Plant Physio

Question 1

absorb water and minerals (nutrients)
from the soil

Answer 1

roots

Question 2

The most important nutrients plants need
include:

Answer 2

nitrogen, phosphorus,
potassium, magnesium, and calcium

Question 3

A plant cannot extract all the water in the soil because some of it is
tightly held by hydrophilic soil particles.

Answer 3

Soil water

Question 4

Clay in soil prevents the ________________ during
heavy rain or irrigation because of its large surface area for binding minerals.

Answer 4

leaching (drain away) of mineral nutrients

Question 5

_______ charged minerals such as potassium (K+),
calcium (Ca2+), and magnesium (Mg2+), adhere by electrical attraction to the ______ charged surfaces of clay particles.

Answer 5

Positively; negatively

Question 6

Minerals that are _____ charged, such as nitrate
(NO3−), phosphate (H2PO4−), and sulfate (SO42−), are less tightly bound to soil particles and tend to leach away
more quickly.

Answer 6

negatively

Question 7

_______ charged mineral ions are made available to the plant when hydrogen ions (H+) in the soil displace the mineral ions from the clay particles.

Answer 7

Positively

Question 8

is stimulated by the roots, which secrete H+ and compounds that form acids in the soil solution.

Answer 8

cation exchange,

Question 9

The cell membranes of root epidermal cells contain
_____.

Answer 9

active transport proteins

Question 10

_______________ requires ATP
(energy) to pump mineral ions from the soil into the plant.

Answer 10

Transport protein channels (aquaporins )

Question 11

The high concentration of mineral ions in the plant cells causes water molecules to move into the plant by _____.

Answer 11

osmosis

Question 12

movement of water to the side with the greater concentration of solute (a passive transport of water).

Answer 12

osmosis

Question 13

move water and minerals from the root epidermis into the cortex.

Answer 13

Osmosis and active transport

Question 14

The water and dissolved minerals pass the
inner boundary of the cortex and enter the

Answer 14

endodermis

Question 15

Cells in the endodermis are made waterproof by the

Answer 15

Casparian strip

Question 16

the cytoplasmic continuum

Answer 16

symplast

Question 17

the continuum of cell walls plus extracellular spaces

Answer 17

apoplast

Question 18

As minerals are pumped into the vascular cylinder, more and more water follows by ___

Answer 18

osmosis

Question 19

pushes water through the vascular system of the entire plant.

Answer 19

Root pressure

Question 20

Water in a plant moves along a ____ between the relatively ____ water potential in the soil to successively ____ water potentials in
the roots, stems, leaves, and atmosphere.

Answer 20

gradient; high; lower

Question 21

Water is pulled up
through the xylem:

Answer 21

-Transpiration, Adhesion,
Cohesion, and Tension

Question 22

Water and minerals ascend
from roots to shoots through the ___

Answer 22

xylem

Question 23

Water is pulled upward by
______ in the
xylem (due to water loss called ___)

Answer 23

negative pressure; transpiration

Question 24

water molecules stick to themselves
with hydrogen bonds (____) and to the walls of the
tracheids or xylem vessels (_____).

Answer 24

cohesion; adhesion

Question 25

A tension (pulling force) is generated at the top called _______

Answer 25

transpiration

Question 26

(Proposed by DIXON and
JOLLY in 1894)

Answer 26

Transpiration pull
theory

Question 27

Sunlight powers
photosynthesis and
these sugars are
transported via the
phloem (______)

Answer 27

translocation

Question 28

Materials are
translocated in the
phloem from
_______ to
________

Answer 28

sources (usually
mature leaves); sinks (roots,
immature leaves)

Question 29

(also called mass-flow or bulk flow)

Answer 29

The Pressure-Flow
Model

Question 30

leads to a buildup of sugars (the phloem cells become
hypertonic)

Answer 30

Phloem loading

Question 31

water enters
the phloem (sieve tube)
from xylem (vessel
elements) via

Answer 31

osmosis

Question 32

uses a proton/sucrose co-
transport protein.

Answer 32

Phloem loading

Question 33

leads to lower sugar
concentration (the
phloem cells become
hypotonic)

Answer 33

Phloem unloading

Question 34

phloem turgor pressure ____ in phloem unloading while ____ in phloem loading

Answer 34

decreases; increases

Question 35

Materials translocated in phloem:

Answer 35

mainly carbohydrates; Amino acids, proteins, inorganic ions, and plant hormones

Question 36

– Movement in the phloem is rapid, well in excess of rates of
diffusion
* Average velocity is 1 meter per hour

Answer 36

rate of translocation

Question 37

Sugars and other organic materials are conducted throughout
the plant in the phloem by means of sieve tube elements

Answer 37

Pathway of translocation:

Question 38

The exudation of water droplets (xylem sap) on tips of grass blades or the leaf margins of some small, herbaceous eudicots.

Answer 38

Guttation

Question 39

which often occurs at night, is caused by the continued, active accumulation of
ions in the roots at times when transpiration
from the leaves is very low or absent.

Answer 39

Root pressure

Question 40

Guttation does not take place through the stomata, but instead occurs through
special groups of cells located near the ends of small veins called

Answer 40

hydathodes

Question 41

The evaporation of water vapor from plant surfaces;
especially in leaves (through the stomata), also in stems, flowers, and roots.

Answer 41

transpiration

Question 42

regulate water loss in plants and the rate of CO2 uptake

Answer 42

stomata

Question 43

Stoma is wide open

Answer 43

water is abundant or in day time

Question 44

stoma is closed

Answer 44

water is limited or at night time

Question 45

Guard cells gain and loss water by

Answer 45

osmosis

Question 46

is defined as an increase in the number,
size, and volume of cells; definite (measurable)

Answer 46

growth

Question 47

is the emergence of specialized,
morphologically different body parts; indefinite

Answer 47

development

Question 48

_____ indicates a quantifiable change in size, whereas ______ indicates a transformation of structure

Answer 48

growth; development

Question 49

Internal factors affecting growth and development of plants are the

Answer 49

Plant Growth Regulators (PGRs).

Question 50

External factors that regulate the growth of plants are

Answer 50

light intensity, day length, gravity, touch,
temperature, and water

Question 51

Plant growth is influenced by

Answer 51

phytohormones (plant growth regulators/PGRs)

Question 52

is a chemical produced in one part
of an organism, transported to other tissues
where it has its effect.

Answer 52

hormone

Question 53

are organic compounds produced in
the meristems and transported through the vascular system of the plant.

Answer 53

PGRs

Question 54

PGRs five main groups:

Answer 54

1. Auxin
2. Gibberellin or Gibberellic acid
3. Cytokinin
4. Ethylene
5. Abscisic Acid (ABA)

Question 55

regulators that promotes growth

Answer 55

auxins, gibberellins,
cytokinins.

Question 56

regulators that inhibit growth

Answer 56

abscisic acid and ethylene

Question 57

help regulate gravitropism (change in direction of growth due to
gravity)

Answer 57

auxin

Question 58

It breaks seed and bud dormancy

Answer 58

gibberellin

Question 59

Plant growth is a balance between the actions of ____ and _____

Answer 59

auxins; cytokinins

Question 60

releases apical
dominance of the auxin

Answer 60

cytokinins

Question 61

Called the plant stress hormone because it causes
changes to the plant to protect itself from environmental stress

Answer 61

ethylene

Question 62

Stimulates fruit ripening, leaf and fruit drop, flower and leaf
senescence

Answer 62

ethylene

Question 63

inhibits growth in response to changes in temperature and light
(e.g. seasons); causes bud and seed dormancy

Answer 63

Abscisin/Abscisic Acid (ABA)

Question 64

are steroids chemically similar to
cholesterol and the sex hormones of animals.

Answer 64

Brassinosteroid

Question 65

First isolated from Brassica pollen in 1979,

Answer 65

Brassinosteroid

Question 66

external factors affecting plant growth are

Answer 66

• Light – Energy Source
• Food
• Water
• Temperature
• Soil pH

Question 67

is the irreversible change in size of cells and
plant organs due to both cell division and cell
enlargement.

Answer 67

growth

Question 68

Accounts for the actual increase in plant size

Answer 68

cell expansion

Question 69

Growth can be:

Answer 69

– determinate—when an organ or part or whole
organism reaches a certain size and then stops
growing; or
– indeterminate—when cells continue to divide
indefinitely

Question 70

Plants in general have _____ growth

Answer 70

indeterminate

Question 71

is the progression from earlier to
later stages in maturation.

Answer 71

development

Question 72

The process by which cells with the same genes become
different from each other; cell undergoes change in shape in
order to perform specialized functions.

Answer 72

cell differentiation

Question 73

development involves:

Answer 73

– growth,
– morphogenesis (the acquisition of form and
structure), and
– cell differentiation

Question 74

Plants pass through developmental phases, called

Answer 74

phase changes