In article , NOiwEMAIL wrote:
Sat, 12 Jun 2004 18:16:29 GMT Christopher Green wrote:
The answer is a merely practical one: grafting is done when either:

* This is a good means of propagating a desirable plant; for example,
if the plant does not tend to root from cuttings or layerings.

* The rootstock has desirable qualities that the plant, rooted on its
own, would not have. These may include resistance to disease or pests
(as in grapes) or growth regulation (as in dwarf fruit trees).

I do not know what layering is. I know cuttings. Can you describe layering..

Cut a narrow ring around the branch (like ring-barking) bend it down
to the ground and "plant" it so the cut is under ground. Wait until
roots form from the portion above the cut then chop it off below the
cut and plant the top section normally.

Off topic. I now like my bush cherries prunus tomentosa. But for the past 2 years have been unable
to get a single seedling. I wonder if they require going through the gut of a bird?

I wonder why any plant would evolve to the point where they depended on the gut of a bird rather
than viability without the gut. This gut dependency strikes me as a flaw in the theory of Darwin
Evolution. A plant seed has the greatest survivability if it had no bird gut dependency so that if
the bird ate the seed or did not eat the seed would be viable in either case.

Some plants won't grow under the parent, so it's advantageous for them
to move away. Also, if you want to take over the world you'll find it
hard to do if you just stay in one place. :-)

But I take your point, and I suspect the answer is that most seeds
*can* be made to grow without passing through the gut of an animal.
However, if the plant needs to be dispersed to avoid the consequences
of allelopathy, then, if it is too heavy to just blow around on the
wind, it needs something to carry it. If that something is an animal
that eats the fruit, then the seed needs to be able to survive passage
though the gut. And if it is to do that successfully, it probably
needs to be fairly resistant to "normal" processes conducive to
germination for the time being. Passing through the gut may well
neutralise this "dormancy" factor, thus enabling the seed to germinate
successfully before it dies. (Plants in moist environments, such as
the tropical rainforests, often seem to have recalcitrant seeds which
both die quickly in nature and are difficult to store even with the
best of technology.)


Cheers, Phred.

--
LID