POLARITY OF PLANT DEVELOPMENT Flashcards

1
Q

plant dvevelopment diagram: (8)

A

1-cell
4-cell
octant
dermatogen
early globular
late globular
transition
late heart

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2
Q

Construction of the Arabidopsis Body Plan During Embryogenesis (8)

A
  1. Polarity Establishment
  2. Asymmetric Division
  3. Early Development
  4. Dermatogen Stage
  5. Globular Stage
  6. Heart Stage
  7. Torpedo Stage
  8. Quiescent Stage
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3
Q

Construction of the Arabidopsis Body Plan During Embryogenesis :

  1. Polarity Establishment

Post-fertilization, the Arabidopsis zygote exhibits polarity, characterized by a cytoplasmically dense _____ and more vacuoles at the _____.

  1. Asymmetric Division

the apical cell _____
the basal cell _____

A
  1. apical end
    basal end
  2. embryo
    suspensor cells
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4
Q

Construction of the Arabidopsis Body Plan During Embryogenesis :

  1. Early Development
    The embryo progresses through symmetric divisions forming a ____ structure of 2, 4, and 8 cells.
    The suspensor continues to divide longitudinally.
  2. Dermatogen Stage
    Formation of the ____ (forms epidermis) from a single outer layer of cells through transverse divisions.
A
  1. radial

4.protoderm

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5
Q

Construction of the Arabidopsis Body Plan During Embryogenesis :

  1. Globular Stage
    radial divisions give rise to ____ within embryo

lens shaped cell of the upper suspensor cell gives rise to ___ of the root apex

  1. Heart Stage
    Proliferation of cells in the upper half gives rise to _____
A
  1. central vascular initials
    central cells
  2. cotyledon primordia
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6
Q

Construction of the Arabidopsis Body Plan During Embryogenesis :

  1. Torpedo Stage
    torpedo stage embryo further elaboration of the root and shoot apices and growth of ____
  2. Quiescent Stage
    embryo now has ____ cells and 0.5 mm in length

To activate it needs ___ and ___

A
  1. cotyledon
  2. 20,000 cells
    dispersal
    germination
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7
Q

Challenges of Embryogenesis (3)

A
  1. Body Plan Establishment
  2. Meristematic Tissue Reservation
  3. Food Reserve Establishment
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8
Q

Challenges of Embryogenesis:

  1. Body Plan Establishment:
    Radial patterning produces ____

Axial patterning establishes the ____

  1. Tissue Reservation:
    Setting aside ____ tissue for postembryonic growth (leaves, roots, flowers).

Food Reserve Establishment:
Creating accessible food reserves for the germinating embryo until it becomes _____.

A
  1. three tissue systems
    apical-basal (shoot-root) axis.
  2. meristematic
  3. autotrophic
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9
Q

Polarity Establishment:
Polarity in plants is established in the _____ The polarity of the embryo defines an axis upon which the body plan of the plant is elaborated

The ____ was shown to be a source of
position-dependent information required
for polarization in the Fucus zygote

A

first cell division post-fertilization

cell wall

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10
Q

Characteristics common to both angiosperm and brown algae:

Daughter cells stay connected after mitosis.

Cells are embedded in a rigid ____ made of cellulose fibrils.

Cells maintain cytoplasmic continuity through _____.

Both exhibit open growth strategies with continuous production of new organs from _____.

Some lineages have meristems capable of three-dimensional division, establishing secondary cytoplasmic continuity.

Multicellular development relies on ____ rather than clear cell lineages.

_____, the ability to dedifferentiate upon isolation, is common.

A

extracellular matrix

plasmodesmata

meristematic cells

positional control

Totipotency

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11
Q

Adult plant growth is due to the activity of _____ established during embryogenesis. Organised cellular structures capable of indeterminate growth contains an organised core of undifferentiated “____”

A

meristems

stem cells

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12
Q

Classification of meristem (3):

Origin
1. initial formative tissue from which other meristems are derived.
2. responsible for the primary growth of the plant.
3.Develops from permanent tissues

Location
1. tips of roots and shoots, responsible for lengthening the plant.
2.between mature tissues, often in grasses, aiding in regrowth of parts removed by grazing.
3. sides of stems and roots, responsible for thickening

Plane of Division
1. Cells divide in multiple planes.
2.Cells divide in two planes, like epidermal layers
3. Cells divide in one plane, leading to increased length of organs.

A

Origin
1. Promeristem
2. Primary meristem
3. Secondary meristem

Location:
1. Apical meristem
2. Intercalary meristem
3. Lateral meristem

Plane of Division:
1. Mass meristem
2. Plate meristem
3. Rib meristem

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13
Q

Planes of Cell Cleavage:

_____ are the ones that occur parallel to the tissue or organ surface resulting to rows of cells stacked one over the other “=”

______ is cleavage at right angles to the tissue or organ surface resulting to columns of cells adjacent to one another “ ||”

A

Periclinal cell divisions:

Anticlinal cell divisions:

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14
Q

DOMAINS OF GROWTH AND DEVELOPMENT

____ - straight line about which a body or a geometric figure rotates

_____establishes the apicalbasal (shoot-root) axis, embryonal axis divides the embryo or immature plant into regions by the help of embryonal
axis region.

____ are functional repetitive units of a plant, continually produced by root and shoot meristems throughout a plant’s vegetative life-cycle

A

Plant axis

Axial patterning

Phytomers

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15
Q

DOMAINS OF GROWTH AND DEVELOPMENT

(5)

(3)

A

Phytomer
Growth Unit
Axis
Architectural unit
Whole plant

Growth
Branching
Reiteration

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16
Q

Axial domain of growth:

_____- means forming the center
_____- means away from the center
_____ - facing away from the axis of an organism
_____ - facing toward the axis of an organism

A

Central
Peripheral
Abaxial
Adaxial

17
Q

Axial domain of growth:

___ = _____

= _____

A

saggital plane
coronal plane

18
Q

The ____ is essential for radial growth. Thickening of vascular plants is regulated by stem cell-like tissues, including the vascular and the _____ organized in concentric cylinders

A

vascular cambium
cork cambium

19
Q

Radial growth (5)

A

vascular cambium cell
new secondary xylem cell
new secondary phloem cell
new secondary xylem cell
new secondary phloem cell

20
Q

Maturity and polarity:

acropetal growth had greater _______ (i.e., mitotic activity) near the tip and a gradient of maturation toward the base

A

cell proliferation

21
Q

EMBRYONIC CELL FATE

Cell fate determination is governed by (2)

A

(1) its parent cell (i.e. the cell’s lineage)
(2) the position of the cell within the embryo

22
Q

____ regulates cell fate by influencing gene expression through its signaling pathways. It interacts with_____and other signaling molecules to turn genes on or off, leading to the activation or repression of growth factors and developmental genes.

The unique transport mechanism of auxin, involving _____ that direct its movement from cell to cell, creates the gradients that are so essential for its signaling role.

A

Auxin
transcription factors

efflux carriers

23
Q

The apical cell and its daughters adopt an isometric growth pattern and divide twice longitudinally and once transversely to form a spherical ____ of eight cells.

The uppermost daughter of the basal cell, termed ____, eventually becomes part of the primary root meristem, whereas the remaining daughters form the extraembryonic suspensor.

A

proembryo

hypophysis

24
Q

Development of Embryonic Shoot / (Shoot Apical Meristem (SAM) Organization)

Zones of the SAM (3):
This is the topmost region of the SAM, where cells are primarily undifferentiated and are actively dividing responsible for maintaining the stem cell population.

Surrounding the prior, cells start to differentiate and contribute to the formation of new organs such as leaves.

Located beneath , the rib zone contributes cells to the stem and internodes as the plant grows vertically.

A

Central Zone (CZ)

Peripheral zone (PZ)

Rib Zone (RZ)

25
Q

Layers of the SAM:
Layer 1 (L1): The outermost layer, which predominantly divides anticlinally (perpendicular to the surface of the meristem). Cells in this layer give rise to the____ of the plant.

Layer 2 (L2): Located just below L1, this layer also divides primarily anticlinally. L2 contributes cells that will become part of the _____.

Layer 3 (L3): The innermost layer of the SAM, which divides in multiple directions. Cells from this layer differentiate into various ____of the plant.

A

epidermis

internal tissue

internal tissues

26
Q

Role of Hormones:

_____ Crucial for the initiation and regulation of organ patterning at the shoot apex. It is dynamically distributed within the SAM, creating ____ that signal where new organs should form.

_____Promotes cellular division and works in contrast to the other hormone by promoting cell division in the meristem’s central zone.

A

Auxin
local maxima

Cytokinin

27
Q

Development of Embryonic Root

The uppermost daughter of the basal cell, known as the ____, becomes part of the primary root meristem. This cell is crucial for the establishment of the root apical meristem (RAM).

_____ serves as the growing point of the root, containing stem cells that will produce all the cells of the primary root. It is characterized by _____ slow dividing to regulate the division of surrounding meristematic cells.

A

hypophysis

Root Apical Meristem (RAM)

quiescent center (QC)

28
Q

Layer Differentiation in the RAM:

Organization of the RAM:

The RAM consists of several distinct cell layers, each with specific roles in root development:

_____ which is a region of slowly dividing cells that help regulate the division of surrounding meristematic cells.

_____ The bottom-most layer, consisting of cells that directly perceive gravity, aiding in directing root growth downward. (D1=stem cells; D2-D4= differentiated layer)

A

Quiescent center (QC)

Columella

29
Q

Initial cells: (cells within the boundary)

_____ The outer layer, which protects the root and facilitates absorption of water and nutrients.

_____Surrounds the vascular tissue, involved in storage and transport of nutrients.

_____ The innermost cortical layer that regulates the flow of water and solutes into the vascular tissue.

A

Epidermis (EP)

Cortex (C):

Endodermis (EN):

30
Q

Focus of Root Development (3)

(organogenesis, lateral roots)
(zone of cell expansion)
(tip of the root, “stem cells”)

A

Root branching
Tissue patterning
RAM maintenance

31
Q

Bryophyte development (3)

_____Thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase) in the life cycle of mosses

_____ are elongated cylindrical shaped cells that form during the development of the moss protonema

_____ are longer and narrower than chloronemal
cells, derived from cells at the tips of filaments

A

Protonema

Chloronema

caulonema

32
Q

Conifers are what?

A

Polyembryogenic

33
Q

The fundamental difference between nonvascular and vascular plant embryogenesis is polarity:

Sporophyte of nonvascular plants grows ____

Sporophyte of vascular plants grows _____

A

exogenously

endoscopically

34
Q

Types of endosperm development (3)

____ involves the formation of a multinucleate syncytium from the primary endosperm nucleus followed by cellularization.

_____ eatures the early formation of individual cells through cytokinesis after division of the primary endosperm nucleus.

_____ arly partitioning of the endosperm into cellularized and non-cellularized regions within the syncytium

A

nuclear cellular helobial

35
Q

Embryo occur through fertilization, Endosperm occur through ____

Endosperm formed through ___ and ____ which thne provides nutrients to the embryo

A

triple fusion

binucleate central cell
sperm cell

36
Q

____ development of fruit without fertilization

____ without sexual reproduction, makes a seed that germinates into a maternal clone

A

Parthenocarpy

Apomixis