L1 Plants

Introduction to Plants : 

Introduction to Plants Plant structures, Signaling defences, Responses to the Environment

Why are plants important? : 

Why are plants important? Food Photosynthesis produces oxygen Roots prevent soil erosion Leaves absorb pollutants Take in Carbon Dioxide

Types of Plants : 

Types of Plants Bryophytes – lack a true vascular system (xylem and phloem) Mosses Remain small Need water to reproduce – sperm swims to female plant to fertilize egg – grows into stalk with spore case on end

Seedless Vascular Plants : 

Seedless Vascular Plants Ferns Have xylem and phloem Reproduce by spores instead of seeds

Seed Plants - Gymnosperms : 

Seed Plants - Gymnosperms Nonflowering seed plants Many produce seeds in cones - conifers “naked seeds” – have no flesh around it.

Seed Plants - Angiosperms : 

Seed Plants - Angiosperms Flowering seed plants Produce flowers containing male and/or female reproductive structures

Seed : 

Seed Produced from union of egg and sperm Egg is in flower – usually deep inside Sperm is in pollen – carried to egg during pollination Fertilization produces embryonic plant within stored food and a protective coating

Pollination : 

Pollination Wind Water Animals – bats, insects, birds, mammals, snails, etc.

Fruits : 

Fruits Attracts animals so seeds get dispersed Seeds usually can pass through animal’s digestive system to be dropped a distance away from parent plant

Structures of Angiosperms : 

Structures of Angiosperms Roots Grow toward water Absorb water and minerals Transport them to stem Store food Anchor plant

Types of Roots : 

Types of Roots Taproot system Fibrous root system

Root Tip : 

Root Tip Remember the root tip we squashed to see the cells undergoing Mitosis? Root cap Zone of cell division Zone of elongation Zone of differentiation

Leaves : 

Leaves You already know the structure of the leaf:

Flower Structure : 

Flower Structure Carpel

Fertilization : 

Fertilization

Vegetative Reproduction : 

Vegetative Reproduction Cuttings - houseplants Runners - strawberries Mutations – naval oranges Grafts Suckers – aspen roots

Plant Hormones : 

Plant Hormones Chemical messengers – made in one part of plant and work on another (just like human hormones). Auxins – responsible for growth at the end of stems – cut them off, and plant will send out shoots from the sides of stems. Pruning uses this info to make bushier plants. Others include cytokinins for root growth, Giberellins for seed growth, ethylene for fruit ripening, and abscisic acid for fruit and leaf growth.

Plant Responses : 

Plant Responses Phototropism gravitropism Thigmotropism hydrotropism

Dormancy in Winter : 

Dormancy in Winter Deciduous Trees Lose leaves in autumn – Why? Low level of metabolism in winte Growth is suspended until leaves grow in spring

Evergreen trees : 

Evergreen trees Metabolism slows in cold weather, but they can start up any time the temperature rises. Lose leaves all year long, a little at a time.

Photoperiodism : 

Photoperiodism Plant responds to intervals of day and night Long night plants – flower in late summer or early fall Short night plants – flower in early to midsummer

How long do plants live? : 

How long do plants live?

Monocots vs Dicots : 

Monocots vs Dicots

How a Plant Grows: : 

How a Plant Grows:

Secondary Growth: : 

Secondary Growth:

Tree trunks: : 

Tree trunks:

Water Transport : 

Water Transport

Fruits: : 

Fruits: Mature ovary

Growth of Seed: : 

Growth of Seed: