Kingdom Plantae

multicellular, eukaryotic, autotrophs that do photosynthesis by using a variety of pigments: or carbon dioxide + water sugar (glucose) + oxygen plants all have cell walls made of cellulose many plants are green; this is because of the pigment chlorophyll Plant Cell - Parts to Know cell wall (cellulose) nucleus cell membrane chloroplast:

a stack of thylakoids is a granum (plural: grana) generally non-motile all plants have an alternation of generations (generations alternate between N and 2N) egg + sperm

mitosis to make gametes Haploid (N) gametophytes Diploid (2N) sporophytes

meiosis to make spores

gametophyte is the haploid stage of a plant sporophyte is the diploid stage of a plant

Kingdom Plantae is Divided into 5 Main Categories 1. algae 2. mosses 3. ferns 4. gymnosperms 5. angiosperms Algae usually multicellular, always have chlorophyll a are only found in or around water because they do not have adaptations to live on land water gives them food, structure, and allows for reproduction algae are very important: they produce about 70% of the worlds oxygen they are primary producers in aquatic environments algae are used to make agar, toothpaste, ice cream, candy bars, and sushi Life Cycle of Algae: many sporophytes and gametophytes look the same (eg. ulva, below) although it is difficult to tell, since they look the same, the gametophyte is the dominant stage (longer living, more adaptations, independent, photosynthetic, larger) Phylum Chlorophyta: Green Algae all have chlorophyll a and b Why are plants green? Notice, in the graph to the right, that green light is not absorbed by either chlorophyll a or chlorophyll b. store excess energy as starch examples: ulva (sea lettuce) - see life cycle: note diploid and haploid generations

 volvox (colonial)

spirogyra (filament)

Phylum Phaeophyta: Brown Algae pigments: chlorophyll a and c; fucoxanthin store excess food as oil many brown algae have air bladders to help them float examples: bullwhip: blade - does photosynthesis gas bladder - stores air stipe - supports the algae holdfast - for anchorage fucus (rockweed) - living in intertidal zones has its challenges: they have to be able to store water and survive waves (see here for more information) Phylum Rhodophyta: Red Algae have a special pigment called phycoerythrin, which is very good at using blue light (this is Bullwhip important because nutrients are found at the bottom, and only blue light reaches this far; algae need the light for photosynthesis) some red algae can be found at depths of 260 m Mosses and Liverworts

mosses are found in phylum Bryophyta, and they are the first land plants living on land created many challenges for plants: 1. obtaining water for all cells 2. have support structure to expose leaves to sunlight (if the leaves are stacked on top of one another, then the bottom ones will not receive much sunlight) 3. they need to be able to exchange CO2 and O2 without losing water

4. moving nutrients around the plant, from roots to leaves (plant cells need to specialize and work together to survive, while algae cells are basically everyone for themselves) 5. need to be able to reproduce without standing water Bryophyta have adapted well to living in wet habitats but have no adaptations for living in arid (dry) environments Two main adaptations: 1. stem-like structures for support 2. root-like structures, called rhizoids, for anchorage and gathering minerals Do not have: 1. way of retaining water 2. a transport system for water or nutrients 3. way of reproducing without standing water (see p. 454, Figure 21-6 in textbook)

Note: the gametophytes are dominant in moss. Human Uses: mosses can be used for fuel after drying; used in gardening for adding moisture to soil; often found in bogs and allow organic material to be preserved

Ferns phylum Tracheophyta has over 11 000 different species well adapted to living on land - are the first land plants to have vascular tissue and cuticles have underground stems called rhizomes What is vascular tissue? transport tissue within the plant there are two types: xylem and phloem xylem: transports water up from the roots main type of cells are tracheid cells: these are hollow and dead acts like a straw so that water has a tube to go up: water molecules are attracted to each other; as water is used in the leaves, the water molecules follow along tracheid cells have very thick walls, which provide support for the plant phloem: transports sugar - usually sugar moves downwards, as sugar is made in the leaves and stored in the roots in spring, sugars may need to be transferred upwards to create new leaves phloem cells are alive; the main types of cells are called sieve cells How do ferns conserve water? mosses lose significant amounts of water due to evaporation; fern have developed a cuticle, which is a waxy layer on their leaves; this waxy layer has holes in it, called stomata, which allows gas exchange but inhibits water loss Fern Life Cycle: like all plants, ferns have an alternation of generations these are the first plants to have a dominant sporophyte stage

the main reason why ferns are not perfectly adapted to living on land is because they need standing water for fertilization Human Uses: look pretty; fiddleheads are edible; Azolla is used for crop rotation with rice (it adds nitrogen to the soil) As we go through plants, the sporophyte generation becomes more and more dominant.

Seed Plants
There are 2 types of seed plants: Gymnosperms Angiosperms Both of these plants create seeds. Seeds are baby plants in a protective box with food (they can survive harsh conditions, being eaten by animals, etc.) Best at living on land - all 5 adaptations Gymnosperms In gymnosperms (gymno = naked; sperm = seed), the seeds are not enclosed in a fruit (no flowers either); this is why they are called naked seeds. The most important phylum in gymnosperms in Coniferophyta; these are the evergreens. There are over 550 species of conifers which often live in many unfavourable conditions: cold places: lose little heat leaves in the shape of needles or scales (less surface area) dry conditions: have the thickest cuticles, in general places with low nutrients: best at having mycorrhizae examples: spruce, pine, Douglas fir, cedar, hemlock Gymnosperms have vascular tissue. It is similar to fern vascular tissue except stems grow much thicker. Old tracheid cells become crushed by pressure and stop conducting water. This is called heartwood. Scattered throughout the xylem are resin ducts. These have very sticky substances called resin, which inhibits invasions by fungi, insects, bacteria, and viruses. Why are conifers useful? Mycorrhizae see fungi White spruce tree is the main source of paper Fuel burn wood for heat and energy Lumber build cool things: houses, schools, boats, hockey sticks Life Cycle: alternations of generations, the dominant stage is the sporophyte the sporophyte has male and female cones the male cones have structures called microsporangia; these produce pollen grains by meiosis (pollen grains are the male gametophytes) female cones contain the ovule, which produces the egg; eggs are produced by meiosis female gametophytes make eggs - the structure that makes eggs, according to the textbook, isthe OVULE female cones also produce a sticky substance to catch pollen

pollen is transported by wind, insects, or birds when pollen lands, it breaks open and releases sperm and enzymes the enzymes released create a pollen tube which allows sperm to reach the eggs fertilization occurs and a zygote is formed the zygote grows by mitosis to form an embryo the embryo is protected by a seed; the seed will grow into a new sporophyte Layers of Wood

There are 5 layers to wood. These layers help with transport, support, and protection. Unlike smaller plants, conifers have a large amount of woody tissue. Layers starting from outside:

Functions 1. Cork - protection of the tree this layer includes bark 2. Phloem - transports sugar, generally downwards 3. Vascular Cambium Layer produces new xylem and phloem cells only place where vascular tissue is made 4. Xylem - transports water very important for support most resin ducts are found here 5. Heartwood - compressed xylem cells that no longer transport water heartwood is very important for support in larger trees Angiosperms most widespread plants on land same general features as gymnosperms (eg. cuticles, seeds, vascular tissue, pollen) have improved tracheid cells called vessel cells: these are much larger and better at transporting water reproduce sexually by producing flowers which will, when fertilized, enclose seeds in fruit includes 2 main types:

Monocots parallel veins branched veins

Dicots

flower parts in multiples of 3 vascular tissue bundles are scattered

flower parts in multiples of 4 or 5 vascular tissue bundles are found in rings

monocot means one cotyledon*

dicot means two cotyledon*

*Cotyledon means seed leaf.

Structure of a Flower

sepals - are for protection of the growing flower petals - attract animals to transport pollen (nectar) stamen (male) - contains the filament and anther anthers produce pollen filaments give height so that animals will brush against the anthers and pick up pollen pistil/carpel (female) - contains the stigma, style, and ovary the stigma secretes a sticky substance to catch pollen the style is just to raise the stigma up the ovary contains the ovule; the ovule makes the eggs Why have flowers? - pollination is essential for reproduction flowers attract insects, birds, and mammals using their scents, colours and nutritional value (nectar); these animals transport pollen from plant to plant flowers that use wind for pollination have flowers with little fragrance or colour Life Cycle of Angiosperms

sporophyte is dominant each flower produces both pollen and eggs the pollen is made in pollen chambers within anthers the ovule produces a megaspore which undergoes meiosis to produce four haploid cells three of the haploid cells die, leaving the last cell to produce the embryo sac (female gametophyte) by mitosis the stigma secretes a sticky substance that holds pollen the pollen will grow a pollen tube through the style into the ovule where it will undergo mitosis to form 2 sperm nuclei the sperm nuclei both fertilize the egg; this is called double fertilization the ovule will now grow into a seed which contains an embryo

Forming the Fruit after double fertilization has occurred, the ovary and ovule grow a fruit is a mature ovary a seed is a mature ovule Pollination transfer of pollen from an anther to a stigma is called pollination self-pollination is when, in some plant, pollen can fall from the anther to the stigma in the same flower usually cross-pollination occurs, which is when pollen is transferred from one flower to another How are seeds distributed? plants dont want their offspring right below them (too much competition) seeds may have sharp barbs to attach to an animal or it may provide food for the animal Why would unripe fruit be bitter? the seeds are not ready to be eaten yet; they have not stored enough nutrients Human Uses for Angiosperms 1) wood: eg. oak trees 2) food: leaves - spinach, lettuce stems - celery roots - potatoes flowers - broccoli, cauliflower seeds - peanuts 3) fibres: cotton, flax 4) chemicals: alcohol, vinegar, rubber, dyes 5) drugs: aspirin, morphine, caffeine 6) aesthetic purposes: ornamental plants and flowers, windbreakers Leaves provide a large surface for the plant to capture light for photosynthesis have specialized tissues which allow them to exchange gases with the atmosphere and obtain water starting with the top of the leaf, the tissue layers are: 1) Upper epidermis - for protection of the leaf 2) Palisade mesophyll layer - this layer is for photosynthesis cells are very close together and have many chloroplasts 3) Spongy mesophyll layer - main function is for gas exchange cells are further apart 4) Lower epidermis - main function is still protection has many holes called stomata each stomata has 2 guard cells on either side, which can close the hole 5) The leaf has vascular tissue travelling in veins. The veins go through the top half of the spongy mesophyll layer.

Xylem Phloem

Seeds baby plant inside a protective covering with stored food the zygote undergoes mitosis to form the embryo the endosperm serves as food for the developing embryo the seed will develop a hard waterproof covering over the outside Why is endosperm 3N? it allows the plant seed to steal nutrients from the adult plant easier

(2N) (N)

(3N) = seed (2N in total)

The Importance of Gas Exchange photosynthesis requires CO2 and needs to get rid of O2 to do this, the epidermis has holes called stomata even with cuticles, if the stomata was open all the time, the plant would lose too much water guard cells have the ability to close the stomata during the day, the palisade layer uses CO2 up ( ) when CO2 levels are low, the guard cells take up water and stand straight up, opening the stomata at night, photosynthesis stops, CO2 levels increase, and guard cells lose water the guard cells sag and close the stomata; water can no longer leave the plant Are stomata open during the day or night? Why does this not make sense for the plant? Stomata are open during the day because the plant needs to exchange gases (CO2 and O2) and collect sunlight for photosynthesis. This does not make sense for the plant because conditions are usually hottest and driest during the day, leading to more water evaporation from the leaves. Some desert plants have CAM photosynthesis, allowing them to collect and store CO2 during the night, so their stomata can remain closed during the day. Transpiration more than 99% of water entering a plants roots system move through stems and leaves and evaporates through stomata eg. corn loses more than 4 L of water per day most water moves by transpiration pull water is made of hydrogen and oxygen it is polar, which means that water molecules are attracted to one another transpiration pull is the pulling of a column of water as it moves into a leaf to replace water lost by evaporation or photosynthesis Review of Vascular Tissue (Xylem only) in Different Plants Ferns: tracheid cells Gymnosperms: tracheid cells Angiosperms: tracheid and vessel cells

Growing Plants Annuals: grow and die each year Biennials: live 2 years - 1st year they grow stems and roots; 2nd year they flower and die Perennials: anything that lives more than 2 years; most have woody tissue Hormones chemical messengers in the body allows communication between body parts important for multicellular organisms hormones can affect more than one organ at a time Auxin auxin is produced at the apical meristem in high concentrations high concentrations cause the apical meristem to elongate auxin inhibits the growth of auxiliary buds (controls branching so leaves do not grow too close together and compete for sunlight) auxin also makes plants grow towards the light light causes auxin to break down therefore there is no more auxin on the light side of the branch this makes the branch grow towards the sun, as the dark side, with more auxin, grows faster than the light side

Cytokinins move upwards through the plant from the roots, except in the case of fruits (diffuses along the branch, making it thicker to support the fruit) cause the stems to thicken and not elongate this causes the bottom of the tree to be thicker than the top opposite effect of auxin, including lateral bud growth Gibberellins isolated from fungi cause plants to grow tall quickly scientists thought it would be great for plant crops BUT the plants were too brittle and broke