Lecture 20: Seed and Root Development

Question 1

what are the components of an angiosperm seed?

Answer 1

embryo, endosperm, seed coat

Question 2

what does the endosperm store?

Answer 2

starch, protein, lipids

Question 3

what kind of tissue cells is the seed coat of an angiosperm made of?

Answer 3

sclerenchyma

Question 4

_____ increases the chances that germination will occur

Answer 4

seed dormancy

Question 5

breaking seed dormancy requires _____

Answer 5

environmental cues

Question 6

how long are dormant seeds viable? on average

Answer 6

1-2 years, some for days, some for centuries, the oldest seed is 2000 years old!

Question 7

to enter dormancy, a seed has to lose lots of ____ and obtain lots of _____

Answer 7

1. water
2. macromolecules

Question 8

what does germination depend on?

Answer 8

imbibition (uptake of water due to dry seed)

Question 9

the _____ of a seed emerges first after germination to anchor plant, then the ___ breaks through the soil

Answer 9

1. radicle
2. shoot tip

Question 10

what are the main functions of a root?

Answer 10

anchoring plant, absorbing minerals/water, storing carbohydrates

Question 11

what is the function of root hairs?

Answer 11

higher surface area = higher uptake of water

Question 12

where does primary root growth occur?

Answer 12

the RAM

Question 13

what two things does the RAM produce?

Answer 13

the root cap to protect root tip, and proximal cells to maintain root shape and size

Question 14

where does growth occur in the root? (three zones)

Answer 14

zone of cell division
zone of elongation
zoe of differentiation/maturation

Question 15

protecting RAM as it pushes through soil, secreting polysaccharide slime, sensing gravity to grow downwards, and sloughing off old cells are all characteristics of the ______

Answer 15

root cap

Question 16

what is the innermost layer of the cortex?

Answer 16

endodermis

Question 17

the ____ regulates the passage of substances into the plant

Answer 17

endodermis

Question 18

how can you visually tell the difference between a monocot and dicot root?

Answer 18

monocot: ring pattern
dicot: random pattern

Question 19

lateral roots arise from the ____ and are in line with the ____ for transport

Answer 19

1. pericycle
2. xylem

Question 20

what kind of plants have a tap root system?

Answer 20

tall plants and large shoots

Question 21

adventitious roots that come from stem, lateral roots, and shallow depth are all traits of the _____ system

Answer 21

fibrous root system