Lecture 13: Plant Development

Question 1

what have plants ever done for us?

Answer 1

• cotton
• pills
• food
• oxygen

Question 2

food, energy and water shortages are fuelled by

Answer 2

growing populations

Question 3

plants aid earth how?

Answer 3

• use light as a sustainable energy source
• run on CO2 and produce oxygen
• require modest capital, start-up & maintenance, easily scalable
• produce wide range of useful products
• pleasing landscape

Question 4

key stages of development in animals

Answer 4

• fertilisation (fusion of egg and sperm to give zygote)
• cleavage (division of cells to form blastula)
• gastrulation (formation of tissue layers & axis)
• organogenesis (formation of organs)
• Morphogenesis (mechanism of body shape formation)

Question 5

plant cells are fused together by a

Answer 5

cell wall

Question 6

the 3D form of a plant depends on the

Answer 6

previous number and orientations of cell division and the relative growth of the cells

Question 7

the orientation of cell division and the relative growth of cells defines

Answer 7

both the overall form of the plant and the internal anatomy

Question 8

how are plants like animals

Answer 8

• develop from a fertilised egg
• the zygote undergoes growth and division to form multi-cellular organism
• plant cells differentiate to take on specific function s

Question 9

how are plants NOT like animals

Answer 9

-consist of cells are encased in a wall. They are immobile. Size and shape of the organism is determined by patterns of cell division and growth
-show extensive post-embryonic generation of form.
This is due to the maintenance of stem cell niches (meristems)

Question 10

the adult forms of plants and animals consist of

Answer 10

repeated elements

Question 11

in plants the repeated elements that form it are

Answer 11

not set down in the embryo, they’re formed by the shoot apical meristem

Question 12

the meristem is

Answer 12

a highly dynamic structure generating form and pattern

Question 13

_____ signals control positioning in the body

Answer 13

CHEMICAL

• Cells “know” they are in an organism by interpreting POSITIONAL INFORMATION
• positional inför

Question 14

Positional information is given by___ what in plant so cell know where they are in an organism

Answer 14

given by the concentration of a MORPHOGEN

FRENCH FLAG MODEL

Question 15

___ plays key role in many patterning processes in plants

Answer 15

AUXIN

Question 16

Polar Auxin Transport (PAT )

Answer 16

• auxins are week acids. inside the cell is negative (IAA-)
• PIN protein (auxin export) leave & are protonated so = IAAH
• AUX1 (auxin import) IAAH enters and deprotonated to IAA- again

-one direction of movement

Question 17

the pattern of auxin flux in the shoot meristem dictates where

Answer 17

leaf formation occurs

Question 18

computation models of auxin transport mimic

Answer 18

natural patterns

Question 19

three primary meristems in the roots are:

Answer 19

protoderm
ground meristem
procambium

Question 20

description of root structure

Answer 20

bottom:

• Root cap
• quiescent center
• apical meristem surround quiescent centre
• zone of elongation
• zone of maturation with root hair.
• stele (middle)
• cortex
• epidermis

Question 21

pattern of auxin flow is determined by

Answer 21

PIN transportes in the root leads to a local high auxin level which determines where the root stems cells form

Question 22

the primary meristems define

Answer 22

the basic structure of the plant

Question 23

plants vs animals in young and adult growth forms

Answer 23

• the mature plant form is vastly more complicated than the embryo
• i plants growth and development can occur over long time spans

Question 24

plant development depend on the distribution of

Answer 24

secondary meristems (stem cell niches) throughout the plant

Question 25

where are secondary meristems generated?

and what do 2nd meristems become?

Answer 25

primary apical meristem. Secondary meristems can be activated to form new structures, linking environment to form (distance from animals)

Question 26

distribution of meristems throughout the plant enable it to

Answer 26

withstand & respond to serious damage

Question 27

pattern of meristem activation determines

Answer 27

form. Plants develop geometric form by branching

Question 28

meristems within the stem can become activated to

Answer 28

increase stem size (“cambium” meristems)

Question 29

wood formation depends on

Answer 29

meristems.
2 types
–vascular cambium (inside)
–cork cambium (outside)

Question 30

root contains numerous meristems:

Answer 30

• Pericycle (site of secondary meristems) [above root tip]

- primary meristem (closer to bottom)

Question 31

the pericycle generates

Answer 31

new lateral roots which allow the plant to explore its environment. Activation of the pericycle links development to the environment

Question 32

meristems can be cultures to..

Answer 32

…multiply & regenerate whole plants

Question 33

transcription factors involved in meristem function can be used to

Answer 33

manipulate plant form

Question 34

kalanchoe generates…

Answer 34

ectopic meristems along the edge of the leaf. Each meristem forms a bud which can generate a plant (asexual reproduction )

Question 35

meristems contain…

Answer 35

the stem cells for the plant & produce cells from which the rest of the plant is made

Question 36

meristems are distributed in one place in plants T/F

Answer 36

FALSE

Question 37

activation of meristems can breath influence the final plant form T/F

Answer 37

TRUE

activation is often dependant on environmental triggers

Question 38

molecular biology has led to the identification of genes required for meristem function T/F?

Answer 38

TRUE