Flowers, Fruits, and Seeds COPY

Question 1

what are the epigenetic changes of gene expression in vernalization?

Answer 1

changes in the gene expression that can be passed on to the descendent cells through mitosis, without changes in the DNA
sequence

Question 2

self-propagating

Answer 2

• florigen
• a given induced shoot can stimulate flowering in repeated
  grafts
• and a given shoot can stimulate flowering in a graft and a shoot from that graft can stimulate flowering in another graft etc.

Question 3

mature stamens and carpels

Answer 3

• develop anthers that generate microspores that mature into pollen, and the carpel tissue develops an ovule inside an ovary

Question 4

what is the process of the ovule and its 4 megaspores?

Answer 4

The ovule generates four megaspores, with only one surviving (the other four are
apoptotic megaspores), this one cell undergoes three mitosis events, ultimately
resulting in a seven cell megagametophyte (three antipodal cells, an egg cell, two
synergids, and a large, double nucleated central cell (which ultimately will become the
endosperm

Question 5

microscopes in mature anthers

Answer 5

When the microspores are mature the anthers burst releasing the tricellular pollen into the air
or it is picked up by a pollinator

Question 6

what must happen for pollination to occur?

Answer 6

pollen must land on the stigma where one of the cells (the tube nucleus cell) forms a pollen tube leading to the ovule

Question 7

pollination

Answer 7

• pollen must land on the stigma where one of the cells (the tube nucleus cell) forms a pollen tube leading to the ovule
• When the pollen tube reaches the ovule the remaining two sperm cells enter the micropyle and
  one cell binds with the egg cell to form a zygote that develops into the embryo, while the other
  cell binds with the double nucleated central cell that forms the endosperm that feeds the developing embryo
• As the embryo develops, it absorbs the endosperm transitioning torpedo stage, and ultimately
  the entire ovule matures into a seed
• if all of this occurs in one flower it is called selfing
• other are self incompatible and require outcrossing

Question 8

what is the final stage of seed development?

Answer 8

maturation

Question 9

maturation

Answer 9

• in most species, very little embryo remains

- the seeds gain desiccation tolerance and dry out, which promotes seed longevity

Question 10

in most species when seeds mature, very little of the embryo remains. However, what happens to the embryo in cereal grains and other monocots?

Answer 10

• retain their endosperm

- endosperm separates into 2 distinct tissues - aleurone and starch endosperms

Question 11

albuminous

Answer 11

seeds that retain their endosperm at maturity

Question 12

exalbuminous

Answer 12

those that do not retain their endosperm at maturity

Question 13

pericarp

Answer 13

• albuminous seeds develop a pericarp or hard outer coating
• some species the develop a pericarp need to be scarified (scratched), pass
  through the digestive tract of an animal, or even burned to promote germination

Question 14

seed longevity

Answer 14

= the ability of the seed to remain viable in the dry state over long periods of time

Question 15

orthodox seeds

Answer 15

• can tolerate tolerate desiccation and storage in a dry state
• only some species have seeds that dry out completely

Question 16

recalcitrant seeds

Answer 16

• species that cannot be stored for long periods, remain relatively active
  metabolically and retain relatively a highwater content
• avocados, mangos

Question 17

what are fruits?

Answer 17

seed-dispersal units and they can be grouped according to several features, e.g.,
moisture content or composition

Question 18

angiosperm seeds

Answer 18

• are encased fruit

- not all are fleshy

Question 19

dehiscent

Answer 19

the fruit splits to release the seed

Question 20

indehiscent

Answer 20

fleshy fruit

Question 21

berries

Answer 21

• seeds enclosed in a fleshy mass

- tomatoes, bananas and grapes

Question 22

drupes

Answer 22

• seeds enclosed in a stony endocarp

- peaches, plums apricots, almonds

Question 23

pome fruits

Answer 23

the fleshy part is derived from accessory structures

- apples and pears

Question 24

simple fruits

Answer 24

• mature single or compound ovary
• hazelnut, Arabidopsis,
  tomato

Question 25

aggregate fruits

Answer 25

• flowers that have multiple carpels that are not joined together
• raspberry

Question 26

multiple fruits

Answer 26

• fruit is formed from a cluster of flowers and each flower produces a
  fruit
• pineapple