivorous plants are described?
This discussion was held on this list at least three times already.
As I have never failed to include my opinion in the past, I will
repeat it another time.
First, taxonomists do not have any problem with _Catopsis_ and
_Brocchinia_ as far as their assignment to Bromeliaceae is concerned.
The question if they are carnivorous is an ecological one (not to be
judged by taxonomists in the first line).
My personal answer to this question is a resolute NO!
The carnivorous syndrome requires the simultaneous or sequential
presence of at the very last the following mechanisms:
for the attraction of animal prey
for the capture and eventual killing of prey
for the digestion of prey
for the uptake of digestion products
The passive digestion (by microorganisms) of Bromeliaceae readily
*dis*qualifies them as cps. The microorganisms and *not* the plants
are carnivorous in this case. The plants are merely opportunists. As
many Bromeliaceae are adapted to this particular mode of life
(forming rosettes that accumulate water and all kinds of debris that
are able to enter and inable to leave the cistern), they are to be
appreciated just as simply *bromeliads* but not at all as cps.
Likewise, _Roridula_, _Byblis_, and some Sarraceniaceae cannot be
considered true carnivores. But in these, at least a more or less
close affinity to carnivorous plants and similar trapping mechanisms
are present. Thus, I would call the latter groups sub-carnivorous.
Some of them have developed remarkable mechanisms to bridge their
digestive gap (much more elaborate symbioses than just with lousy
microorganisms that are virtually ubiquitous where dead animal matter
is around).
Who is going to perform the decisive digestion test with _Ibicella_?
> Just asking. Is there any research being done on these plants that would
> _definitly_ put them in the carnivorous area?
No enzymes, no cps. All research I know so far puts them clearly *out*
of this area. Perhaps this opinion sounds a little too severe, but
there is absolutely no other way to prevent almost half of the plant
kingdom to be called carnivorous. Believe it or not, there are really
*many* plants with sticky leaves or other "trapping" mechanisms
around, none of which even remotely approaching as elaborate
adaptations to heterotrophy as the cheapest _Drosera_ you can imagine.
Kind regards
Jan
This archive was generated by hypermail 2b30 : Tue Jan 02 2001 - 17:31:12 PST