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Kingdom Plantae. Characteristics: Eukaryotic, Multicellular, Cell Walls made of Cellulose, Autotrophic (photosynthetic using chlorophyll) . Adaptations for Survival. To get water: root hairs increase surface area mycorrhizae increase root surface (absorptive) area & hold water near roots
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Kingdom Plantae Characteristics: Eukaryotic, Multicellular, Cell Walls made of Cellulose, Autotrophic (photosynthetic using chlorophyll)
Adaptations for Survival • To get water: • root hairs increase surface area • mycorrhizae increase root surface (absorptive) area & hold water near roots • Vascular plants use xylem to transport water to stems & leaves • To conserve water: • Waxy coating (cuticle) • Guard cells close stomata when water is scare to reduce transpiration (water loss thru leaves)
Adaptations for Survival • To get sunlight: • Leaves are large, flat, and broad • Leaves arranged on stem • To exchange gases CO2 & O2 • Guard cells control opening & closing of stomata to maintain homeostasis of gases • (need CO2 for photosynthesis) • (need O2 for cellular respiration)
Adaptations for Survival • To get nutrients/minerals • Mycorrhizae help absorption • Nitrogen-fixing bacteria (genus Rhizobium) pull nitrogen from air so plants can use it • Phloem moves sugars from photosynthesis from leaves to roots
Sexual Reproduction • Sexual: alternation of generations – alternate between haploid (n) and diploid (2n) phases • Sporophyte phase – 2n, diploid; undergoes meiosis produces spores (n) • Gametophyte phase – n, haploid; produces gametes (male-sperm; female-eggs)
Asexual Reproduction:Mitosis **Allows for fast reproduction, but NO genetic variation = can fill an environment quickly, BUT if/when environment changes, they may not be able to adapt to survive From cuttings: • Cut potatoes into sections, each with an eye, new plant grows from cutting • From plantlets: • Cactuses produce clones, drop from mature plant to ground, take root • Strawberries grow new plants from roots • Horticulturists use graftings
Nonvascular plants: Mosses, Liverworts, Hornworts (aka Bryophytes) • Small, close to ground & water • Have NO vascular tissue (xylem & phloem) • can’t pull water up • Depend on • Diffusion to transport nutrients • Osmosis to transport water • Sperm swim to egg cells • Reproduction: alternation of generations http://dbs.umt.edu/courses/sci226/gifs/images/lab4/img3_large.jpg
Sporophyte phase http://www.teara.govt.nz/files/di10639enz.jpg Gametophyte phase
Vascular plants: Gymnosperms & Angiosperms • Have specialized tissue to transport water and nutrients • Xylem – transports water from roots to leaves • “xy” goes high • Phloem – transports nutrients (glucose) from leaves to roots • “phlo” goes low • Can grow tall – redwoods > 300 ft.
Gymnosperms(Coniferophyta) “naked” “seed” Seed produced on scales of female cones Male cones – pollen grains Female cones-ovule Wind pollinates Angiosperms(Anthophyta) “enclosed” “seed” Seed produced inside layer of protective tissue (ovary – fruit) Some flowers have both male & female parts Pollination by wind or animals (more effective than wind pollination) Co-evolution of animals & plants for pollination http://1.bp.blogspot.com http://ineedwax.com/PineConeGroup.jpg
Specialized tissues • Roots - anchor plants, prevent erosion, mutualistic relationships with fungus (mycorrhizae) & bacteria (nitrogen fixers); transport materials, store food • Stems – support, transport (xylem & phloem), defense system, produce leaves & flowers • Leaves – main photosynthetic organs – broad, flat; water conservation: guard cells; gas exchange Masters of Photosynthesis: Sunlight + CO2 + H2O O2 + C6H12O6
Plant growth • Meristems – grow forever • Unspecialized cells – mitosis makes new cells ready for differentiation • Found in places of rapid growth: stem & root tips apical meristem – grow at tip (apex)
Root cap protects apical meristem on root (tender cells); excretes slippery substance to allow root to ease through soil
Plant development (in angiosperms) • Flowers exist to bring gametes together & protect zygote and embryo • Male gametophyte-pollen Female: ovule Pollination Fertilization Zygote + Endosperm Embryo + Endosperm (seed) Germination Seedling Mature plant
Water Transport • Active transport proteins in root cells – transport ions of nutrients into root • Now water in root cells is less concentrated than outside (concentration gradient) – water moves into roots by osmosis • Root pressure (waterproof strip prevents backflow) pushes water up into plant • Xylem tissue transports water to leaves • Transpiration – water loss through leaves (pulls water up in plant)
Regulation: hormones • Hormone: chemical signals that affect growth, activity, development • To respond, must have receptors (proteins to which hormones bind) • Auxins – regulatory substances produced by tips of growing plant • Stimulation cell elongation & new root growth • Cells on shaded side with more auxin elongate – bend shoot toward light • Cytokinins – produce effects opposite of auxins http://image3.examiner.com/images
Hormones • Gibberellins – stimulates growth, promotes germination, may cause dramatic increases in size • Abscisic Acid – opposite effects of gibberellins • Ethylene gas – stimulates fruits to ripen; causes leaves to seal off and drop in autumn http://image3.examiner.com/images
Tropisms – how plants respond to stimuli • Phototropism – grow toward light • Gravitropism – stems grow away from ground, roots grow toward ground • Thigmotropism – respond to touch – vines, tendrils • Rapid response – sensitive plant (Mimosa pudica), Venus flytrap – close leaves by osmotic pressure changes
http://www.dwm.ks.edu.tw/bio/activelearner/36/images/ch36c2.jpghttp://www.dwm.ks.edu.tw/bio/activelearner/36/images/ch36c2.jpg
http://botit.botany.wisc.edu/images/130/Tropisms/gravitropism/Gravitropism_MC.jpghttp://botit.botany.wisc.edu/images/130/Tropisms/gravitropism/Gravitropism_MC.jpg
http://upload.wikimedia.org/wikipedia/commons/7/7d/Brunnichia_ovata_.jpghttp://upload.wikimedia.org/wikipedia/commons/7/7d/Brunnichia_ovata_.jpg
http://upload.wikimedia.org/wikipedia/commons/1/12/Mimosa_pudica_01_ies.jpghttp://upload.wikimedia.org/wikipedia/commons/1/12/Mimosa_pudica_01_ies.jpg