PLANT LEAVES

Question 1

elicits the image of foliage leaves

Answer 1

leaf

Question 2

why do leaves modify

Answer 2

− Protection
− Support
− Storage
− Nitrogen procurement

Question 3

explain physical and chemical characteristics of stem and leaves

Answer 3

− Leaves are flat and thin for maximum absorption of light and CO2. − Stems support and conduct, so a cylindrical structure is ideal.

Question 4

limitations on foliage leaves

Answer 4

− Can’t lose excessive amounts of water.
− Can’t allow entry of pathogens.
− Can’t be too nutritious and delicious to animals.
− Can’t act as a sails.
− Must be cheap.

Question 5

balancing acts between advantages and disadvantages.

Answer 5

adaptations

Question 6

The flat, light harvesting portion

Answer 6

leaf blade or lamina

Question 7

The blade’s lower side

Answer 7

dorsal / abaxial

Question 8

The upper side of the leaf

Answer 8

ventral / adaxial

Question 9

helps keep leaves from shading each other.

Answer 9

petiole

Question 10

term for leaves with no petiole

Answer 10

sessile

Question 11

term for leaves with petiole

Answer 11

petiolate

Question 12

explain monocot leaf base

Answer 12

Long and tapered monocot leaves have no petiole.

The base wraps around the stem to form a sheathing leaf base.

Question 13

difference between simple leaf and compound leaf

Answer 13

A simple leaf has a blade of just one part.

A compound leaf has a blade divided into several individual parts.

Question 14

A compound leaf has many leaflets. − Each is attached by a _____ to an extension of the petiole, the ____.

Answer 14

petiolule

rachis

Question 15

2 compound leaf types and difference

Answer 15

pinnate - all leafelets attached at the same point

palmate - leaflets attached individually along the rachis

Question 16

three guidelines to distinguish a simple leaf from a pinnately compound leaf.

Answer 16

− Leaflets never bear buds in the axils of their petiolules.
− The tip of the rachis never has a terminal bud.
− Leaflets are always arranged in two rows, never in a spiral, whorled, or decussate phyllotaxy.

Question 17

3 advantages associated with compound leaves.

Answer 17

− Leaflets can flex in the wind (or water), minimizing wind resistance and preventing tearing.
− Increased turbulence around leaflets can increase heat removal and CO2 uptake.
− Pests/disease may spread less quickly.

Question 18

leaf shapes

Answer 18

− Entire (smooth)
− Toothed
− Lobed
− Otherwise modified

Question 19

what are veins of leaves composed of?

Answer 19

bundles of vascular tissue

Question 20

eudicot veins vs monocot veins

Answer 20

Eudicot veins occur in a netted pattern of reticulate venation.
Monocot leaves have parallel venation.

Question 21

found at leaf base, cells here are involved in cutting off the leaf as it becomes useless

Answer 21

abscission zone

Question 22

forms after abscission when adjacent undamaged cells become corky

Answer 22

leaf scar

Question 23

water loss through the epidermis

Answer 23

transpiration

Question 24

when would transpiration become a serious problem

Answer 24

if the soil is so dry that roots cannot replace lost water.

Question 25

why is the the number of stomata much greater in the lower than in the upper epidermis?

Answer 25

− Reduce water loss (due to sunlight heating the upper leaf surface). − Prevent fungal spores from penetrating.

Question 26

Leaf stomata are frequently sunken into epidermal cavities that create a region of nonmoving air

Answer 26

stomatal crypts

Question 27

how do trichomes affect leaf biology

Answer 27

− Provide shade on the upper surface of the leaf. − Prevent rapid air movement, slowing water loss from stomata. − Make walking or chewing difficult for insects. − Glandular trichomes secrete powerful stinging compounds that deter even large animals.

Question 28

ground tissues interior to the leaf epidermis are collectively called

Answer 28

mesophyll

Question 29

mesophyll along the upper surface of most leaves

Answer 29

palisade

Question 30

mesophyll along the lower portion of the leaf

Answer 30

spongy

Question 31

where are vascular tissues found in the leaf

Answer 31

between palisade and spongy mesophyll

Question 32

which has a large midrib? monocot or eudicot

Answer 32

eudicot

Question 33

xylem is on the upperside and phloem on the lower side, t/f

Answer 33

t

Question 34

composed of fibers that are arranged around vascular bundles

Answer 34

bundle sheath

Question 35

larger veins often have a mass of supportive fibers above, below or both -

Answer 35

bundle sheath extension

Question 36

what are petioles?

Answer 36

the transition between the stem and lamina

Question 37

the epidermis of petiole contains fewer stomata and trichomes petiole mesophyll is rather like ______

Answer 37

cortex

Question 38

in many species of leaves, the petiole bears two small flaps of tissue at its base called ______

Answer 38

stipules

Question 39

thick and fleshy modified leaves that can survive in desert habitats favors water conservation mesophyll transparent so photosynthesis may occur deeper in the leaf

Answer 39

succulent leaves

Question 40

modified leaves: have sclerenchyma as a layer below the epidermis and in the bundle sheets. Their hardness makes them highly protected.

Answer 40

Sclerophyllous foliage

Question 41

small modified leaves that form a tight layer around the stem tip. − Protect dormant buds in the winter. − Have short or absent petioles. − Are often very waxy and tough, some hairy. − May have a thin, corky bark layer.

Answer 41

bud scales

Question 42

modified leaves of axillary buds. − Needle sharp projections. − They are protective and made primarily of fibers. − Lignified walls make them hard and resistant to decay

Answer 42

spines

Question 43

``` modified leaves whose cells can − Sense contact with objects. − Coil around objects and use them for support grow indefinitely do not photosynthesize ```

Answer 43

tendrils

Question 44

occur in plants that have C4 photosynthesis. − Lack palisade parenchyma and spongy mesophyll. − Have prominent bundle sheaths composed of large chlorophyllous cells. − Surrounding each sheath is a ring of mesophyll cells.

Answer 44

Leaves with Kranz anatomy

Question 45

Plants growing in habitats poor in nitrates and ammonia, evolved insect traps. − Captured insects are digested as a source of ______

Answer 45

nitrogen

Question 46

can be classified as either − Active traps that move during capture − Passive traps incapable of movement

Answer 46

trap leaves