AP Plant Reading Guide Chapter 29: Plant Diversity I: The Colonization of Land 1. What adaptive features have contributed to the success of plants on land? Apical meristems, alternation of generations, walled spores produced in sporangia, multicellular gametangia, multicellular dependent embryos, cuticle (to prevent drying out and excessive water loss), secondary compounds (alkaloids, terpenes, tannins, phenolics-defend against predators, herbivores, parasites, absorb uv radiation), vascular system 2. Thoroughly understand the basic alteration of generation life cycle. A life cycle in which there is both a multicellular diploid form, the sporophyte, and and a multicellular haploid form, the gametophyte; characteristic of plants and some algae. terrestrial plants 3. What evidence supports the evolution of land plants from green algae called charophytes? Both have rose shaped complexes for cellulose synthesis, peroxisome enzymes, flagellated sperm, formation of a phragmoplast 4. What are the major features of the bryophytes? Lack vascular tissue!! Hornworts, liverworts, mosses. May have VERY simple tissue. 5. Describe the life cycle of the moss. Have long gametophyte stage.
Transcript
AP Plant Reading Guide
Chapter 29: Plant Diversity I: The Colonization of Land1. What adaptive features have contributed to the success of plants on land?
Apical meristems, alternation of generations, walled spores produced in sporangia, multicellular gametangia, multicellular dependent embryos, cuticle (to prevent drying out and excessive water loss), secondary compounds (alkaloids, terpenes, tannins, phenolics-defend against predators, herbivores, parasites, absorb uv radiation), vascular system
2. Thoroughly understand the basic alteration of generation life cycle.A life cycle in which there is both a multicellular diploid form, the sporophyte, and and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.
terrestrial plants3. What evidence supports the evolution of land plants from green algae called charophytes?
Both have rose shaped complexes for cellulose synthesis, peroxisome enzymes, flagellated sperm, formation of a phragmoplast
4. What are the major features of the bryophytes?Lack vascular tissue!! Hornworts, liverworts, mosses. May have VERY simple tissue.
5. Describe the life cycle of the moss. Have long gametophyte stage.
6. What are the major features of vascular plants?Have a xylem and a phloem.xylem=water and minerals, tracheids, have lignin. Phloem=sugar conducting. Have roots (anchor and absorption of water and nutrients), leaves (mirophyll or megaphyll). Have long sporophyte stage
7. What are the major features of the seedless vascular plants?Lack seeds- pterophytes (ferns and their relatives) and lycophytes (club mosses and their relatives)
8. Be very familiar with these life cycle terms: gametophyte, sporophyte, homosporous, heterosporous, megaspores, microspores- Gametophyte-multicellular haploid form that mitotically produces haploid gametes that unite and
grow into the sporophyte generation. Sporophyte multicellular diploid for the results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation. Homosporous plant species with a single type of spore, which typically develops into a bisexual gametophyte. Heterosporous plant species that has two types of spores, microspores that develop into male gametophytes and megaspores that develop into female gametophytes.
9. Describe the life cycle of the fern.
Chapter 30: Plant Diversity II: The Evolution of the Seed Plant1. What are the major features of seed plants?
Their tiny gametophytes can develop from spores retained within the sporangia of the parental sporophyte-protects delicate female (egg containing) gametophytes from environmental stresses-drought, UV radiation,dependent embryo gains nutrients from sporophyte. Ovules (houses eggs), pollen (sperm). Reduced gametophyte, heterospory, ovules, pollen.
2. Understand the 3 variations on the alternation of generation life cycle in plants.3. What are the major features of the gymnosperms?
5. What are the major features of angiosperms?Seeds contained in fruits, flower and fruit, monocot (one cotyledon, parallel veins, scattered vascular tissue, fibrous roots, petals in 3s, one pollen grain opening), eudicots (two cotyledons, netlike veins, ring shaped vascular tissue, taproot, petals in 4s or 5s, three pollen grain openings). Flowers and fruits=seed dispersal.
6. Describe the life cycle of the angiosperm. 7. What is co-evolution? Give an example.
Linked adaptations that involve reciprocal genetic change in two species. Madagascar- 11 inch nectar on orchid-only good for bird with 11 inch proboscis.
8. How have plants impacted humans?Products-crops, food, wood, medicines.
9. What is the adaptive significance of alternation of generations in the major groups of plants?
Chapter 35: Plant Structure and Growth1. Describe the structure and function of roots, stems
and leaves.ROOTS-anchor vascular plants, absorb minerals and water and store organic nutrients. Taproot (eudicot and gymnosperms)-one main vertical root from embryonic root-gives rise to lateral (branch) roots; fibrous root (seedless vascular and monocot)- a mat of thin roots spreading in soil; adventitious roost-roots in unusual locations. STEMS- vertical stems bear leaves and flowers in flowering plants, nodes
(where leaves are attached) and internodes (segments between nodes)-in ngle formed by each leaf=axillary bud(potential to form lateral shoot, dormant), terminal bud (shoot tip where elongation occurs) the proximity of the terminal bud is partly responsible for inhibiting the growth of axillary buds (apical dominance). LEAVES-photosynthetic organ of vascular plants- flat blade and stalk (petiole), veins (vascular tissue)
2. Describe the structure and function of the specific types of plant cells.Parenchyma- make up ground tissue, active living tissue, thin cell walls, primary cell walls only, softer parts of plants, pth of herbaceous plant, edible part of fruit, some are photosynthetic, some store important biological molecules-starch, oil droplets, water, other store plant hormones, resin or enzymes, can differentiate into other cell types-wound healing
Collenchymas- primarily make up ground tissue, simple plant tissue, main job-provide support in non woody plant organs, elongated and active at maturity, walls unevenly thickened, very thick in corners, lacks secondary cell walls, lignin is not uniformly distributed, usually appears as strands.
Schlerenchyma- have both primary and secondary cell walls, walls are thick, hardened with lignin, skeleton of the plant, not flexible-found in areas that are no longer elongating, often dead at maturity, two types of cells: sclereids (hard cells found in nuts, gritty part of pears) and fibers (long tapered cells found in patches or clumps; hemp) Water conducting cells of the xylem- composed of tracheids and vessel elements, nonliving conduits through which water flows-tracheids (long thin cells), vessel elements (generally wider and shorter)
Sugar conducting cells of the phloem- sieve tubes-missing organelles leave them hollow, companion cell-non conducting cells which connect sieve tubes, help to load the sieve tubes and supply them with protein.
3. Differentiate between primary and secondary growth.Primary growth-occurs at apical meristems and results in growth of roots and shoots (taller)- roots extend throughout soil and shoots increase exposure to light and CO2.
The root tip is covered by a root cap, which protects the apical meristem as the root pushes through the soil. Growth occurs just behind it, the three zones of cells (zone of cell division, zone of elongation, zone of maturation). The primary growth of roots produces the epidermis, ground tissue, and wascular tissue. Stele is vascular cylinder. The ground tissue fills the cortext, the region between the vascular cylinder and the epidermis. The innermost layer of the cortex is called the endodermis.
A shoot apical meristem is a dome shaped mass of dividing cells at the tip of the terminal bud. Gives rise to a repetition of internodes and leaf bearing nodes. In gymnosperms and most eudicots. The vascular tissue consists of vascular bundles that are arranged in a ring. In most monocot stems, the vascular bundles are scattered throughout the ground tissue.
Secondary growth- occurs at lateral meristems and results in growth of the vascular cambium and cork cambium(woody part of plant) (wider)
Secondary growth occurs in stems and roots of woody plants but rarely in leaves. The secondary plant body consists of tissues produced by the vascular cambium and the cork cambium. In transverse section, the vascular cambium appears as a ring, with regions of dividing cells called fusiform initials and ray initials. The initials increase the vascular cambium’s circumference and add secondary xylem to the inside and secondary phloem to the outside. As a tree or woody shrub ages, the older layers of secondary xylem, heartwood, no longer transports water and minerals. The outer layers, sapwood, transport materials thru xylem. CORK CAMBIUM AND PERIDERM cork cambium gives rise to secondary plant body’s protective covering, or periderm
ROOTS
SHOOT
(cork cambium plus layers of cork cells it produces). Bark= all tissues external to the vascular cambium, including secondary phloem and periderm.
4. How does the organization of cells, tissues, and organs determine structure and function in plant systems?
Dermal tissue: outer protective covering; consists of a single layer of cells (epidermis) in nonwoody plants; consists of protective tissue layers (periderm) in older regions of woody plants;epidermis has a waxy cuticle to help prevent water loss
Vascular tissue: carries out long-distance transport between roots and shoots 2 types: xylem – conveys water & dissolved minerals from roots to shoots phloem – transports organic nutrients from source to sink xylem & phloem are collectively called the stele in roots, the stele is a solid central cylinder in stems & leaves, the stele is divided into vascular bundles
Ground tissue: tissues that are neither dermal nor vascular; if located internal to vascular tissue it is called pith; if located external to vascular tissue it is called cortex
Leaf tissue organization: epidermis has pores called stomata flanked by two guard cells; ground tissue (mesophyll) between upper & lower epidermis; palisade – upper layer of elongated cells
spongy – lower layer of loosely arranged cells; vascular tissue (veins) enclosed by protective bundle sheath cells
Chapter 36: Transport in Plants1. How is water (xylem sap) transported within plants?
Once in plant, water experiences a pull from the top of the plant. The pull is transpiration. Results from the evaporation near the top of the plant through leaves, stem
Water lost through leaf stomata then water flows into xyem vessels to replace lost water. Water flows up the stem xylem to replace leaf water. Water from the root xylem replaces stem water. Water flows into roots to replace root xylem water-water is cohesive (stick to itself) and adhesive (stick to polar surfaces). Water potential of atmosphere is low compared to soil water moves from an area of high water potential to an area of low water potential.
2. How are water and minerals absorbed by roots?Roots strengthen the osmosis mechanism by actively pumping ions into their xylem cellsosmosis into the xylem as water follows solutes. Water accumulates and develops a high pressure ~+2Mpa, in the root (pressure exerted by the water vacuole pressing against the cell wall and the cell wall pushing back) forces water into the stem xylem=ROOT PRESSURE. Guttation, production of water at the tip of the plant usually at leaf edges bc of root pressure. Water flows from root cortex.
WATER ENTERS BY OSMOSIS [Hi] to [Lo]- After soil solution enters the roots, the extensive surface area of cortical cell membranes enhances uptake of water and selected minerals. The endodermis is the innermost layer of cells in the root cortex. It surrounds the vascular cylinder and is the last checkpoint for selective passage of minerals from the cortex into the vascular tissue. Water can cross cortex via the symplast or apoplast route-casparian strip limits apoplast route.
3. How is transpiration controlled?Stomata, flanked by guard cells, which control the diameter of the stoma by changing shape. Changes in turgor pressure that open and close the stomata result primarily from the reversible uptake and loss of potassium ions (goes in, open stomata) BC WATER IS LOST THRU STOMATA.
4. How is phloem sap translocated within plants?Sugar movement is driven by pressure flow hypothesis. In leaves, sugar is produced in the mesophyll cells. Active transport moves protons out of the sieve tube cells into the phloem companion cells. The protons move back into the sieve tube cells by cotransport along with sucrose from mesophyll. This causes a large local increase in solute concentration in the sieve tubes causing water from nearby xylem to rush into sieve tubes, causing increase in hydrostatic pressure, which forces sugars away from thei
entry site. Sugar from the phloem is actively pumped into cells that will convert it to starch for energy storage and or simply use it as an energy source. As sugar moves into the cells, water potential increases in the phloem sieve tubes, thus water follows the sugar into the cells by osmosis, goes back to xylem. SUGARSINK.
Chapter 37: Plant Nutrition 1. What are the general characteristics of good soil?
Loam-most fertile, ashesion and retention of water, diffusion of oxygen to roots.2. Why are nitrogen fixing bacteria essential to the environment?
Nitrogen fixing bacteria convert atmospheric N to nitrogenous materials that plants can absorb as a nitrogen source for organic synthesis. Plants require nitrogen as component of proteins, nucleic acids, chlorophyll, etc.
3. Compare and contrast root nodules and mycorrhizae.Along a legumes roots are selling called nodules, composed of plant cells “infected” by nitrogen fixing Rhizobium bacteria. These bacteria obtain sugar from the plant and supply the plant with fixed nitrogen. Different strains of bacteria=different legumes (beans).
Mycorrihizae are mutualistic associations of fungi and roots. Fungus benefits from a steady supply of sugar from the host plant. The host plant benefits bc the fungus increases the surface area for water uptake and mineral absorption. In ectomycorrhizaae, the mycelium of the fungus forms a dense sheath over the surface of the root. In endomycorrhizae microscopic fungal hyphae extend into root.
Chapter 38: Plant Reproduction and Development1. Describe the structures in a flower.
Flowers are the reproductive shoots of the angiosperm sporophyte.
• sepals (infertile) – enclose & protect the floral bud• petals (infertile) – attract pollinators• stamen (fertile) – made of a filament (stalk) & anther (site of
pollen production)• carpel (fertile) – consists of a stigma (pollen landing site), style,
& ovary (location of ovules)• all floral organs attached to the stem at the receptacle
2. Explain the development of fruits and seeds.Product of fertilization-pollen and egg- seeds and fruits. After landing on a receptive stigma, a pollen grain produces a pollen tube that extends between cells of the style towards the ovary. The pollen tube then discharges two sperm into the embryo sac. On sperm fertilizes the egg, resulting in the zygote (2N) and the other sperm combines with the polar nuclei giving rise to the food storing endosperm (3N). after double fertilization, each ovule develops into a seed. The ovary develops into a fruit enclosing the seeds. A fruit develops from the ovary and protects the enclosed seeds and aids in the seed dispersal by wind or animals.
3. What is the adaptive value of fruits and seeds?Can remain dormant for long periods of time, easy to disperse, breaking of dormancy requires environmental cues (temp and lighting). Radical (embryonic root) emerges first, nest shoot tip breaks through the soil surface. In eudicots, a hook forms in the hypocotyls and growth pushes the hook above ground.
Chapter 39: Control Systems in Plants1. What are the responses of plants to environmental cues and how do hormones mediate them?
•plant hormones control plant growth and development by affecting the division, elongation, & differentiation of cells
•some hormones also mediate short-term physiological responses of plants to environmental stimuli•each hormone has multiple effects depending on its site of action, its concentration, & the developmental stage of the plant
•hormones may act by altering the expression of genes, affecting the activity of enzymes, or by changing membrane properties
•signal transduction pathways amplify hormone signals•responses are often governed by the interaction of two or more hormones
2. Specifically, what are the effects of the following hormones on plants: auxin, cytokinins, gibberellins, abscisic acid, ethylene?
3. Specifically, what is phototropism, gravitropism, thigmotropism?• phototropism = growth response to light
o shoots exhibit positive phototropism = growth towards lighto roots exhibit negative phototropism = growth away from light
• asymmetrical distribution of auxin moving down from the shoot tip causes cells on the darker side to elongate faster than cells on the brighter side
• gravitropism=plant growth in response to gravityo roots exhibit positive gravitropism o shoots exhibit negative gravitropism o auxin plays a key role in gravitropism by affecting cell elongationo gravity detection may be due to the settling of plastids containing dense starch grains (statoliths)
to the lower sides of cells • thigmotropism= refers to the changes in form that result from mechanical perturbation (ie: touch)• thigmotropism = directional growth in response to touch• growth may be inhibited by touch (plants grow shorter, leaves shrivel in)-can be restored in some cases.
4. How do phototropism and phytochromes control flowering?• Photomorphogenesis-refers to effects of light on plant morphology
– plants have two major classes of light receptors for detecting light:– blue-light photoreceptors
• important in phototropism, light-induced stomata opening, light-induced slowing of hypocotyl elongation that occurs when a seedling breaks ground
– phytochromes • important in seed germination, shade avoidance, flowering
• Phytochromes-– alternate between two forms:
• Pr absorbs red light (660 nm) & is converted to Pfr
• Pfr absorbs far-red light (730 nm) & is converted to Pr
