Topics 06-08 Terms (Plant Chunk) Flashcards Preview

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Flashcards in Topics 06-08 Terms (Plant Chunk) Deck (54):
1

endodermal barrier

In roots, casparian strips block flow to the inside where xylem is located

Water/ions must enter endodermal cells to get to xylem

2

_____% of water taken up from roots lost to _______, mainly in the form of ____

90% of water is lost to evaporation, usually as water vapor

3

How turgor is maintained

Potassium ion uptake with ATP-powered ion channels

Water enters due to osmotic imbalance

Guard cells control stomata which control turgor

4

aerenchyma

loose parenchyma with
air spaces

allow oxygen transport to below-water parts

found in water lilies and others

5

flooding cons

depletes oxygen in roots

loss of active pumping at root hairs

loss of ion entry

may dry out leaves

6

lenticels

above water; allow oxygen to enter

7

pneumatophores

spongy, air-filled “knees”
from roots, emerging from
water

8

Food transport in phloem is mostly ___% dry matter and almost consisting entirely of _____

10-25% dry matter, mostly sucrose

9

How food transport happens

pressure flow hypothesis

source (place of dissolved carb production)

sink (place of usage
(primarily growing areas –
root and stem tips, fruits)
or storage)

10

Phloem loading

Carbs enter sieve tubes at source (active transport)

Companion cells provide energy

Water potential in sieve tube lowered, relative to nearby xylem

Increased turgor pressure in sieve tube pushes solution through them

11

"unloading" at a sink

Carbs leaving drop turgor pressure

Makes the flow from high water pressure at source to low pressure at sink

Most water in sink diffuse back into xylem

12

Macronutrients in plants

(7) COHNK CaMg (conk, camgie)

13

Micronutrients in plants

(8) Cl Fe Mn B Zn Cu Ni Mo ("cliffy men, beezin' sunny mo!")

14

How nitrogen is fixed for plants

Nitrogen-fixing bacteria turn N2 into NH3 (ammonia).

Ammonifying bacteria turn NH3 into NH4+.
Nitrifying bacteria turn NH4+ into NO3-.

Plants can only use nitrogen in the form of NH4+ or NO3-

Denitrifying bacteria take ions and turn it back into atmospheric N2

15

Commercial fertilizers usually include _, _, and _.

N P K

16

Disadvantages of commercial fertilizers

can be expensive

can pollute water supplies and
damage ecosystems

17

Organic fertilizer makes ______

Humus; helps hold
water and is usually less polluting of surface waters

18

Environments of carnivorous plants

sandy, acidic soils (like bogs) often have too
little nitrogen

19

Venus fly trap

brushed hair causes
electrical impulse, which causes very rapid water accumulation in the outer regions of lobes

digestive enzymes

usually eat more ants/grasshopper than flies

20

sundews

Trichomes act as glands, secreting sticky substances including digestive enzymes

Leaves curl around prey

21

butterworts

Glands on leaves secrete sticky
substances and
digestive enzymes

Leaves curl around prey, mostly gnats

22

pitcher plants

Insects can't climb back out

Some have digestive enzymes, some digest using other organisms through mutualism

23

Bladderworts

traps in aqueous environments

bladderlike leaves that have a spring-like trapdoor

digestive enzymes

24

mycorrhizae

90% of vascular plants have relationships between their roots and these certain fungi

important mostly for phosphorous and micronutrients

25

Plant development characteristics

Cells do not change positions during development

Growing tips and zones (meristems); regeneration capacity

No fixed body size, flexibility and adaptability

Adaptive development influenced by environment

26

Fungi and animal development

Fungi grow with little specialization, except for reproduction

Animal development is usually complex but relatively inflexible

27

suspensor

larger cell in the first division of a seed embryo

links embryo to nutrient tissue in seed

28

root-shoot axis

Near suspensor = future root

Other end = future shoot

29

mature seed embryo characteristics

Root-shoot axis

Cotyledons growing out of shoot

Plumule; may have a coleoptile (protective sheath)

30

Where food is stored in a seed

Endosperm or cotyledons

31

____% of seeds are water

5-20% water

32

Food reserves in seeds are mostly ________

starch grains in amyloplasts, protein bodies, sometimes fat bodies

33

First step in seedling growth

roots emerge first (usually)

34

Plant hormones control _______

gene expression

35

Auxin

Elongates cells, and is transported away from areas in the light

Usually found in apical meristems or other immature areas

plasticity of cell walls

bending of stems, stem elongation

inhibits leaf abscission

promotes lateral bud dormancy

36

Cytokinins

Natural ones similar to adenine

Usually produced in root apical meristems and developing fruits

cell differentiation

works with auxin to stimulate cell division

promote lateral buds, inhibit lateral root growth

promote chloroplast development/maintenance

37

Gibberellins

Activate production of food utilization enzymes

Made in apical parts of stems and roots

shoot elongation, hastened seed germination

38

Brassinosteroids

Overlapping functions with auxins and gibberellins

Found in pollen, immature seeds, shoots, and leaves

39

Oligosaccharins

Pathogen defense (possible reproductive development)

Found in cell walls

40

Ethylene

Promote some defense responses to environmental stress

Formed around lateral buds stimulated by auxin, in pollinated flowers, developing fruits

lows stem and root growth

hastens fruit ripening

increase in respiration in
fruits

allows abscission at fruit peduncles and leaf
petioles

41

Abscisic acid

Seed dormancy

Affects stomata opening and closing

Made in mature green leaves, fruits, root caps

produces a yellow area when applied to a green area

very rapid effects; not likely to be due to changes in gene expression



42

salicyclic acid

Plant defense responses against pathogens

43

apical dominance depends on combined effects of ____, _____, ______

auxin, cytokinins, ethylene

44

final plant form typically determined by a balance of ______ and ______

auxin and cytokinins

45

tropism

growth responses to external stimuli (irreversible growth)

46

phototropism

Stem systems grow toward light (auxin often involved)

47

gravitropism

Stems grow up, roots grow down

48

thigmotropism

Response to contact; examples are tendrils, venus flytrap closing

49

turgor movements

Reversible changes in turgor pressure

Involves active ion import/export, water influx/efflux to relieve osmotic imbalance

Examples are opening/closing stomata, "opening/closing" leaves and flowers

50

photoperiodism

response to a length of DARK period

51

long-day plants

Flower only when the day length is over 12-16 hours

52

short-day plants

AKA "long night" plants

Flower only when day length is shorter than 14 hours

53

Color light most effective in stopping flowering

Red light

54

phytochrome

A blue pigment with two states (Pr and Pfr) involved in flowering

Affects etiolation

Pfr is biologically active, Pr is not

Pfr becomes Pr over time in the dark