Biology Ch. 36: Seeds and Seedlings

Question 1

cotyledon

Answer 1

seed leaf

will provide nutrients for growing tissues in the germinating seedling

Question 2

foliage leaf

Answer 2

cluster of leaves at the tip of the shoot apical meristem

called the plumule

Question 3

primary root

Answer 3

from the radicle
becomes the primary root when it breaks through the seed coat into the soil
marks the completion of germination

Question 4

monocotyledon

Answer 4

also knows as the monocots

embryo only has one cotyledon

Question 5

radicle

Answer 5

embryonic root
located near the micropyle
attaches to the cotyledon at a region of cells called the hypocotyl

Question 6

aleurone layer

Answer 6

separates endosperm from the pericarp
manufactures enzymes that digest components of endosperm cell walls and others that digest macronutrients for use by cells of the young root and shoot

Question 7

dicotyledon

Answer 7

dicot

embryo has two cotyledons

Question 8

coleoptile

Answer 8

sheath of cells that protects the shoot apical meristem during upward growth through the soil
in the grasses

Question 9

coleorhiza

Answer 9

sheathes the radicle until it breaks out of the seed coat and enters the soil as the young plant’s primary root

Question 10

endosperm

Answer 10

triploid tissue in the embryo

provides nourishment for the embryo and, in monocots, the seedling, until its leaves form and photosynthesis begins

Question 11

epicotyl

Answer 11

part of the embryo
has the shoot apical meristem at its tip
often bears the plumule (tiny foliage leaves)

Question 12

imbibition

Answer 12

process in which water molecules move into the seed, attracted to hydrophilic groups of stored proteins
as water enters, the seed swells, the coat ruptures, and the radicle begins its downward growth into the soil

Question 13

dormant

Answer 13

BOOK

Question 14

lateral root

Answer 14

from the pericycle

growth through the cortex and epidermis of the roots

Question 15

germination

Answer 15

seed germination begins when the seed begins to soak up water (imbibiton)
-hydrated embryo begins growth
once germination is underway, the embryo loses the protection of the seed coat and other structures that surround it

Question 16

hypogeous

Answer 16

cotyledon remains below the ground during germination

Question 17

epicotyl

Answer 17

cotyledon pulled above ground during germination

Question 18

how is the shoot apex protected in a

• monocot seedling?
• hypogeous dicot
• epigeous dicot

Answer 18

monocot
-coleoptile
epigeous
-cotyledon
hypogeous
-coleoptile

Question 19

in seeds lacking endosperm, what serves the same function

Answer 19

cotyledons

Question 20

what is the advantage to having the primary root emerge before the shoot

Answer 20

growing shoot system will have a supply of water and minerals
turgor pressure will help cell elongation

Question 21

how is the root tip protected

Answer 21

cap cells

• lubricate the tip and eases the root’s passage through the soil
• guide the root tip downward

Question 22

in what ways is the seedling the most vulnerable stage of the seed-plant

Answer 22

dries out fast
limited food source
if any part of the root or stem is destroyed it can’t live

Question 23

what conditions are commonly required for seed germination

Answer 23

wet - allows imbibition

temperature

Question 24

how do the plane of division & direction of cell expansion affect the form of the plant

Answer 24

plane
-transverse - adds height
-sagittal - adds girt
direction of cell expansion
-the cell will expand once it has gone through mitosis
-direction of cell expansion depends on the orientation of the newly formed cellulose microfibrils
–if microfibrils are randomly oriented, the cell expands equally in all direction
–if they are oriented at right angles to the cell’s long axis, the cell expands lengthwise
–if they are oriented parallel to the cell’s long axis the cell expands laterally