CONTENTS:
1.
Characteristics of plants.
2.– Classification of plants: . – Without flowers . – With flowers.
3.– Parts of a plant: roots / stem / leaves / flowers.
4.– Vital functions of a plant:
a . – Nutrition: .- Photosynthesis . – Respiration . – Transpiration.
b.– Interaction.
c.– Reproduction:
c.1.– Sexual reproduction in plants with flowers: Pollination / fertilization / fruit, germination...
c.2.– Asexual reproduction in plants: Spores, bulbs, tubers, stolons, vegetative reprod…
1.- CHARACTERISTICS OF PLANTS.
PLANTS are multicellular living beings with chlorophyll that can produce their own food and they can’t move from the soil.
1.
Plants contain chlorophyll (gives green colour) to produce their own food (photosynthesis). So they have autotrophic nutrition.
2.- They can’t move from the soil.
3.- They are multicellularorganisms with nucleus.
2.– CLASSIFICATION OF PLANTS:
There are two groups:
1.– Plants without seeds: moss and fern.
2.– Plants with seeds:
a.– Angiosperms: with flowers, seeds and fruit (apple)
b.– Gymnosperms: without flowers. naked seeds. (pine)
2.1.– Plants without seeds: like moss and fern
They reproduce by spores.
Moss: are small plants without real roots, stem or leaves. They are fixed on rocks, soil and trees. They usually live in dark, cold and wet places…
Fern: are bigger plants. They have a stem what grows horizontally. They have roots and tall leaves. They like to live in the shade and wet places. Under their leaves, they have sori to produce spores.
2.2.– Plants with seeds: (grass, bushes, trees
There are many plants in this group, but we can divide them in:
a.- Angiosperms: (flowering plants), they produce beautiful flowers that later will transform into seeds.
b.- Gymnosperms: (with naked seeds), and they are plants like conifers (pines, cypresses…)
USEFUL WORDS:
. – chlorophyll . – autotrophic nutrition
. – moss . – fern . – sori (sorus)
. – spores . – seed plants
. – gymnosperm . – angiosperm
3.- PARTS OF A PLANT:
All plants with flowers have the same structure.
THE PARTS OF A PLANT are:
. – Roots: absorb water and nutrients.
.
– Stem: gives support and transports nutrients.
. – Leaves: make food (photosynthesis)
. – Flower: reproductive system of the plant.
3.1.– ROOTS:
They are under the soil. They fix the plant, and absorb water and nutrients.
There are different kinds of roots:
.
.
Primary root with a taproot.
– Secondary roots with lots of root hairs absorb water and minerals.
3.2.- STEM: supports the rest of the plant. It also transports nutrients from roots to leaves.
There are two kinds of plants depending on their stems:
a.-Woody plants: They have a trunk, and produce wood.
b.-Herbaceous plants: they don’t produce wood, and they die at the end of season.
3.3.- LEAVES:
They are green because of the chlorophyll. They make food for the plant (photosynthesis).
It has two parts: - The petiole: links the leaf to the stem.
- The blade: the main part of the leaf. They have two sides:
.
.
The upper side is very bright.
The lower side with many small openings called stomata to regulate the exchange of oxygen and water to the atmosphere.
There are evergreen plants have leaves in all seasons, and deciduous plants that lose their leaves in autumn.
FLOWER Helps in reproduction
LEAF Performs photosynthesis
FRUIT Protects the seeds STEM Supports the plant
ROOT Absorbs water and minerals
ROOT Absorbs water minerals
3.4.
– FLOWERS:
are the reproductive organs of plants.
Parts of the flower:
.
- All petals form the corolla to attract insects.
- All sepals form the calyx to protect the inner organs.
- The stamenis the male part of the flower and it is formed by the anther (with pollen) and the filament
- The pistil is the female part of the flower and it is formed by stigma, style and ovary with ovules.
. – roots . – root hairs .- stem . – trunk
. – leaves . – petiole . – blade . – stomata
. – flowers . – stamen . – filament . – anther .
.
sepals/calyx . – pistil . – stigma . – style
ovary . – ovules . – sedes
. – petals /corolla
1.- NUTRITION:
.
– Photosynthesis: plants use water, CO2 and light, to obtain sugars and oxygen.
.
– Respiration: plants use oxygen and sugars to obtain energy, and expel CO2.
. – Transpiration: plants expel excess water through stomatas on leaves.
A.1.–PHOTOSYNTHESIS:
It is the process used by plants to make their own food.
They need water, minerals, carbon dioxide and sunlight
Roots absorb minerals and water from the soil. They form the raw sap.
Leaves have chlorophyll in the chloroplasts, that gives them their green colour.
Leaves get carbon dioxide and sunlight from the air.
Leaves transform these components into sugars and oxygen.
Elaborated sap are sugars that give energy to the plant to grow and live.
The plant expels oxygen to the air.
A.2.– RESPIRATION:
All living beings breath, so plants breath too.
Plants get oxygen and expel carbon dioxide and water, to transform sugars into energy to grow.
Plants breath mainly during the night, when there isn’t any light. For this reason it is dangerous to have plants in the bedroom at night.
A.3.– TRANSPIRATION:
Roots absorb a lot of water from the soil, but only a small amount of this water is used in photosynthesis.
Plants will expel the extra water through stomatas on leaves.
USEFUL WORDS:
. – autotrophic nutrition . – xylem sap . – pholem sap
. – photosynthesis . – chlorophyll . – respiration
. – carbon dioxide . – glucose /sugars .- transpiration
Plants don not have sense organs or nervous system, but they can react to some stimuli: light, humidity, gravity, temperature, …
They cannot move from the soil, but they can move only a bit. They can move their stems and leaves to the light. Their roots into the soil looking for water and nutrients…
There are two kinds of reactions:
A.- Tropism: depending on the direction of the stimulus:
Phototropism: in response to light.
Hydrotropism: in response to water.
.
Geotropism, in response to gravity.
.
B.– Nastic movements: when they react to touch
C.– REPRODUCTION IN PLANTS.
Plants can reproduce in two ways:
.
Sexual reproduction: in flowering plants.
. – Asexual reproduction.
C.1.– SEXUAL REPRODUCTION IN PLANTS WITH FLOWERS:
Flowers are the reproductive organs in plants. They have:
. - Stamen (male part) produce pollen.
. – Pistil (female part) produce ovules. In the reproductive process there are some stages:
1.- POLLINATION.
Pollination is the process in which pollen from the anthers of a flower is transported to the stigma of the flower.
There are different ways of pollination: through animals like birds or insects, through the air or water...
2.- FERTILIZATION.
When a grain of pollen reaches an ovule and both form a new seed.
1.- Pollen falls down on the stigma, and forms a tube (pollen tube).
2.– The grain of pollen gets the ovary and joins to an egg cell to form a seed.
3.- FRUIT FORMATION.
After fertilization, petals from the corolla fall down, the ovule will transform into a seed, and the ovary will transform into the fruit.
4.- GERMINATION.
If a seed falls down on the soil, and there is enough waterand heat, it will germinate and it will form a new plant.
Germination is the process in which plants emerge from seeds and begin to grow.
First the seed breaks, the radicle and starts to grow into the soil, later first leaves emerge, producing a new plant.
SEXUAL REPRODUCTION in plants with flowers:
1.– Pollination: pollen from the anthers is transported to the stigma of the flower.
2.– Fertilization: Pollen forms a pollen tube, and get the ovary to join an egg and form a seed.
3.– Seed and fruit formation: the ovule will transform into a seed, and the ovary into a fruit.
4.– Germination: seed falls down on a soil, with enough water and heat, it will form a plant.
C.2.– ASEXUAL REPRODUCTION IN PLANTS:
Asexual reproduction is the process when a part of only one plant develops into a new young plant.
Types: spores, bulbs, tubers, stolons, vegetative reproduction
1.– Spores: plants without flowers like moss produce spores that germinate and produce new plants. Fern have sori under their leaves, that produce spores.
USEFUL WORDS:
.
fertilization .
pollen tube
. – seed formation . – germination
. – radicle
2.– Bulbs: are short stems with leaves that contain food reserves, and can produce more plants in the following growing season.
Examples: onions, garlic, tulips…
3.– Tubers: are plant structures that store nutrients, used by plants to survive the winter or dry months. They will produce new plants.
Examples: potatoes, carrots...
4.– Stolons (or runners): are stems that grow at the soil surface and produce new roots and new plants from the buds.
Examples: strawberries...
5.– Vegetative reproduction: is the process of formation of new plants from a portion of a vegetative part of the plant: root, stem,.. These parts are capable of producing a new entire plant.
Examples: most of plants and trees.
USEFUL WORDS:
. – spores . – bulbs . – tubers
. – stolons / runners . – buds
. – vegetative reproduction / propagation