meristematic apical cell

[planteome-user]

Moss Ontology has requested the term '''apical cell'''. Apical growth in byrophytes and some non-seed vascular plants is via division of a single cell at the tip of the shoot apical meristem (or root apcial meristem, in vascular plants)

We already have the term '''apical cell (PO:0004000)''', which is an embryonic cell: "An embryonic plant cell that is the uppermost cell formed after the first division of the zygote." The embryonic apical cell can also be found in non-angiosperms. Suggest renaming PO:0004000 '''embryonic apical cell''' for clarity and using the name '''apical cell'''for the term described below. May want to obsolete PO:0004000 and replace with the two new terms, to avoid confusion in the names.

Proposed def. of apical cell: A single meristematic cell at the tip of a shoot apex or root apex

Comment: Occurs in bryophytes and some pteridophytes, where apical growth results from division of a single meristematic cell located at the tip of the apical meristem, rather than from a population of meristematic cells located at the tip of the apical meristem. May be tetrahedral shaped, with three (in shoots) or four (in roots) cutting faces, or wedge shaped with two cutting faces (in non-vascular leaves).

Reported by: rlwalls2008

Original Ticket: obo/plant-ontology-po-term-requests/303

[planteome-user]

Do we need separate terms for sporophytic apical cell and gametophytic apical cell?

gametophytic apical cell: A meristematic cell at the apex of a gametophore or non-vascular leaf.
Comment: Occurs in mosses and other bryophytes. participates_in gametophytic phase

sporophytic apical cell: An apical cell that is part of a shoot apical meristem of a plant in the sporophytic phase.
Comment: Occurs in Pteridophytes (and in the sporophyte of bryophytes?). participates_in sporophytic phase

Original comment by: rlwalls2008

[planteome-user]

Moss ontology also requested shoot apical cell and phyllid apical cell.

Proposed names and definitions:

gametophore apical cell: A gametophytic apical cell at the tip of a gametophore.

OR shoot axis apical cell: An apical cell at the tip of a shoot apical meristem. (could apply to mosses and ferns)

Comment: Divides to produces leaf initial cells and other stem tissues.
part_of shoot apical meristem

phyllid apical cell: A gametophytic apical cell at the tip of a non-vascular leaf.
Comment: Divides to produce non-vascular leaf tissues.
part_of non-vascular leaf

Original comment by: rlwalls2008

[planteome-user]

We probably do need to separate gametophytic apical cell and sporopohytic apical cell. Then in the latter, shoot, root and leaf.

Original comment by: dws409

[planteome-user]

At the POC meeting on 4-28-11, there was an extensive discussion, continuing from the week before, about whether we should keep the term 'apical cell' to refer to the very tip or apical cell in an angiosperm leaf or other structure that does not have apical growth. The problem of adding a generic term for an apical cell is that it would cause confusion, since there is not really a single cell at the tip of a vascular leaf or an apical meristem in most vascular plants. For cells at the leaf apex (PO:0020137) and leaf tip (PO:0025142), we can use the existing PO terms. We decided to go with the proposed changes below and perhaps reconsider the issue of general term 'apical cell' in the future.

Proposed changes:

Rename PO:0030007 "meristematic apical cell".

Append "meristematic" to the names of all the descendent terms except embyronic apical cell.

Use always_in and never_in taxon relations to help clarify which taxa these are from (once those relations are added - for now use taxon subsets).

Revised new def'n: A single meristematic cell at the tip of a shoot axis apex, leaf apex, root apex or thallus apex, in a plant structure where apical growth occurs.

Also, we should add a term for protonema apical cell.

Original comment by: rlwalls2008

[planteome-user]

If we keep the name meristematic apical cell, and append the word meristematic to the names of all descendents, it should also go in embryonic apical cell (embryonic meristematic apical cell), because embryonic apical cell will be a child of meristematic apical cell.

However, changing the name to meristematic apical cell may not really solve the problem. If someone sees "shoot meristematic apical cell" or "root meristematic apical cell", that is not enough information for them to determine that this is not to be used for a cell that is part of an apical meristem in an angiosperm. They have to read the definitions!

Perhaps it is better to use the original names with a slightly modified definition:

A single meristematic cell at the tip of a shoot axis apex, leaf apex, root apex or thallus apex, in a plant structure where apical growth occurs from a single cell at the tip of the structure.

Original comment by: rlwalls2008

[planteome-user]

Suggest a somewhat more succinct definition:
A single meristematic cell at the tip of a plant structure where apical growth occurs.

Comment:
Occurs in only bryophytes and some pteridophytes, at the tip of a shoot axis apex, leaf apex, root apex, thallus apex, or protonema. This term is only used when apical growth results from division of a single meristematic cell located at the tip of an apical meristem or plant organ, rather than from a population of meristematic cells located at the tip of an apical meristem. May be tetrahedral shaped, with three (in shoots) or four (in roots) cutting faces, or wedge shaped with two cutting faces (in non-vascular leaves or thalli). An apical cell may be established upon germination of a spore or upon the first cell division of an embryo or later.

Original comment by: rlwalls2008

[planteome-user]

I prefer the more succinct definition.

Suggest slightly modified comment, for clarity:
Apical cells occur only at the tip of a shoot axis apex, leaf apex, root apex, thallus apex or protonema in bryophytes and some pteridophytes. Apical growth results from division of a single meristematic
cell located at the tip of an apical meristem or plant organ, (rather than
from a population of meristematic cells located at the tip of an apical
meristem). The apical cell may be tetrahedral shaped, with three (in shoots) or four (in
roots) cutting faces, or wedge-shaped with two cutting faces (in
non-vascular leaves or thalli). Citation?

An apical cell may be established upon germination of a spore or upon the first cell division of an embryo or
later.

Original comment by: cooperl09

[planteome-user]

I still think it is better just to call it apical cell, but if we are going to change the name, I suggest using apical meristematic cell, instead of meristematic apical cell. In the PO, we general construct names such that he modifier comes first and the parent term comes last. In this case, meristematic cell is the parent, and apical is the modifier.

Original comment by: rlwalls2008

[planteome-user]

Meristematic apical cell (PO:0030007) was accepted at the POC meting on 5-10-11, using definition and comment from below.
synonyms: apical cell and apical initial

Original comment by: rlwalls2008

[planteome-user]

At the POC meeting on 5-10-11, we agreed that root meristematic apical cell (PO:0030008) should be part_of root tip, rather than part_of root apical meristem, to avoid confusion with meristematic cells in the RAM of a plants that do not have an apical cell.

For the same reason, shoot axis meristematic apical cell (PO:0030010) should be part_of shoot apex, rather than part_of SAM.

Original comment by: rlwalls2008

[planteome-user]

The following new descendents of meristematic apical cell were approved at the POC meetings on 4-26-11 and 5-10-11.

gametophyte meristematic apical cell (PO:0030014): A meristematic apical cell that is part of a whole plant in the gametophytic phase.
Comment: Occurs bryophytes and pteridophytes.
intersection_of: is_a apical cell, intersection_of: participates_in gametophytic phase

sporophyte meristematic apical cell (PO:0030015): A meristematic apical cell that is part of a whole plant in the sporophytic phase.
Comment: Occurs in pteridophytes and the sporophyte of bryophytes.
intersection_of: is_a apical cell, intersection_of: participates_in sporophytic phase

thallus meristematic apical cell (PO:0030025): A gametophyte apical cell that is part of a thallus.
part_of thallus

root meristematic apical cell (PO:0030008): A sporophyte meristematic apical cell that is part of a root tip.
comment: Occurs in the sporophytic phase of pteridophytes.
part_of root tip

shoot meristematic apical cell (PO:0030009): A meristematic apical cell that is part of a shoot system.
comment: May occur in shoot axes or leaves of bryophytes or ferns.
part_of shoot system

gametophore meristematic apical cell (PO:0030019): A shoot meristematic apical cell that is part of a gametophore.
comment: Occurs in the non-vascular shoot system of the gametophyte of mosses and leafy liverworts.
intersection_of: is_a shoot apical cell, intersection_of: part_of gametophore

leaf meristematic apical cell (PO:0030011): A shoot meristematic apical cell that is part of a leaf apex.
comment: Occurs in the non-vascular leaves of bryophytes and the vascular leaves of some ferns. Only in plants where leaf growth is apical.
part_of leaf apex

non-vascular leaf meristematic apical cell (PO:0030013): A leaf meristematic apical cell that is part of a leaf apex of a non-vascular leaf.
comment: Occurs in the non-vascular leaves of bryophytes, which grow by division of a single, wedge-shaped apical cell with two cutting faces.
part_of non-vasucular leaf; synonym: phyllid apical cell

vascular leaf meristematic apical cell (PO:0030012): A leaf meristematic apical cell that is part of the leaf apex of a vascular leaf.
comment: Occurs in vascular leaves of some ferns in their sporophytic phase.
part_of vascular leaf

shoot axis meristematic apical cell (PO:0030010): A shoot meristematic apical cell that is part of a shoot apex.
Comment: Divides to produces leaf initial cells (if leaves are present) and other stem or branch tissues.
part_of shoot apex

gametophore axis meristematic apical cell (PO:0030023): A shoot axis meristematic apical cell at the tip of a gametophore axis.
Comment: Occurs at the tips of the stems and branches of bryophytes.
part_of gametophore axis; synonym: cauloid apical cell, non-vascular shoot axis apical cell

vascular shoot axis meristematic apical cell (PO:0030024): A shoot axis meristematic apical cell at the tip of a shoot apex in a shoot system that has as part vascular tissue.
Comment: Occurs in some ferns in their sporophytic phase.
participates_in sporophytic phase; synonym: fern shoot axis apical cell

seta meristematic apical cell (PO:0030016): A shoot axis meristematic apical cell at the tip of a seta.
Comment: Ceases being an apical cell when the sporangium begins to develop.
part_of seta

protonema meristematic apical cell (PO:0030046): A gametophytic apical cell that is part of a protonema.
part_of protonema

embryo apical cell (PO:0025284, replaces PO:0004000): A meristematic apical cell that is part of a plant embryo and is the uppermost cell formed after the first division of a zygote.
Comment: For plants that grow via an apical cell in their sporophytic phase, the embryonic apical cell may remain meristematic throughout the plant's life.
part_of embryo, develops_from zygote; synonym: embryonic meristematic apical cell

Each of the above terms has the synonyms xx apical cell, and xx apical initial.

Closing this item.

Original comment by: rlwalls2008

[planteome-user]

• summary: apical cell --> meristematic apical cell
• priority: 8 --> 1
• status: open --> closed-accepted

Original comment by: rlwalls2008

[planteome-user]

The Moss Ontology has requested caulonema, chloronema and rhizoid apical cell.

Proposed definitions:

caulonema meristematic apical cell: A protonema meristematic apical cell that is part of a caulonema.

chloronema meristematic apical cell: A protonema meristematic apical cell that is part of a chloronema.

rhizoid meristematic apical cell: A gametophytic meristematic apical cell that is part of a rhizoid.

Original comment by: rlwalls2008

[planteome-user]

• priority: 1 --> 8
• status: closed-accepted --> open-accepted

Original comment by: rlwalls2008

[planteome-user]

caulonema meristematic apical cell (PO:0030081), chloronema meristematic apical cell (PO:0030082), and rhizoid meristematic apical cell (PO:0030080) were approved at the POC meeting on 5-17-11.

Original comment by: rlwalls2008

[planteome-user]

• priority: 8 --> 1
• status: open-accepted --> closed-accepted

Original comment by: rlwalls2008

[planteome-user]

Well leaves in ferns have a lenticular apical cell, which is in the comments but not the definition. I think you need to put leaf in the definition. Also, fern gametophytes have an apical cell. That needs to be mentioned somewhere.

Original comment by: dws409

[planteome-user]

I realize it gets lost in the long list of comments, but the accepted definition (from 2011-05-03 08:08:49 EDT) for meristematic apical cell is:
A single meristematic cell at the tip of a plant structure where apical growth occurs.

Because it says "plant structure" it covers all bases. The comment then goes on to specify all of the structures in which it can occur:

Comment: Occurs in only bryophytes and some pteridophytes, at the tip of a shoot
axis apex, leaf apex, root apex, thallus apex, or protonema. This term is only used when apical growth results from division of a single meristematic cell located at the tip of an apical meristem or plant organ, rather than from a population of meristematic cells located at the tip of an apical meristem. May be tetrahedral shaped, with three (in shoots) or four (in roots) cutting faces, or wedge shaped with two cutting faces (in non-vascular leaves or thalli). An apical cell may be established upon germination of a spore or upon the first cell division of an embryo or later.

We could change wedge shaped to lenticular, or say "...wedge shaped (lenticular)..."

Original comment by: rlwalls2008

[planteome-user]

• status: closed-accepted --> open-accepted

Original comment by: rlwalls2008

[planteome-user]

• status: open-accepted --> closed-accepted

Original comment by: rlwalls2008