> I was wondering about the carnivorous standing of both these plants - are
> they insectivorous or not? What digestive enzymes do they test for to prove
> they are carnivorous? Does anyone know any journal articles that discuss
> these tests and their results for any of the CP's? Thanks for any help or
> comments you may have.
The whole rumour about carnivory in Martyniaceae (Pedaliaceae p.p.)
is based on a single Italian article published very early this
century claiming that the leaves of _Ibicella_ were able to dissolve
protein (cheese and that like). Nothing similar was ever published
about _Proboscidea_. However, generic (and even family)
circumscriptions have been changed several times in _Ibicella_, and
it is possible to buy the plants as Proboscidea or Martynia as well.
Unfortunately, it is much easier to obtain _Proboscidea louisianica_
than _Ibicella lutea_ (syn. Proboscidea lutea, Martynia lutea), and
the cp status has therefore been extended to the first species by
some clever horticulturists. Nobody seems to have tried to reproduce
the experiment or even to improve the test in terms of scientific
rigour, but nevertheless many authors claim to know that _Ibicella_
is carnivorous. The situation is very similar in _Roridula_ but here
the opposite is claimed, based on the single observation by F.E.Lloyd
that the secretion of this plant is resinous and not mucilaginous in
nature (which is correct), and that it can therefore not be sticky
(which is wrong, as all growers of these plants will confirm). The
digestive properties of _Roridula_ were tested by the same cheese-test
like in _Ibicella_ but as both investigations were published before
Lloyd, and he has commented _Roridula_ (with a "NO" lable), _Ibicella_
remained "unkilled" as a cp.
I would suggest to test the carnivorous properties in both genera
with enzymic assays (chromogenic peptide analogues as substrates in
a colorimetric test). As long as the proteolytic capabilities are
neither confirmed nor disproved, simply nothing can be stated with
any certainty about carnivory in these "candidates".
Kind regards
Jan