22.3 Seed Plants

What are seeds?

Every seed contains a living plant ready to sprout as soon as it encounters the proper conditions for growth.

Seed Parts

Seeds allow plants to reproduce without water.

Parts Seed Coat - protects the embryo Cotyledon - inside seed, used to absorb food from

endosperm for the developing plant embryo Monocots (1 cotyledon) vs. Dicots (2 cotyledons)

Embryo- baby plant; has tiny root, stem and cotyledons (develop into leaves)

Endosperm – built in food supply for the seed.

Germination of Seeds

Germination - development of embryo inside seed into a new plant with proper environment.

Seed DispersalMovement of seeds for germination

By wind, water, animals eating fruits and depositing seeds or carrying seeds on fur

Types of Seed Producing Plants

Gymnosperms

Angiosperms

Gymnosperms Plants that produce “Naked” seeds (exposed on the scales

of cones) can reproduce without free-standing water, via

pollination

– ADAPTATIONS– Seeds (embryo & food supply)

– seeds allow plants to disperse to new places

Gymnosperms do have naked seeds (not enclosed by a fruit).

CYCADS

CONIFERS

GINKGOS

Angiosperms (Flowering Plants) – Adaptations:

– Vascular tissue– Flowers (reproductive

structure)– Seeds develop within

ovaries– Fruit - ripened ovary

Vascular Plant Crash Course

Pollen

In seed producing plants: Male gamete is called a pollen grain.

Pollen grains are carried wind or animals to the female reproductive structure = pollination.

Pollination Pollination - is the transfer of pollen from the male

reproductive structure to the female reproductive structure.

Types of Pollination Wind or animals.

Wind is far less efficient – So these plants rely on high a volume of pollen to ensure pollination.

Structure of a Flower

There are both male and female parts in flowers!!

Female Part = Pistil – Includes three parts: stigma, style, and ovary Stigma – sticky surface at the top of the pistil; traps and holds

the pollen Style – tube-like structure that holds up the stigma Ovary – has the seeds inside and turns into the part of fruit

that we eat Ovule – part of the ovary that becomes the seed

.

Structure of a Flower

Structure of a Flower

Male Part = Stamen – Includes two parts: the anther and filament. Anther – part of the stamen that is located at the end of the

filament. produces/contains pollen Filament – Part of the stamen that supports the anther Pollen Grain – Produced in the anther. Is the male gamete in

flowers.

Sepal – Protected the flower when it was in bud

Petal – Attract pollinators

The Structure of Flowers

Flower Structure

Sepals and Petals

Flower Structure

Stamens = filament and anther Anthers – produce pollen grains

Flower Structure

Pistil = Stigma, Style, and Ovary Ovules – located inside the ovary – develop into seeds

after pollination.

Perfect Vs. Imperfect Flowers

Two Classes of Angiosperms Monocot & Dicot

lily

grass

Oak tree

Cherry Tree

Monocots and Dicots