Lab 2 Flashcards
protomeristem
a group of young meristematic cells in its early embryonic stage present at the shoot and root tip of a plant from which the other meristems are derived
primordium
is an organ or tissue in its earliest recognizable stage of development, cells of the primordium are called primordial cells, from them the organ/tissue develops
bud
plant structure present on the stem containing undeveloped tissue that can produce new stems and leaves,
there are lateral - responsible for development of lateral organs and apical buds - responsible for elongation
lateral bud/axillary bud
buds along the sides of a stem that give rise to new shoots, either vegetative - branches and stems or generative - flowers
apical bud
bud located at the tip of the stem or the branch, which is responsible for elongation
organogenetic zone
pools of dividing cells that reside in the meristems, they are responsible for creation and growth of the organs
stem
vascular plant organ consisting of an alternating system of nodes and internodes that support the leaves and reproductive structures,
it creates a connection between all plant organs and takes part in transport of water, minerals, metabolic products etc
shoot
plant shoot consists of any plant stem together with its appendages like leaves, lateral buds, flowering stems, and flower buds
epidermis
outermost layer of the stem
covered by cuticle - pathogen protection and limiting water loss
secondary, unevenly thickened, cutinized cell wall
colourless plastids (leucoplasts often)
large vacuole, anthocyanins
primary cortex
made of collenchyma, parenchyma
starch sheath in dicots
serves the function of a gravitropic sensor
starch sheath cells differentiate further and they can form Casparian strip and other ultrastructural traits typical of root endodermis
chlorenchyma
type of parenchymatous tissue that contains chlorophyll, assists plants in performing their photosynthetic function, can be found below the epidermis
angular collenchyma
collenchyma in which cells have thicker cell walls at the ends, giving them an angular appearance, can be found in primary cortex
lamellar collenchyma
collenchyma in which cells have continuous layers of thickening in their cell walls, the thickenings are in the outer and inner tangential walls, can be found in primary cortex
ground parenchyma
a versatile ground tissue that generally constitutes the “filler” tissue in soft parts of plants, forms the cortex and pith of stems, the cortex of roots, the mesophyll of leaves, the pulp of fruits, and the endosperm of seeds
druse
a rounded cluster of calcium oxalate crystals found in some plant cells, defense against herbivory
idioblast
isolated plant cell of a different type surrounded by cells homogeneous to themselves, for example tannin cells, mucilaginous cells, secretory cells in ground parenchyma of stele
starch sheath
in dicot stems
close to SAM, where primary structure is initiated
in older parts of stem, the starch sheath no longer serves as gravitropic sensor
starch sheath cells differentiate further and they can form Casparian strip and other ultrastructural traits typical of root endodermis
stele
consists of pericycle, vascular tissue , ground parenchyma containing:
idioblast with druse (tannin cells, mucilaginous cells, secretory cells)
fiber/stereid
a ground tissue cell with thickened cell walls, functions in support rather than conduction, may or may not retain a living protoplast at maturity
pericycle
the outermost, unicellular layer of the vascular cylinder of a stem, transports water and nutrients between vascular bundles and primary cortex
procambium
primary tissue of roots and shoots that forms the vascular tissue
cambium
a cellular plant tissue from which phloem, xylem, or cork grows by division, resulting in secondary thickening
collateral open vascular bundle
collateral = pr phloem and pr xylem opposite, radical arrangement
open = fascicular cambium present
collateral closed vascular bundle
collateral = pr phloem and pr xylem opposite, radical arrangement
open = xylem and phloem are arranged side by side in the same radius which are not separated by the cambium
sieve tube
cell belonging to phloem,
made of:
- simplified protoplast (nucleus, ribosomes, tonoplast, Golgi apparatus absent)
- ER, plastids and mitochondria simplified
- P protein
- non lignified cell wall
the transverse walls are transformed into sieve plates
sieve tube member
a sieve element of a type present in angiosperms, a series of which are joined end to end to form sieve tubes, with sieve plates between the elements
sieve plate
result of transverse walls transformation in sieve cells
callose
a polysaccharide in the form of β-1,3-glucan with some β-1,6-branches and it exists in the cell walls and plays important roles during a variety of processes in plant development and/or in response to multiple biotic and abiotic stresses
companion cell
supports support long distance transport
in angiosperm, in gymnosperm as albuminous cells
low vacuolation of protoplast
numerous: active mitochondria, RER and ribosomes
large plastids
transfer cell role
phloem parenchyma
storage
auxiliary functions in short distance transport
in angio and gymnosperms
transfer cell role: parenchymatous cell specialised in active transport of substances across plasma membrane
phloem fibers
mechanical strength and support
in angio and gymnosperms
tracheid
part of xylem, a long and tapered lignified cell in the xylem of vascular plants
lignified secondary cell wall
support + water transport
bordered pits providing water movement between adjacent cells
vessel
part of xylem,
shorter, thicker
perforation plates
more efficient than tracheids
ferns, gymnosperm and angiosperm plants
vessel member
the principal water-conducting cells in angiosperms and are characterized by areas that lack both primary and secondary cell walls, known as perforations
perforation plate
an area or areas in which there is no shared wall material or membrane in vessels
xylem parenchyma
has a cell walls thickened with pits of various types
storage and mediating exchange between tracheal elements and other cells
they divide into axis and ray (along radial axis of stem) orientation
xylem fiber
made up of dead sclerenchyma cells in between the xylem vessels and tracheids of the xylem tissue, and chiefly provide mechanical support
ray
the radial component of the secondary plant body,
formed near the pith from the interfascicular parenchyma, connecting the pith with the cortex, are termed medullary rays; all other rays originate from the cambium
pith
a tissue in the stems of vascular plants
composed of soft, spongy parenchyma cells, which in some cases can store starch
air canal
aerenchyma formed gaps in stem allowing gases to flow between the shoot and the ground
vine/liana
plants with long, flexible, climbing stems that are rooted in the ground, and usually have long dangling branches
