lab 3 terms Flashcards
embryo axis
the part of the embryo within a seed which will develop into the plant; all parts of the embryo except the cotyledon(s)
epicotyl (plumule)
the upper portion of the embryo axis; produces the shoot system
foliage leaves
part of the epicotyl within a seed; the small leaves which surround SAM
hilum
scar on the seed coat of some seeds (e.g. beans) that marks the former attachment point of the funiculus
hypocotyl
part of the embryo axis or seedling located between the cotyledons and the radicle (not present in monocots)
hypocotyl hook
a bending of the hypocotyl during emergence of a germinating bean seed; function is to pull the cotyledons and epicotyl above the soil while protecting SAM from abrasion with the soil
radicle
the lower portion of the embryo axis which will develop into the primary root
primary growth
growth originating from the SAM and RAM of the stems and roots; primarily increases the length of the plant
primary meristem
a temporary meristem produced by SAM and RAM which will continue to divide for a short time near the growing shoot and root tips; three are produced, once for each tissue system: the protoderm, ground meristem, and the procambium
tunica
the outermost layer(s) of SAM; undergoes surface growth by anticlinal cell divisions
corpus
the interior layers of SAM; undergoes volume growth by cell division in all planes
protoderm
a primary meristem produced by SAM and RAM; formed as the outermost single cell layer; its cells will divide rapidly for a short time and then mature into cells of the dermal tissue system
procambium
a primary meristem produced by SAM and RAM; formed as strands wherever a vascular bundle or midrib will develop; its cells will divide rapidly for a short time and then mature into cells of the vascular tissue system
ground meristem
a primary meristem produced by SAM and RAM; formed within the rest of the plant body besides the dermal and vascular tissue (cortex, pith, and mesophyll); its cells will divide rapidly for a short time and then mature into cells of the ground tissue system
leaf primordium
youngest, tiny leaves produced by SAM and lying next to SAM
secondary growth
growth originating from lateral (secondary) meristems (vascular cambium and/or cork cambium) of the stems and roots; primarily increases the width of the stem or root
secondary (lateral) meristem
a thin, cylindrical layer of meristematic cells within a stem or root which divide both to the inside and outside to produce rings of secondary tissues
secondary xylem
a secondary vascular tissue; xylem tissue produced by the vascular cambium; forms the wood of a stem or root in annual rings rather than discrete bundles to the inside of the vascular cambium
secondary phloem
a secondary vascular tissue; phloem tissue produced by the vascular cambium; forms a ring rathe than discrete bundles to the outside of the vascular cambium
primary xylem
xylem tissue produced by the procambium as part of primary growth
primary phloem
phloem tissue produced by the procambium as part of primary growth
annual (growth) ring
a layer of secondary xylem laid down within one growing season by a woody plant
resin duct
a canal lined with secretory cells found within the mesophyll, cortex, and secondary xylem of conifers such as pine; contains resin
vascular ray
a band of parenchyma cells, produced by the vascular cambium, which crosses through the secondary phloem, vascular cambium, and secondary xylem; provides lateral transport across the stem, primarily to move water from the secondary xylem to the living cells of the secondary phloem and periderm
periderm
protective secondary dermal tissue which replaces the epidermis when it is destroyed by secondary growth; consists of the phellogen, phelloderm, and phellem
cork cambium (phellogen)
a lateral meristem (a cylindrical sheath of meristematic cells) which divides to form secondary dermal tissue (periderm) which consists of parenchyma (phelloderm) and cork cells (phellem)
cork cells (phellem)
a secondary dermal tissue, the outermost layer of the periderm, produced by the cork cambium (phellogen) to the outside of the cork cambium; dead at maturity with suberin-impregnated cell walls
phelloderm
a secondary dermal tissue, the innermost layer of the periderm, produced by the cork cambium (phellogen) to the inside of the cork cambium; usually parenchyma
suberin
fatty material located within the cell walls of cork cells and the Casparian strip of endodermal cells
bark
all tissues outside of the vascular cambium in a woody stem
