BOT 200 Dr. Meiers Chapter 5 lecture notes
BOT 200 Dr. Meiers Chapter 5 lecture notes 200
Popular in Introduction to Botany
Popular in Botany
This 4 page Class Notes was uploaded by Keely Egelhoff on Saturday September 24, 2016. The Class Notes belongs to 200 at Western Illinois University taught by Dr. Meiers in Fall 2016. Since its upload, it has received 13 views. For similar materials see Introduction to Botany in Botany at Western Illinois University.
Reviews for BOT 200 Dr. Meiers Chapter 5 lecture notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/24/16
Chapter 5 Lecture Notes Tissues and 1° growth of stems Basic types of cells and tissues - Stems and leaves and roots all share a basic simple organization - All plant cells belong to just 3 classes based on the nature of their cell walls 1. Parenchyma 2. Collenchyma 3. Sclerenchyma Parenchyma - only 1° walls alive when mature - form parenchyma tissue - metabolically diverse - special parenchyma 1. chlorenchyma 2. glandular cells 3. transfer cells 4. phloem Specialized Parenchyma - Parenchyma cells are (PSN) thin walls allow light and gas exchange to chloroplasts - Glandular cells 1. Secrete: 2. Nectar 3. Fragrances 4. Mucilage 5. Resins 6. Oils - Phloem- parenchyma tissue that conducts nutrients over long distances - Some parenchyma cells function by dying at maturity to open areas - Parenchyma cells are relatively inexpensive to build, quick growth diverse functions Collenchyma - Collenchyma cells have a then 1 ° wall that becomes thickened in corners, flexible yet strong cells usually located: 1. Beneath epidermis 2. Supporting vascular bundles Sclerenchyma - Scletenchyma have 1° and a thick 2° wall (dead @ maturity) sclerenchyma supports the plant - Two types: 1. Conductive 2. Mechanical Mechanical sclerenchyma - Fibers are long and flexible - Sclereids are short is odiametric (enboidal) inflexible, brittle - Conducting sclerenchyma transports water-treachery elements of the xylem - Possess regions of plasodesmata- rich connections to surrounding cell pits Stem Basics - Stem region between leaves and roots of vascular plants functions: 1. Elevate leaves (for PSN) 2. Transport H O2 sugars, hormones, molecules around thallus 3. Produce flowers and fruits 4. (maybe) storage (ex: potatoes, etc.) 5. Produce hormones for thallus - Modifications increase stems ability to survive, transport or store nutrients - Decreases its efficiency at other tasks “balancing act” - Buds not apical remain dormant or produce flowers - Most plants axillary buds not needed if apical meristem is health if damaged/killed axillary buds become active/develop Internal stem organization arrangement of 1° tissues - Epidermis: outermost surface of herbaceous stem single layer of parenchyma cells - Exchange of material between plant and environment occurs via epidermis - Functions: 1. Protection 2. Prevent H O2loss - Epidermis coated with water proof cutin layer called cuticle - Cuticle prevents gas exchange so accomplished by stomata - Stomata: pairs of guard cells surrounding stomatal pore - Guard cells swell when absorbing H O 2 - Pore opens allow exchanged CO and O2 2 - Water lost through stomata balances open/closed with H2O needs/ gas exchange - Some epidermal cells develop into trichrome (hair) - Protect against animal attack/ H O 2oss/too intense sunlight - May produce oil and anitiherbivore/microbial chemicals (chemicals) 1. Poison ivy/oak Vascular tissues - 2 types 1. Xylem- conducts H O a2d mineral up thallus 2. Phloem: distributes sugars and minerals up and down - Xylem dead and hollow at maturity 2° cell wall - Phloem alive at maturity transports dissolved materials 1° cell wall only Xylem - Tracheid and or vessel elements - Types of sclerenchyma and treachery elements simplest form 2° cell wall organized as set of annular thickenings on inside of 1° cell wall - Parenchyma specializes/ forms 2° cell wall dies - Carious patterns of 2° cell wall inside 1ׄ° cell wall- provides strengthening and support to vascular bundle region - Perforations form between vertically stacked vessel elements - Stack of vessel elements - Angiosperms have tracheid and vessel Need elements - Gymnosperms have only tracheid to know - Tracheid are the ancient form of xylem/phloem Phloem - 2 types of connection cells 1. Sieve cells 2. Sieve tube members - Term sieve elements refers to either - Live parenchyma cells at maturity 1° cell wall only - Plasmodesmata enlarge to become sieve pores aggregate in sieve areas Sieve cells - Elongate - Spindle shaped - Sieve areas distributed over surface - Gymnosperm and angiosperm - Sieve tube members - Wider sieve areas on each end wall called sieve plates align vertically form sieve tubes - Nuclei of sieve elements degenerate - Associated with neighboring cells that exert nuclear control - End walls develop open areas sieve areas sieve tube members (A) association with companion cells - Can get rid of nucleus if another companion cell takes over - Sieve cells (G,A) association with albuminous cells - Albuminous and companion cells not the same thing through do similar things - Companion cells: smaller prominent nucleus and dense cytoplasm - Has to produce and control both cells - Control sieve tube member - Load molecules into sieve tube member Vascular bundles - Xylem and phloem occur together in vascular bundles interior to cortex - In stems leaves flowers - Eudicots- vascular bundles arranged in one ring surrounding pith central region of parenchyma similar to cortex - Monocots: distributed throughout inner part of stem - All vascular bundles collateral: each contains xylem and phloem stands running parallel to each other - Xylem of vascular bundle: primary xylem - Phloem of vascular bundle: primary phloem - Both: part of 1° plant body - Frequently associated with fibers (strength) or parenchyma (short turn storage) Stem growth and differentiation - Stems grow longer by creating new cells at tips in apical meristems - Cells continuously divide/remain mitotic - As smaller daughter cells expand and grow push meristem increases - Region below apical meristem: subapical meristem - Cells also dividing and growing slower rate - Some cells here stop dividing and differentiate into protoxylem (early xylem) cells - Cells exterior to protoxylem then differentiate - Larger because they have been expanding longer= metaxylem (middle xylem) - Similar process occurs outer part of each vascular bundles - Exterior cells mature: protophloem - Cells closest to protophleom become metaphloem - Other tissues also differentiate in subapical region: epidermis pith cortex - But xylem first
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'