In the case of cacti, the pressure is toward producing fast-growing "heavy
drinkers". Most commercial growers raise cacti from seed in the greenhouse.
There the seedlings are watered and fertilized almost to the point of rotting,
the intent is to produce sales-ready plants as soon as possible. Smaller,
slower growing seedlings are overtopped and squashed in the crowded seedling
flats. The genes which allow certain cacti seedlings to grow rapidly
originate from nature. The genes weren't produced in cultivation. But
certain alleles and gene combinations are selected for under cultivation.
These may make a good greenhouse cactus, but may make for an unhealthy plant
in habitat. These "heavy drinking" genes might be unsuitable in the wild
except for a plant which germinates in a rare moist crevice on the shaded
north side of a hill.
Individual growers may treat their cacti differently, but for most
cacti, the vast majority of plants in cultivation originate from commercial
growers who've selected the seedlings for quick growth with lots of water.
In the case of CP I'm not sure if there is such a dramatic pressure to
adapt to unnatural conditions under cultivation. But for North
American and Australian CP there may be pressure to do away with a
dormant period. Plants which grow year-round are great for cultivation,
but probably won't last long in a seasonal environment. If you grow
enough plants from seed you may get a few which don't observe a
complete dormancy under cultivation.
>
> >
> > Anyway, it would probably take a very long, long time before
> > evolution makes cultivated plants unsuited for the wild (not
> > counting hybrids, sports and other wierdies like that; and
> > natural selection would make fast work of them anyway.) Now, if
> > we can only ensure that there will be somewhere wild in a couple
> > thousand years!
>
> Not necessarily true. An extreme example: You dig up 1000 plants
> of species X and take them home. One of them survives because it has the
> particular genetic makeup to survive your conditions. In one generation,
> you have selected for a plant that grows best under your conditions. That
> plant may or may not be suitable for reintroduction at some future date.
> Perhaps it would have died out before producing any progeny if left in
> the wild. This is obviously an extreme scenario, but more subtle
> variations might be happening with our collections. We pollinate a
> particular species of plant, and plant the thousands of seeds. In many
> cases, we only have room to keep a few of the seedlings, and therefore we
> keep the healthiest, or biggest, or whatever. A very few generations of
> this and we could end up with a very homogenous population of that
> species.
Well said! I also worry about the pollinators and other symbiotic organisms.
How many CP growers also raise the natural pollinators of their plants?
Are the pollinators known? Some CP may have generalized pollinators, but
plants with more specialized flowers (Byblis, Pinguicula, Utricularia) may
have specialized pollinators. What is the rarity of these insects?
I've heard that Roridula has co-evolved with certain insects which feed
on the insects trapped in the plant's sticky hairs. Could Roridula or these
special insect feeders survive long in the wild without each other?
Michael Chamberland