POC Conf. Call 4-28-11

POC meeting, Webex Conference Call; Date: Thursday April 28th, 2011 10am (PDT)

In attendance:

POC members:

Absent:

Collaborators:

Acceptance of the minutes from the POC_Conf._Call_4-26-11?

New terms for Physcomitrella and related taxa (continued)

Conductive cells and tissue

• axial cell

We need to address the definition of axial cell, as it was written with angiosperms in mind.

axial cell (PO:0000081): A vascular cell derived from the fusiform cambial initial and oriented with its longest diameter parallel with the main axis of stem or root. [source: ISBN:0471245208]

Comment: These cells make up the axial system, also known as vertical or longitudinal system.

The term vascular cell does not exist in the PO, and should be removed from the definition, so it can encompass hydroids and leptoids. Also, current definition does not encompass conductive cells in leaves that do not arise from cambium.

Currently has develops_from fusiform initial, which is_a cambium initial, which is part_of vascular cambium, which is part_of vascular system. This won't work for hydroids and leptoids.

Proposed def.: A plant cell that develops from a fusiform cambial initial and is oriented with its longest diameter parallel with the main axis of a plant axis.

Conductive cell types for bryophytes

• hyrdoid (PO:0025032):: An elongate, water conducting cell that is dead at maturity, with tapered ends that are thin and partially hydrolyzed, that lacks specialized wall thickenings or lignin. [source: ISBN:0962073342 (Crum), ISBN:9780717810073]

Comment: Occurs in the gametophytic phase of a plant life cycle.

Proposed def.: An axial cell that is dead at maturity, with tapered ends that are thin and partially hydrolyzed, and lacking specialized wall thickenings or lignin.

Comment: Water conducting cells found in bryophytes, mainly in the gametophytic phase, but also sometimes in the sporophytic phase.

part_of hydrome

• leptoid (PO:0025033): A food conducting cell associated with hydroids that resembles the sieve elements of some seedless vascular plants. [source: ISBN:962073342, ISBN:9780717810073]

Comment: Occurs in the gametophytic phase of a plant life cycle.

Proposed def.: An axial cell that resembles the sieve elements of some seedless vascular plants.

Comment: A food conducting cell found mainly in the gametophytic phase, but also sometimes in the sporophytic phase, of bryopytes.

part_of leptome

conductive tissue for bryophytes

midrib/costa

Moss Ontology definition: The nerve of a phyllid. Altered from Bill and Nancy Malcolm (2006)

We have term midvein (PO:0020139): The central, and usually the most prominent, vein of a leaf or leaf-like organ. [source: APWeb:Glossary] (which, by the way, should just say phyllome, instead of leaf or leaf-like organ). However, midvein is_a leaf vein, which is a portion of vascular tissue, so it cannot apply to mosses.

We should have a term that groups conductive tissue together for both vascular and non-vascular plants, kind of like we have axial cell for vascular and non-vascular conductive cells.

New child of portion of plant tissue: portion of axial tissue:

(also, we need to redefine phloem to be more like definition of xylem, and not based on function) (need to redefine axial cell so it doesn't say vascular cell)

These terms were not proposed by the Physco group, but should be in the PO.

• hydrome

• leptome

Sporangium parts

This is continued from our discussion at the POC_Conf._Call_3-8-11

Currently classes like exothecium, endothecium, primary parietal cell layer and tapetum are part of anther wall (PO:0000002). However, these layers and their constituent cell types can be part of any sporangium, not just an anther. Proposed making them part of a general class sporangium wall (as we did for parts of leaf).

See Summary of sporangium development