Phyllotaxy and the kiwi

Dan Sorensen 814-757-9382 DSORENSE at A1.PSUPEN.PSU.EDU
Sun Jul 31 01:24:42 EST 1994


 
In article <319tju$sf3 at nermal.cs.uoguelph.ca> jagerrat at uoguelph.ca (John A Gerra
>I was just wondering about general phyllotaxy in relation to a specific
>plant, Actinidia arguta, that is growing in my garden. ....  In terms of leaf
>placement on its stems, there seemed to be no discernable pattern.  Nothing!
>Is this common? There is no constant distance between leaves and no
>preference of side. Leaves will sometimes appear on the same side of the stem
>for a while, then switch, or appear bunched together.   I found three leaves
>in the space of one centimetre, two seemingly opposite and the other slightly
>further along.  There does not seem to be a spiral arrangement at work
>here either.  Most plants seem to key quite well into alternate or
>opposite leaved types and I hadn't really thought a fruiting vine would
>place it's leaves so randomly.
>Another thing I find odd about this plant is that it has a history of
>true dichotomous branching (in our garden, at least).  The stem, if you
>follow the stem from one branch to two, begins perfectly round.  It then
>widens and into a flattened (on the long sides) oval.  A groove then appears
>down the centre of the stem.  This deepens until the stem has divided into
>two, each half twining like a normal stem.   This struck me as weird.
>Is this plant's apparent lack of a concrete way of organizing it's stem
>allowing it to branch this way?  Are kiwi fruit plants sympodial,
>monopodial, or something else.  What is happening?!
 
I have about a hundred Actinidia arguta and 15 A. kolomikta plants growing
in my backyard. On ALL of my plants the leaves are alternate along the stem.
Is it possible that some leaves were lost to wind or other physical damage?
If not this is definitely an atypical specimen.
 
Regarding the unusual dichotomous branching, I have seen this fairly often
but it also isn't normal.  Stems that do this have yet to survive the winter
here in NW Penna. so I suspect the nutrient and/or water flow is somehow
affected.
 
I wonder if this plant is a named variety or a seedling?  Has it ever
produced flowers or fruit?  I wouldn't be surprised if it hasn't.  This
sounds like one mixed up kiwifruit plant.
 
Dan Sorensen   dsorense at psupen.psu.edu
Russell, PA
 





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