Date: Wed, 28 May 1997 10:55:58 -0400 (EDT) From: Oliver T Massey CFS <massey@hal.fmhi.usf.edu> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg2093$foo@default> Subject: Re: cp roots
> > Most cp's are wetland plants and can live in water-saturated soils,
> > but it is my understanding many will die if they are kept in
> > waterlogged soils for an extended period. My question to everyone
is:
> > do some cp possess a means for delivering oxygen to their roots, like
> > aquatic plants do (aerenchyma tissue?), or do they simply have a high
> > tolerance for anoxic soils?
> No. Sounds likely. Nepenthes, Darlingtonia and Heliamphora are
> not tolerant - that's for sure.
> > If they do not have aerenchyma, then this implies they cannot
> > survive in saturated soils in perpetuity and must spend at least
> > part of they year with their roots above the water table.
AND:
>>> I have grown them in tables with a water level at soil level
>>>during a few years (during the whole summer, the tables are dry during
>>>winter).
>>>When repotting them, I noticed a typical smell from the soil, due >>>to the
lack of oxigen in the soil. The roots were sometimes black >>>and brittle
(dead).
>>> The plants will adopt their roots to >>>the level where they can find the
>>>right amount of water and oxigen. If the water level is very high they will
form >>>shallow roots, with a deeper
>>>water level, the roots will also grow deeper.
I believe that the explanation may be a bit more complicated. For the Sarrs. I
have plants that are many years old that regularly grow and sustain roots in
the water trays. These trays are kept constantly filled with water, maybe 1
and 1/2 inches in summer, and 1/2 inch or less in winter. And of course, the
biggest forms of S. minor and S. psittacina are found in the Okee swamp,
growing on sphagnum mats floating on water. Not only saturated, but almost
naturally hydroponic. For the Neps., I have some that grow roots into water
trays with abandon (mainly those @#$% hybrids), while others keep their roots
high above the water level. Darlingtonia from published reports appears to be
fine "waterlogged". I haven't grown it down here but it appears that it
actively grows in streams and along stream banks.
This does not refute the comment about oxygen depleted soils, however. I don't
believe any CP like anoxic soils. In culture an easy way to loose a Sarr. is
to plant it and leave it for several years (regardless of water level) without
repotting and discarding the old rotting soil material. The point may be that
in nature even the Okee swamp is not anoxic.
IMHO, the biggest issue is the breakdown of the potting medium that may be
hastened by high water levels. In the wild, this breakdown simply does not
occur in the same way it does in a small pot. An interesting question is
whether small outdoor bogs suffer the same breakdown and collapse as do
individual pots? I would hate the idea of "repotting" a bog of several cubic
yards of rotton peat! HA
Tom in Fl
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