Plants

Vascular Plants

Vascular Plants

Have vascular vessels to transport water & food

Non-Vascular Plant

Small simple plants, no vascular system. Cannot transport food/water far. No roots, have rhizoids. Found in moist environments. Reproduce sexually via spores or asexually via vegetative propagation

Rhizoids

Small hairs that keep non vascular plants in place

Non-Vascular Plants examples

Mosses, liverworts, hornworts

Plants with seeds

Allow plants to sexually reproduce without water, provide protection.

Seed Plant Evolution

Climate colder and drier so spore producing plants could not survive.

Seedless plants

dont produce seeds, disperesed via windblown seeds or water. Formed first forests.

Seedless plants examples

Ferns, whisk ferns, club mosses, horsetails

Angiosperms

Flower producing plants. Mature seed surrounded by ovule, referred to as hardwoods.

Gymnosperms

Seeds not enclosed in ovule, no flowers, softwoods.

Ginkgo Biloba

Only living species in division Ginkgophyta, all others extinct. Member of very old genus, some fossils dating back 200 million years.

Cycads

Seed plants with a very long fossil history, formerly more abundant and diverse.

Seed Parts

Embryo, Endosperm, Seed Coat

Embryo

Young multicellular organism before it emerges from seed

Endosperm

Source of stored food (mostly starches)

Seed Coat

1 or more protective layers that encase seed

Cotyledon

Embryonic leaf in seed-bearing plants, first leaves to appear in germinating seed.

Dicot seed

2 cotyledons, cotyledons fleshy and store food, endosperm absent.

Monocot seed

1 cotyledon, thin, small and lacks food materials. Endosperm present, stores food.

Stems made up of…

Nodes (Hold leaves and buds which grow into branches) and Internodes (spaces between the nodes)

Stem functions

Support for leaves, flowers, fruits. Transport of fluids. Storage of nutrients. Production of new living tissue.

Normal life span of plants

1-3 years

Meristems generate

new living tissue

Tissues in the stem

Dermal, Ground, Vascular

Dermal Tissue Stem

Outer surface, waterproofs, protects, and controls gas exchange.

Ground Tissue Stem

Mainly parenchyma cells that perform photosynthesis. Functions as storage/support.

Vascular Tissue Stem

Provides long distance transport, structural support.

Herbaceous Dicot Stems

Stems with primary growth. Pith in the centre, vascular bundles in distinct outer ring, epidermis/cuticle protects outside. Usually dont grow very tall.

Primary Growth

Growth that occurs as a result of cell division at the tips of stems and roots

Woody Dicot Stems

Secondary growth causes stems to thicken, not elongate. Vascular cambium cells divide to produce secondary xylem on inside and secondary phloem on outside. As stem diameter increases, cortex & epidermis destroyed and cork cambium develops, producing cork cells. Secondary xylem stops transporting materials, becomes structural support (what we commonly call wood).

Tree rings

At the end of each growing season, vascular cambium stops growing - creating a growth ring.

Tree Ring Seasons

In the spring, lots of xylem produced, cells are larger and wood less dense. In fall, fewer and smaller xylems produced and wood very dense.

Monocot stems

Vascular bundles scattered throughout. Rarely produce secondary growth, seldom woody.

Xylem Cells

Tracheids and vessel elements. Thick walled, dead and maturity, rich in lignin (carbohydrate for strong cells).

Phloem Cells

Sieve tubes and Companion Cells. Living at maturity, contain cytoplasm.

Tracheids

Long, cylindrical cells with tapered ends. Cell walls have pits that allow water/solutes to pass up/across to neighboring xylem.

Vessel Elements

Short/wide cells with less tapered ends. Only side cell walls have pits. Other walls have perforation plates (end walls with one of more openings to allow water an solutes to pass through connected tube they form.

Sieve Tube Elements

Have cytoplasm, lack many cell organelles, including a nucleus. End walls of these cells called sieve plates (Cell walls with perforations to allow sugar solutions to pass to neighboring phloem cells).

Companion Cells

Always with sieve tube elements (Has nucleus/Other organelles that sieve tube element lacks).

Root Functions

Anchors, Absorption, Transportation, Storage

Root Structure Parts (Specialized)

Meristem, Root Cap, Root Hairs

Meristem

Unspecialized cells that divide and differentiate into specialized tissues

Root Cap

Cells produce mucus-like substance which lubricates movement of root through soil

Root Hairs

Increase surface area for absorption of nutrients and water

Root Layers

epidermis, Cortex, Vascular cyliner

Epidermis Roots

Root Hairs increase absorption of water and minerals

Cortex

Transports water & minerals from epidermis to vascular cylinder
Storage of food
Endodermis is the inner waxy layer

Vascular Cylinder (Root)

Xylem transports water/minerals from roots to leaves
Phloems transports sugars from leaves to roots

Root Types

Taproots, Fibrous, Adventitious

Adventitious roots

Arise from organ other than root, usually stem.

Root Hairs (Describe Absorption)

Root cells usually hypertonic to soil, so water enters passively by osmosis. Walls of root cells very thin, have a large surface area.

Depth of the root..

Depends on the moisture content of the soil

Hypertonic

Has a greater concentration of solute relative to an adjacent solution

Monocot Roots

Fibrous roots, separate strands of xylem and phloem alternate around a pith-like region.

Dicot Roots

Taproots, Xylem x-shaped and a solid strand, phloem arranged in separate strands.

Casparian Strip

Waxy layer that coats endodermal cells, prevents water from moving in the spaces between the endodermal cells

Leaves function

Photosynthesis (Uses carbon dioxide, produces oxygen and glucose)

Leaf Structure

Designed to capture maximum light, minimize water loss

Leaf Tissues

Dermal, Ground, Vascular

Dermal Tissues in Leaf

Epidermis, Stomata & Guard Cells

Leaf Epidermis

Outer protective layer of polygonal cells, defends against injury and invasion by foreign organisms.
Secretes waxy substance that forms a coating (cuticle) on the surface of the leaf.

Cuticle

Waxy surface coating substance secreted by epidermis, unique to terrestrial plants, allows them to retain water.

Stomata & Guard Cells

On leaf’s lower epidermis there are microscopic pores known as stomata. Each is a small opening between pair of specialized guard cells.

Opening and Closing Stomata

Guard cells open and close stomata to regulate gas exchange and transpiration. When high solute, water moves into guard cells, they swell and open stomata. Low solute, water moves out, close.

Day and Night in Stomata

Open during the day, closed during the night.

Opening and Closing of Stomata Environmental Factors

When weather hot and dry, guard cells of plant close stomata in order to reduce evaporation from leaf stomata.

Vasular Tissues Leaves

Transports reactants and products of photosynthesis. Xylem and phloem from stem divide into two branches to supply materials. Make up the veins. These components extend through the mesophyll so they are in close proximity with photosynthesis tissues.

Ground Tissue LEaf

Found in mesophyll of leaf (between epidermal layers). Predominant cells are parenchyma cells, which contain chloroplasts (sites of photosynthesis).

Mesophyll Regions

Upper section, the palisade parenchyma. Lower section, the spongy parnechyma.

Palisade Parenchyma

Elongated columnar parenchyma cells, contain 3 - 5x more chloroplasts than spongy.

Spongy Parenchyma Cells

Irregularly shaped, allowing gases to circulate through the air spaces between to the palisade parenchyma

Dicot Leaf

Stomata guarded by kidney shaped guards, branched veins, two types of mesophyll.

Monocot leaf

Stomata guarded by dumbbell shaped guards, parallel veins, no mesophyll differentiation.

Photosynthesis stages

Light Reactions, Calvin Cycle

Light Reactions

Takes place within thylakoid membrane (tiny compartment in chlorplast). Uses solar energy to split water into hydrogen ions, eletrons and oxygen. Excites electrons within chlorophyll that sets off a series of reactions which create high energy compounds.

Calvin Cycle

Takes place within stoma of chloroplasts. Uses high energy compounds from light reactions to drive cycle. Carbon dioxide combines with intermediate compounds to form glucose.

Photosynthesis Word Equation

Water + Carbon Dioxide → (Sunlight) Glucose + Oxygen

Photosynthesis Requirements

Water, Carbon Dioxide, Sunlight

Photosynthesis Purpose

Ceates food (sugars from chloroplasts) that plants use to fuel cellular respiration (Used in mitochondria to create energy in the form of ATP)

Macronutrients

Nitrogen, Phosphorus, Potassium, Calcium, Magnesium

Nitrogen

Component of proteins, DNA & RNA

Phosphorus

Component of DNA & RNA

Potassium

Controls stomata, water intake

Calcium

Development and function of cell walls

Magnesium

Component of chlorophyll

Micronutrients

Iron, Zinc, Copper

Iron

Chlorophyll structure, cell respiration

Zinc

Regulation of plant growth, function of chloroplasts

Copper

Reproduction, Root metabolism, cell respiration

Organic Fertilizers

From living sources

Inorganic Fertilizers

Produced chemically

Plant Fertilizer Percentage

10-18-10 of N-P-K

Role of macronutrients in Fertilizer

N promotes green growth
P promotes root and flower growth
K promotes hardiness

Fritz Haber

German chemist, received nobel prize in chemistry for invention of haber-bosch process. Method used in industry to synthesize ammonia from nitrogen gas and hydrogen gas. Important for large-scale synthesis of fertilizers and explosivrs

Seeds require _ for germination

heat and moisture

Seed Germination Hormone

Giberellin hormone released, starch broken into simple sugars to provide energy for growing embryo

Seed Germination Oxygen & Water

Water absorbed into seed, seed coat cracks
Oxygen diffuses into seed for cell respiration

Seed Germination Steps

1. Gibberellin hormone released

2. Water absorbed into seed, seed coat cracks

3. Oxygen diffuses into seed for Cell Respiration

4. Radicle emerges, pushes down and becomes root

5. Hypocotyl emerges, pushes up to become stem

6. Epicotyl and Cotelydons grow upward to form leaves

7. True leaves develop, plant matures

Water Transport

Root hairs absorb minerals via active transport (glucose stored in roots produce energy via CR)
Minerals Actively pumped from soil water into epidermis → cortex → endodermis → xylem
Sets up hypertonic condition → water rushes in passively via osmosis
Root Pressure pushes water & minerals up xylem

Leaf Pull

Evaporation of water “pulls” on adjacent water molecules, move up the stem via adhesion and cohesion