Lecture 2-Plant physiology

Question 1

vascular bundle in leaves

Answer 1

between sclerenchyma bundles, enclosed by living cylinder of cells

Question 2

Growing upwards, what came first?

Answer 2

lignified tissue xylem

Question 3

Plants that undergo secondary growth

Answer 3

some annuals like sunflowers, all trees and vines

Question 4

Primary to secondary growth

Answer 4

zone of division in region between vascular bundles called VASCULAR CAMBIUM. inside forms secondary xylem, outside forms secondary phloem. epidermis ruptured and replaced by cork and periderm formed by cork cambium

Question 5

Annual plant prim. or sec.?

Answer 5

Usually just primary body (derived from embryo)

Question 6

Perennial plants prim. or sec.?

Answer 6

P and S body.
phloem replaced every year (prev. is crushed) S
Xylem replaced every year (prev. stays in place)S
Leaves replaced every year P

Question 7

Three ways of water movements

Answer 7

inside living cells-symplastically
between cells-apoplastically
into cells (sym) then out into apo. only to re-enter cell-transmembrane pathway

Question 8

How does water enter root?

Answer 8

root hairs and root tips

Question 9

Minerals that are accepted? rejected?

Answer 9

Ca accepted. Na Ni rejected

Question 10

Can water move apoplastically past endodermis?

Answer 10

No, waxy water-repellant layer (Casparian Strip)

Question 11

Bulk flow

Answer 11

water movement, driven by evaporation

Question 12

Cohesion-adhesion theory

Answer 12

water molecules pull each other along using co and adhesion

Question 13

Transpiration

Answer 13

water loss by aerial organs

Question 14

Stomates

Answer 14

opening and closing can regulate effect of evaporation, causes 95% of water loss

Question 15

Stomate opens because

Answer 15

K+ pumped in, water follows, guard cells balloon

Question 16

Stomate closes because

Answer 16

k+ pumped out, water follows, guard cells lose h2o and shrink

Question 17

Abscisic acid

Answer 17

hormone produced in roots b/c of water deficiency, causes closing of stomata

Question 18

Easy water movement through plant?

Answer 18

apo is easiest, symplast is easy too

Question 19

How does water get past lipid bilayer surrounding living cells?

Answer 19

protons establish membrane potential
co-transport of neutral solutes w/ protons.
co-transport of ions (nitrates) with protons

Question 20

Aquaporins

Answer 20

bidirectional channel proteins.
single file transport of water (10 at a time)
3 billion/s
decrease rate if cell more acidic and increase in cellular Ca ion concentrations

Question 21

solute potential

Answer 21

directly proportional to molarity of solution. aka osmotic potential

Question 22

pressure potential

Answer 22

physical pressure on soultion

Question 23

Turgor pressure

Answer 23

pressure exerted by plasma membrane against cell wall and cell wall against protoplast

Question 24

protoplast

Answer 24

living part of cell including plasma membrane