Plant body

Question 1

define growth

Answer 1

irreversible increase in size as a result of cell division and cell enlargement

Question 2

define differentiation

Answer 2

The process through which cells with identical genetic background become different from one another and acquire different functions

Question 3

what is the vegatative body of a plant?

Answer 3

The above ground section (leaves, stem) and the underground section (roots)

Question 4

what is the name for the repeating modules of plants?

Answer 4

Phytomeres

Question 5

give an example of different phytomers

Answer 5

internode, node, leaf, auxillary bud

Question 6

what are the three types of tissue that make up a plant body?

Answer 6

dermal, ground, vascular

Question 7

when are the three plant tissues formed?

Answer 7

During embryo development

Question 8

what is the basic pattern of plant tissue in all plants?

Answer 8

Dermal - outside
Ground - next layer
vascular - inner most layer

Question 9

what are the features of dermal tissue?

Answer 9

mostly unspecialised cells - free of chloroplasts

Question 10

what are the functions of dermal tissue?

Answer 10

mechanical protection, minimises water loss, selective absorption
- guard cells, trichomes, root hairs

Question 11

what are the three types of ground tissue?

Answer 11

pernchyma cells, collenchyma cells, sclerenchyma cells

Question 12

what are parenchyma cells?

Answer 12

continous masses of cells in the pith of stems in leaves, flesh of fruits

Question 13

what are collenchyma cells?

Answer 13

mechanical support in growing organs. Thick cell walls. Often close to the epidermis e.g. strings of celery stalks

Question 14

what are sclerenchyma cells?

Answer 14

thick, lignifided cell walls: strength and support

Question 15

what is vascular tissue?

Answer 15

Xylem and Phloem - continous system extending through the body transporting water and solutes and conduit signals

Question 16

when is the plant body established?

Answer 16

in the embryo

Question 17

what occurs in early seed development?

Answer 17

• apical-basal polarity
• radial polarity
• tissue specification
• basic organ formation

Question 18

in addition to the three main plant tissues what two things do we also see in a plant embryo?

Answer 18

Radicle - embryonic root
Cotyledons - embryonic leaves

Question 19

Plants are sessile, how does this effect growth?

Answer 19

they need to adjust the number and size of organs throughout their life cycle

Question 20

what are the two mechanisms facilitating plant growth?

Answer 20

cell division and cell enlargement

Question 21

where does cell division take place in plants and what is it?

Answer 21

At meristems - populations of undifferentiated, self renewing, actively dividing stem cells

Question 22

what is cell expansion?

Answer 22

Enlargement due to uptake of water into the cell

Question 23

what are meristems?

Answer 23

populations of undifferentiated, self-renewing and activley dividing stem cells

Question 24

when are meristems formed?

Answer 24

during embryonogensis

Question 25

what are the two primary meristems?

Answer 25

- the shoot apical meristem (SAM) - the root apical meristem (RAM)

Question 26

what are the primary meristems responsible for?

Answer 26

the polarity of growth along the primary plant axis

Question 27

what other meristems are there in addition to primary meristems?

Answer 27

lateral meristems

Question 28

what are lateral meristems responsible for?

Answer 28

responsible for secondary growth

Question 29

The axillary buds on the stem that give rise to branches are example of what type of meristem?

Answer 29

Lateral

Question 30

what does the root apical meristem give rise to?

Answer 30

all below ground plant organs

Question 31

What are the 4 developmental zones of the root tip?

Answer 31

root cap, meristematic zone, elongation zone, maturation zone

Question 32

give the features of the root cap

Answer 32

most distal part of the plant covering the meristem, allowing protection from mechanical injury and perception of gravity (geotropism)

Question 33

give the features of the meristematic zone

Answer 33

RAM - initialises all of the other cell types in the root and allows polarised cell divisions produce cells of the three basic tissues: these divide further before they differentiate

Question 34

give the features of the elongation zone

Answer 34

- growth through rapid and extensive cell elongation - rate of cell divisions progressively reduced - end of EZ: cells reach their final size

Question 35

give the features of the maturation zone

Answer 35

- cell divisions ceased - cells start to differentiate - formation of lateral organs - root hairs: increased root surface; uptake of water, minerals, ect - lateral roots: complete root system

Question 36

along the root axis how are cells arranged?

Answer 36

arranged in files with sucessive stages of differentiation and in concentric circles

Question 37

what is the dermal tissue in a root tip?

Answer 37

- non hair cells - root hair cells

Question 38

what are the ground tissues in