Unit 5 – Plant Anatomy, Growth & Function PLANT BIOLOGY: INTRO Unit 5 – Plant Anatomy, Growth & Function

PLANTS IN OUR SOCIETY In small groups, brainstorm uses for plants in OUR society.

USES FOR PLANTS IN OUR SOCIETY Fuel (ethanol from corn) Medicine (aloe vera, med. marijuana) Tools (wood, toxins in wood to kill fish, weapons) Food Construction Alcohol (potato  vodka; grapes  wine) To breathe! Shade Fragrances Composting Narcotics Clothing (ex. Hemp, cotton) Dyes, tattoos, henna Paper Soaps Flour, mint, herbs, tea, spices Make-up, cosmetics, beauty and skin care, jewellery

Important Crops in Canada (thousands of tonnes) Wheat 28, 611 Canola 12, 642 Barley 11, 781 Grain corn 10, 592

Food Security http://www.youtube.com/watch?v=PiYDG11zIUs

Monoculture One type of plant is grown in place of the natural ecosystem What are some pros and cons of this approach?

Learning Check Pg 539, Q 1-6

Medicinal Uses 25% of prescription medicines contain plant extracts Rosy periwinkle (vincristine andvinblastine) – childhood leukemia and Hodgkin’s. Survival rates have gone from 20% to 90% with these 2 compounds Goldenseal – colds and sore gums Ginseng – immune system function

Biofuels Most biofuels come from corn (ethanol). What are some pros and cons of this method? Research is being done to get fuel from cellulose and oil from algae http://www.youtube.com/watch?v=VI4Qm2AMiEY http://www.youtube.com/watch?v=n9_-ZguuhBw Read Quirks and Quarks on page 542

Erosion Control The paradox of farming: farmers need good soil to farm, yet farming destroys good soil. 2.5 million acres each year are lost to urbanization and soil erosion. About 1/3 of the country's topsoil has been lost due to urbanization and soil erosion.

Medicinal Plants Assignment Pg 573

KINGDOM PLANTAE Plants evolved about 500 million years ago from simple green algae that lived in the ocean. All plants are autotrophic and some, like the famous Venus fly-trap, can also be heterotrophic. All plants are eukaryotic and multicellular.

PLANT CELLS Like animal cells, plant cells contain a nucleus and organelles, but they have two distinguishing features: Cell wall (made of cellulose, a complex carbohydrate, provides rigid structural support; difficult to digest) Chloroplast (organelle that conducts photosynthesis) Animal cells have lysosomes that release the cellular equivalent of digestive enzymes. Why don’t plants need these?

PLEASE... CONSIDER THE FOLLOWING: How can plants stand up straight without a skeleton? 15

PLANT DIVERSITY Currently over 350 000 species of plants, including: Mosses Ferns Conifers Flowering plants Most plants live on land and can withstand a wide variety of climates. Cacti live in arid, dry areas whereas mosses need to be in moist environments to survive.

CLASSIFYING PLANTS Plants are classified based on the presence or absence of vascular tissue Vascular tissue can be compared to arteries and veins: a network of specialized cells that allows plants to transport water, minerals and sugar throughout the plant What would you expect a non-vascular plant, without vessels to transport nutrients and water, to look like?

Non-vascular (ex. moss) Vascular (ex. tree, sunflower) Plants Non-vascular (ex. moss) Cannot transport foot or water between plant parts Transport of fluid is through simple absorption or osmosis Must live in moist environments; need water for reproduction Vascular (ex. tree, sunflower) Contain a vascular system allowing for transportation of nutrients / water throughout the plant

WHAT MIGHT VASCULAR PLANTS LOOK LIKE?

FUNCTION OF STEMS Support system for plant body Transport system carries water & nutrients (through vascular tissue!) Holds leaves & branches upright Looking at the picture below: What years had the most rain? What years experienced the worst drought?

FUNCTION OF LEAVES Main photosynthetic organ Broad, flat surface increases surface area for light absorption Have systems to prevent water loss Stomata open in day but close at night or when hot to conserve water Waxy cuticle on surface System of gas exchange Allow CO2 in and O2 out of leaf Elephant Ear Plant

LEAF STRUCTURES Cuticle: waxy layer; covers upper surface Leaf Cross-Section Cuticle: waxy layer; covers upper surface Protects leaf against water loss Veins: transports water, nutrients and food Made of xylem and phloem vascular tissue Mesophyll: contains cells that perform photosynthesis b/c they contain chloroplasts. Cuticle Veins Mesophyll Stoma (Opening) 2 Guard Cells Surround each Stoma

LEAF STRUCTURES Guard cells: Cells that open and close the stoma Conserve water by preventing excess water transpiration Stomata: openings in leaf’s surface; when open: GAS EXCHANGE: Allows CO2 in & O2 out of leaf TRANSPIRATION: Allows excess H2O out of leaf Guard Cells Stoma

FUNCTION OF ROOTS Anchor & support plant in the ground Absorb water & minerals Hold soil in place Fibrous Roots Root Hairs

STRUCTURE OF ROOTS Root Hairs Root Hairs: increase surface area for water & mineral absorption Meristem: region where new cells are produced Root Cap: protects tip of growing root Meristem Root Cap

QUIZ TIME! BEFORE WE CONTINUE… VASCULAR OR NON-VASCULAR?

VASCULAR PLANTS http://dendro.cnre.vt.edu/forsite/idtype.htm Gymnosperms “Naked seeds” are not enclosed in an ovule (like a pine cone). Plants are usually evergreens. Ex. pines, cedars, spruces and firs. Angiosperms Mature seed is surrounded by the ovule (think of an apple). Angiosperms are trees/plants that shed leaves every autumn. Ex. Oaks, maples and dogwoods are examples of deciduous trees. Contain a vascular system allowing for transportation of nutrients / water throughout the plant http://dendro.cnre.vt.edu/forsite/idtype.htm

QUIZ TIME! BEFORE WE CONTINUE… GYMNOSPERM OR ANGIOSPERM ?

KEY WORDS: PLANT BIOLOGY Cell wall Chloroplast Vascular tissue Non-vascular tissue Stomata Cuticle Veins Mesophyll Chlorplast Guard cell Transpiration Root hair Meristem Root cap Gymnosperm Angiosperm