New terms in PO

[Pankaj Jaiswal]

My comments are follow Leonore's.
-Pankaj

Leonore Reiser wrote:

> On Thu, 2 Sep 2004, Felipe Zapata wrote:
> 
> 
>>Cauline leaf:
>> From the definition it looks like it refers to a regular leaf. Only it
>>has a particular name because "is before flowering" and "lacks a
>>petiole".  Lacking a petiole shouldn't pose a problem as not all the
>>parts of leaf have to be present (we still follow the sometimes part of
>>rule, right?). So a leaf may or may not have petiole.  In regards to
>>"before flowering" I wonder if this event makes a "regular leaf" (in
>>terms of anatomy and structure) a different type of leaf. I don't think
>>so.  This is more like a...developmental stage term?
> 
> 
> This term typically refers to the leaves which are borne on the elongated
> inflorescence branches in Arabidopsis. It is a VERY commonly used term in
> desrcribing Arabidopsis both wild type and mutant form.They almost always
> have 'adult' characteristics.

I consider this as a generic leaf but present on the cauline internodes.
Going by the TAIR definition as follows it is an equivalent of "flag 
leaf" in cereal plants.
Def: Stem leaf, produced before the transition to flowering, lacking a 
petiole.

However, if there are more than one instances of this leaf in a plant 
(answer is possibly YES) , then we can create this as an instance of the 
leaf at the same level as
PO:0006340 : adult leaf
PO:0020103 : flag leaf
PO:0020043 : compound leaf
PO:0006338 : embryonic leaf
PO:0006339 : juvenile leaf
PO:0020042 : simple leaf



>>Rosette leaf:
>>Once again, from the definition, it looks like it refers to a regular
>>(normal) leaf growing in certain arrangement, not to a different type
>>of leaf.  If the internodes between leaves elongate or not, that's a
>>different issue.  Some plants grow characteristically as rosette plants
>>(e.g. plants in the high peaks), nonetheless the leaves are "normal
>>leaves".  If rosette leaf is introduced to POC, why not alternate leaf?
>>opposite leaf?
> 
> Again- this is a very commonly used term to describe leaves that are
> formed prior to elongation of the primary stem. Well, actually, I think
> Fred Hempell may have shown that some of these leaves are initiated before
> stem elongation. So maybe defining as leaves which are below the elongated
> internode.
> 

I think this refers to the generic leaf present in the Arabidopsis or in 
any other organism, often found in the region of stem, where internode 
elongation is either absent or minimal. In cases of Maize as Marty is 
suggesting, it is due to the defective in Gibberellic Acid synthesis, 
where possibly due to this effect the plant may never enters the "stem 
elongation growth stage". However, in case of Arabidopsis this is a 
normal phenomenon and so as in cabbage or many of the other Brassicales. 
These are definitely different than cauline leaves in terms of position 
which are present towards the top of the stalk/stem with elongated 
internodes also called as cauline region.

A generic definition of a rosette leaves is "A group of leaves arising 
closely together from a short stem, forming a radiating cluster on or 
near the ground".

Therefore, I would consider rosette leaves as synonym of the term 
PO:0009025 : leaf.



> 
>>Hypocothyl hook:
>>I am not what it refers to, but if it is indispensable...
>>
> 
> 
> Oh yes- it is indespensable- particularly when describing ethylene
> responses. Part of the so called triple response is hypocotyl hook
> curvature. This would be an example of a term that refers to a region
> (defined by a physiological response).
> Leonore
> 

In most of the descriptions I have found, if refers to the upper region 
of hypocotyl next to the cotyledons, found mainly in the germinating 
seeds of dicots only, that undergo epigeal type of germination. e.g. in 
many beans. However, in those seeds undergoing hypogeal type of 
germination, e.g. in peas, the hook forms in epicotyl and cotyledons 
stay in ground. In these cases it is called "epicotyl hook".

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=search&term=epicotyl+hook

Plant Cell Physiol. 2001 Sep;42(9):952-8 says:
...The intensity of the yieldin signal in the hypocotyls was highest in 
the apical pre-elongation region (the hook region) and decreased toward 
the elongated mature base indicating that the yieldin disappeared with 
the ceasing of cell elongation....

Physiol Plant. 2000 Feb;108(2):208-15.  suggests evidence of term usage 
hypocotyl/epicotyl hook.

more on epicotyl hook.
Photochem Photobiol. 1992;55(2):313-8.
Plant Physiol. 1996 Jan;110(1):163-70.

Going by the majority cases, it is part of a hypocotyl or rather it is 
the hypocotyl and the curved portion of the hypocotyl, which straigtens 
out once the cotyledons emerge from the ground/soil. Once it 
straightens, no one calls it s hook, it is hypocotyl. It is just a short 
phase of germination when the hypocotyl is maintained as a hook.

My suggestion is to create a synonym "hypocotyl hook" for hypocotyl.