Development of Seeds

(1)

Development of Seeds

• First vascular plants on land had spores

(2)

spores sporangium open sori cover ed sori

(3)

(4)

• Unusual gymnosperms

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

Bittersweet miniature embryo

(14)

(15)

(16)

Orchid seed

Seed coat

(17)

Corn seed Seed coat Endosperm Scutellum Radicle Coleorhiza Coleoptile Plumule

(18)

Pine seed

Embryo (2N)

(19)

Pine seed

Cotyledons Hypocotyl

(20)

(21)

• Storage tissues

– Monocots = starchy endosperm

(22)

– Dicots = cotyledons and little or no endosperm

Starchy cotyledon

em

(23)

– Gymnosperms = haploid (1N) gametophytic tissue

(24)

Pine seed

Gametophytic tissue

(25)

(26)

(27)

Generative nuclei = “sperm”

(28)

(29)

(30)

(31)

(32)

(33)

(34)

(35)

(36)

(37)

(38)

(39)

(40)

(41)

(42)

(43)

(44)

(45)

(46)

(47)

Fruit development in blackberry

Poor pollination/fertilization

(48)

Fruit development in strawberry

(49)

Vegetative parthenocarpy

(50)

(51)

(52)

(53)

(54)

Stimulative parthenocarpy

(55)

(56)

Acer saccharinum

“silver maple”

Quercus macrocarpa

(57)

Unusual types of seed development

• Polyembryony

– The development of multiple embryos within the same seed

(58)

Polyembryony

Sexually produced Clone of

Mother

Both grew from 1 seed!

Bull

(59)