BFG Ch 2

Question 1

Purpose of roots (3)

Answer 1

Anchor plant in soil

Absorb water and minerals

Store excess foods

Question 2

Two ways that roots anchor plants in soil

Answer 2

diffuse root system (occupy large shallow area; decreases soil erosion)

tap root system: sends one/two rapidly growing sparsely branched roots straight down to get deep water

Question 3

Storage capacity of roots

Answer 3

tap roots have better storage than diffuse roots.

tap roots can enlarge in diameter as well as length (ex. carrot)

enables plants to regenerate quickly in the spring (new foliage)

Question 4

Tree roots

Answer 4

sometimes can be diffuse systems (unexpectedly)

Advantage for trees to have shallow diffuse roots:

collect nutrients released from rotting vegetation before they’re washed away by heavy rains.

Question 5

drip zone

Answer 5

distribution of tree roots to catch the dripping rainwater from their branches

Question 6

horticultural and agronomic root systems

Answer 6

usually shallow; wild counter parts can have much deeper tap roots.

Question 7

Describe root growth (components, branching)

Answer 7

Apical meristems (1/4” at tip of roots)

covered by root cap: cells that are readily rubbed off if need be to protect the meristems

root hairs occupy a set region after the meristems to increase by several 100x the absorptive surface of the organ.

Branching begins in slightly older root sections deep within the parent root and tend to grow at right angles.

Question 8

What is a shoot

Answer 8

the principle aerial stems, branches, and attached leaves of a plant

Question 9

Apical bud

Answer 9

stem’s growing tip; much more complex than a root’s

Question 10

Apical bud of a stem

Answer 10

involved in cell devision and elongation

initiates the arrangement of leaves on the stem

makes provisions for the eventually development of branches

occupies about 1/10” of stem.

Question 11

Components of the apical bud

Answer 11

apical meristem: dome of actively dividing cells

leaf primordia (on either side of meristem): fold over and protect meristem

axillary bud primordium at base of leaf primordia
-site of future branching

Question 12

Nodes and internodes

Answer 12

Nodes: point where leaf and axillary bud primordia develop

internode: section of stem between nodes; spread the leaves apart to ensure maximum exposure to sunlight

Question 13

Basic leaf arrangements by the apical meristem placement of leaf primordia

Answer 13

alternate

opposite

whorled

Question 14

Why do plants bother making axillary buds?

Answer 14

to act as points of reserve branch growth in the case apical buds are destroyed by disease, frost, wind, or animals

usually developed low on the stem to maintain a low center of gravity (until wood)

Question 15

What evolved to increase the capacity of support in upright growing plants?

Answer 15

wood

Question 16

trees

Answer 16

one or a small number of main trunks to support their leaf crowns

Question 17

shrubs

Answer 17

smaller plants with many woody stems branching closer to the ground

Question 18

Roots of woody plants

Answer 18

develop a wood core as a consequence of their age and in conjunction with the thickening of trunks and branches.

roots maintain their important role as anchors and transport ever-increasing amounts of water to supply the needs of aboveground parts.

Question 19

Ground covers

Answer 19

plants that grow along the ground instead of upward to avoid the expensve of supporting a trunk

-ivy, some grasses

Question 20

advantage to elevating leaves upright

Answer 20

woody plants:

get more sunlight

Question 21

secondary growth

Answer 21

when plants increase their supportive role- usually making wood

pretty costly

Question 22

Features of a woody twig

Answer 22

Transition: green to brown, hardens.

Outer bark = cork

Lenticils: breathing pores that appear as bumps on bark

leaf scars: reminders of foliage that fell; dots represent where food/water conducting cells were sealed off.

bud scales: form a tight apical/terminal bulb in the winter to protect the dormant bud

concentric rings of scars left after the bud scales fall off (count the rings to find out twig’s age) = called Terminal bud scars

Question 23

Leaf blades

Answer 23

must be thin and translucent to allow light to penetrate

held in outstretched positions

often attached to a petiole (leaf stalk) to allow rotation of leaf blade to track sun and greater flexibility

Question 24

petiolate leaf

Answer 24

a leaf with a petiole

Question 25

sessile leaf

Answer 25

one in which the blade is directly attached to the stem

Question 26

simple leaves are divided into..

Answer 26

leaflets or compound leaves.

Question 27

Greater the number of leaf divisions..

Answer 27

the more feathery the appearance of the leaf

Question 28

Advantage of compound leaves

Answer 28

permit light to pass between leaflets to lower ranks of leaves.

lighter weight.

Question 29

pinnately compound leaves

Answer 29

leaflets are arranged around a central axis

Question 30

palmately compound leaves

Answer 30

one point at the tip of the petiole where leaflets arise.

Question 31

Pinnate venation, palamte venation, parallel

Answer 31

arangements of vein patterns within leaf blades

Question 32

leaf features

Answer 32

shape of blade, shape of leaf apex and base, type of leaf margin

Question 33

Damage a leaf, what happens?

Answer 33

nothing. no repair mostly.

grass blades are an exception because they grow from the base.