Botany Lab Practical 1 Notes

-Greenhouses/conservatories: Allow for plant growth throughout the year and control of various aspects of the environment, including temperature, humidity, amount of light, and amount of water.

-Growth Chamber: For more environmental control, especially for physiological control. Like wavelength, CO2 in their atmosphere.

-Botanical Gardens: Long-lived plants can be kept and observed outside.

-Arboretum: Garden of trees

-Herbarium (plural: herbaria): Museum of dried specimens

-Compound Microscope: Uses 2 lenses “stacked” to multiply magnification, powerful, sensitive, viewing issues = image reversal, limited depth to focus, limited field of view.

-Dissecting Microscope: Two separate lenses create binocular vision, low power, easy to use.

-Magnification:

-Resolution: The level of detail of an image, typically the least distance between two points where they appear separate, rather than a single blurred object.

-Image Reversal: The image seen through the compound microscope appears upside down and backward. When the microscope slide is moved to the left, the image moves to the right.

-Field of View: The area that can be seen by a person or optical device, typically decreases as magnification increases. Low magnification = wider field of view, higher magnification = narrower field of view.

-Depth of focus: Limited depth of focus; to see all levels within a typical plant cell the focal setting of the microscope must be changed.

-Through-focusing: Focus up and down through the object on the slide to get a complete view of the cell. The goal is to have a three-dimensional concept of the cell.

-Working Distance:

-Parfocal:

-Microscope Slide:

-Cover Slip:

-Prepared Slide:

-Microtome:

-Section:

-Wet-mount Preparation:

-Light Microscope:

-Electron Microscope:

-Total Magnification: Ocular Lens Magnification x Objective Lens Magnification = Total Magnification

-Planes of Section: Transverse, longitudinal, and paradermal section.

-Microtome: Extremely sharp blade used to make very thin sections of prescribed and uniform thickness.

-Transverse/Cross Section: Across the long axis

-Longitudinal Section: Parallel to the long axis, two types: radial and tangential

-Paradermal Section: Across and parallel to the epidermis.

-Stats: Science of extracting meaning from raw data takes in consideration sample size and variation within the samples.

-T-test: Useful for separating meaningful inferences from “noise”.

-Parenchyma: Thin, uniform cell wall, ‘filler’ in soft plant

-Collenchyma: Irregularly thickened cell walls, gives the plants flexibility/elasticity + some strength, restricted to subepidermal plant posts.

-Sclerenchyma: Dead structered cells, heavily thickened secondary cell walls, usually in non-growing areas of a plant, two types: sclereids and fibres

-Longleaf Pine (Pinus palustris): long needles, needles look like fireworks, big cones, “grass stage” with deep roots, needles are fire resistant.

-Loblolly Pine (Pinus taeda): Most common, widely planted for lumber bc grows fast, environmental tolerant, not fire repellant, hand size needles, sharp prickles on cones, grey color

-Shortleaf Pine (Pinus echinata): Drier, upland sites, needles very short (>3.5 inches)/palm size, small cones (>2 inches)

-Urushiol: Mixture of resins/oils that can allergic reaction of the skin.

-Poison Ivy (Toxicodendron radicans): Most common poisonous plant. Can grow as a vine, woody vine, or shrub. Three parted leaves alternate on the stem, often shiny dark green, and several teeth. In the fall, turn a red color.

-Poison Oak (Toxicodendron pubescens): Common species in dry, upland habitats. Small shrub growing, leaves similar to those of poison ivy. Plant is somewhat hairy, therefore has a duller, yellow-green color and its leaf teeth are rounded.

-Poison Sumac (Toxicodendron vernix): Most toxic plant in the U.S., is a shrub (1-3 m tall), and has compound leaves with 7-13 leaflets. Red color. Most commonly found in moist to wet areas. Mostly smooth edges/margins.

-Mixed Pine-Oak Hickory Upland: Canopy, spaced out, not much ferns + blooming flowers, organic matter on the floor/fungi, SQUIRRELS!!!!

-Spring-Seeps: Gravel and sand deposits with clay underneath, gray-looking soil, snakes, more shrubs, ferns, pink moss, grass

-Freshwater Wetlands: Not a lot of trees (lack of moving water/O2), plants on top of water (openings on top)

-Longleaf Pine Savannah: Grasses, pine forests, flowers, butterflies, second-growth forest, and open canopy.

-Eukaryotes: Have membrane-bound organelles and a definite nucleus. Consists of the animal, plant, and protist kingdom.

-Protist is a polyphyletic grouping

-There are two groups of protists: algae (photosynthetic/autotrophic protists), protozoa (heterotrophic protists)

-Monophyletic: A group that includes all the descendants of a common ancestor

-Paraphyletic: A group that includes some, but not all of the descendants of a common ancestor.

-Polyphyletic: A group that is derived from more than one common ancestor.

-If algae is suspended in water, what is it referred as? Phytoplankton

-Phycology: Study of algae

-Euglenophyta/Euglenas: Photosynthetic, acquired photosynthetic abilities from endosymbiosis with green algae. Unicellular, flagellated, has an ‘eye spot’. Is not a plant because it has no cell wall, has no pigments, and no starch.

-Phaeophyta/Brown Algae: Multicellular algae, acquired chloroplasts from endosymbiosis from red or green algae. Most common in cool marine waters. Sargassum. Is not a plant because it doesn’t use starch, it uses laminarin instead, uses different pigments, fucoxanthin and chlorophyll A and C.

-Bacillariophyta/Diatoms: Unicellular, siliceous cell walls, occupies a wide range of habitats, gained the ability to photosynthesize from both green and red algae. Is not a plant because it has no pigments, no starch, and cellulose only present in some cell walls.

-Dinophyta/Dinoflagellates: Unicellular, possess two flagella, many are photosynthetic, but some are heterotrophic; some mixotrophic. Uses starch. Not a plant because some have cellulose and has no photo pigments (if it is present, its mainly peridinin, chlorophyll a and c, and carotenoids.

-Rhodophyta/Red Algae: Oldest groups of algae. Mostly multicellular. Does use cellulose. Is not a plant because it uses a special starch called Floridean starch, uses chlorophyll a, phycobilins, and carotenoids.

-Chlorophyta/Chorophyta/Green Algae: Earliest “true plants”. Can be unicellular, multicellular, or colonial. Mostly freshwater, can occur in marine and terrestrial. It’s a plant because it uses chlorophyll A and B, carotenoids, does have starch, and does have cellulose.

-What Makes a Plant: Storage of glucose in the form of starch, cell walls primarily composed of cellulose, and use of chlorophyll A and B.

BRYOPHYTES AND HOMO. LYCOPODS

-The first land plants: Lived near water, most likely liverwort-like, appeared in the Ordovician; about 460 million years ago.

-Aquatic Environment for Plants: Water, gas, and nutrients exchange through simple diffusion, no need for complex reproductive structures, and gravity has little effect.

-Terrestrial Environment for Plants: Water, gases, and nutrients not available through simple diffusion, reproductive structures increasingly get more complex the further away from water, and gravity has an effect. Greater access to light, more CO2 available, and for the time, less competition for resources. However, the downsides were avoiding desiccation, gas exchange, how to reproduce, and how to transport nutrients/minerals.

-Alternation of Generations: The basic life cycle for all terrestrial plants, two stages: gametophytes (makes gametes), sporophytes (makes spores).

-In the bryophytes, the gametophyte is the dominant life stage.

-In all other modern plants, the sporophyte is the dominant life stage.

-Bryophytes: Includes three phyla, lacks specialized vascular tissue, gametophyte is the dominant life stage, water is required for fertilization, doesn’t make seeds; reproduces using spores.

1. Anthoceratophyta (hornworts)

2. Marchantiophyta (liverworts)

3. Bryophyta (true mosses)

-Anthoceratophyta (hornworts): Sporophyte, tall, thin

-Marchantiophyta (liverworts): Mostly thalloid (leafy like), thallus (undifferentiated body plan), reproduction is both asexual (gemmae cups) and sexual (antheridia = male, archegonia = female), structures are pores (do not close) open to air chambers below epidermis and rhizoids (root-like structures that help absorb water efficiently).

-Gemmae Cups: Cup-shaped, easily detachable, gemmae (clones) splash out of the cups and grow (by mitosis) into new liverworts.

-Bryophyta (true mosses): Simple leaves that are only 1 cell thick, absorbs water/nutrients through leaves.

-Phylum Lycopodiophyta/Lycophytes: Carboniferous period, most are nonvascular and seedless, vascular plants produce only one type of spore (homospory), some are capable of generating two different spores (heterospory). Sporophyte is the dominant generation. Well-developed vascular tissue with lignin; each leaf in group (microphyll) has one unbranching vein. Includes three families:

1. Lycopodiaceae

2. Selaginellaceae*

3. Isoetaceae*

* = Heterosporous lycophytes

-Lycopodiaceae: Club mosses (not an actual moss), spores are extremely flammable, likes wetter areas but can tolerate drought, and homosporous

-Heterosporous Life Cycle: Sporophyte makes two different spores via two different structures on a spore-bearing structure called sporophyll (microsporophyll or megasporophyll) Resulting gametophytes from the different sporangia/spores produce either antheridia or archegonia.

-Microphyll/Megaphyll: regular leaf

-Sporophyll: Spore-making structure (usually a modified leaf-like structure), comes in either mega- or micro-

-Selaginellaceae: Spike mosses, heterosporous, are found worldwide, some can desiccate completely (resurrection moss).

-Isoetaceae/Quillworts: Heterosporous, if present they will inhabit floodplains and backwater streams plus temporarily flooded areas.

FERNS AND GYMNOSPERMS

-Equisetophyta/Horsetails/Scouring Rushes: Homosporous, have a cone like structure called a strobilus, high in silica

-Polypodiophyta: “Modern” ferns, most are homosporous, select few are heterosporous, sori and indusia key features.

-Sori (Singular = Sorus): Clusters in sporangia, typically on the underside of the leaves, some ferns have modified, non-photosynthetic leaves exclusively sori

-Indusia (Singular = Indusium): An umbrella-shaped structure that covers the sori, some have false indusia.

-Epiphytic: grows on other plants, not a parasite. Resurrection Fern (Pleopeltis polypodioides) is an example.

-Southern Shield Fern (Pelazoneuron kunthii): Most common fern in southern Mississippi.

-Gymnosperms: All are heterosporous, exhibits secondary growth (woody tissue), male microgametophyte is highly reduced pollen grain. 4 Lineages.

1. Ginkgophyta

2. Cycadophyta

3. Coniferophyta

4. Gnetophyta

-Gymnosperm Reproduction: all are heterosporous, microspores and megaspores are produced in pollen and ovulate cones respectively, microgametophytes (male) are highly reduced to pollen grains, megagametophytes are retained in the ovule.

-Ginkgophyta: Only one species (Ginkgo biloba), native to small part of China, has distinct dichotomously veined/Y-branching leaves.

-Cycadophyta: Mostly tropical, dioecious (male and female reproductive structures found on separate individuals), pinnate, palm-like leaves.

-Coniferophyta: Includes pines, cedars, cypresses, etc., leaves needle-like or scale-like, both male and female cones grow on the same individual (monoecious)

-Gnetophyta: Only three genera; Ephedra, Welwitschia, and Gnetum

-Gymnosperm Wood Anatomy: No large vessels, all vessels are uniform, xylem tissue is made of tracheids (move materials vertically) and rays (move materials laterally).