Plant Biology: Photosynthesis and Adaptations

• Plants Definition

Photosynthesis

• Plants use the energy from sunlight to carry out photosynthesis
• Photosynthesis is the process plants use to convert light, carbon dioxide, and water into carbohydrates.
• The equation: 6H2O + 6CO2 + Sunlight yields C6H12O6 (Carbohydrate) + 6O2

Plant Adaptations for Sunlight

• Shape adaptations are based on gathering sunlight to outcompete others.
• Examples are:
  • Gas Exchange
    • Plants require carbon dioxide (CO2) to perform photosynthesis.
    • Plants need oxygen (O2) for cellular respiration and breathe out the excess oxygen.
  • Water
    • It is necessary to carry out photosynthesis
  • Minerals -Absorbed from the soil
  • Transport Structures
    • Developed to distribute water and minerals throughout the plant

Plant History

• Photosynthetic prokaryotes (Cyanobacteria) added oxygen to the atmosphere, which provided food for consumers
• The fossil record indicates plant ancestors were similar to green algae
• New ecosystems developed when plants appeared on land
• The following plants developed from the pioneering land plants:
  • Bryophytes (Non-Vascular Plants)
  • Seedless Vascular Plants (Fern)
  • Gymnosperms (Cone-bearing plants)
  • Angiosperms (Flowering plants)
• Plants produce raw materials for:
  • Homes (wood)
  • Clothes (fiber)
  • Powerful and effective medicines

Taxonomy

• The science classifies organisms
• All plants have some things in common, including:
  • Being Eukaryotic
  • Having cell walls
• Plants are divided into 5 groups with 4 common features:
  • Embryo Formation to protect from harsh elements on land
  • Specialized water-conducting tissue assists to draw water to greater heights
  • Seeds provide food and protections while drying out
  • Flowers give reproductive advantages and become fruits

Alternation of Generations

• Life cycles of plants include 2 alternating phases:
  • Sporophyte is the Multicellular Diploid (2N) stage
    • Produces spores through Meiosis
  • Gametophyte: is the Multicellular Haploid (N) stage
    • Produces gametes that will undergo Fertilization to create a Zygote.

Trends in Plant Evolution

• There is a reduction in the size of the gametophyte with an increase in the size of the sporophyte

About Green Algae

• Algae are not one single group of organisms
• They below to the Plant kingdom
• Most of them are aquatic
• They can be found in fresh water and salt water
• Lack specialized tissue to absorb moisture
• Some form colonies, which provide hints as to how multicellular organisms evolved from unicellular ones.
• They undergo Asexual Reproduction in favorable conditions
• Sexual Reproduction is marked by harsh periods

Bryophytes Explained

• Mosses have a waxy coating that helps resist drying
• Rhizoids: thin filaments that anchor plans to the soil; absorb water and nutrients
• Their gametophyte is the main like cycle life stage
• They have specialized reproductive organs that grow from embryos
• It includes liverworts and hornworts with small bodies found in damp soil
• Are non-vascular

Bryophytes Life Cycle

• Gametophytes perform most of the plant's photosynthesis
• Structures Located on the Gametophytes include:
  • Archegonia for egg production.
  • Antheridia producing sperm requires water for mobility to the eggs
• The Zygote develops into a sporophyte with these features:
  • Sporangium is the spore capsule produced through Meiosis.
• Sporophytes grow from a gametophyte body and needs water and nutrients

Tracheophytes Defined

• They are able to grow past 1 meter high due to a tissue transport system
• Tracheophytes are vascular plants, also known as Ferns
• Tracheid: this is water conducting cells with the traits:
  • Hollow tube shape
  • Lignin
  • Thick cell walls
  • Pits, make the cell wall thinner to allow the passing of water

What's A Vascular Tissue?

• Xylem transports water upward from roots; it contains tracheids
• Phloem transports nutrients across the plant using specialized cells

Vascular Plants

• Seedless plants include; club mosses, horsetails and ferns
• Rhizomes are underground stems
• Fronds are large leafy structures
• Sori are clusters of sporangia, often found on the underside of a frond
• They live in the sporophyte stage

Seeds Plants

• Provide an embryo and food supply encased in a protective layer
• They don't require water for gametes to undergo fertilization
• Have adaptations used to colonize land with reproductive processes in flowers and cones
• Pollination transfers sperm
• Embryos are shielded by seeds
• Gametophytes grow inside the reproductive cones and flowers

How Gymnosperm Compares to Angiosperm

• Gymnosperms: produce seeds on the scales of cones and appear first in the fossil record
  • These include pine, spruce, and fir trees
• Angiosperms: are flowering plants including fruits
  • Include most of the crops grown for food

Life Cycle

• Pollen Grains: includes male gametophyte of the seed
• Sperm does not swim in this process
• They spread to the reproductive structure via wind, and pollination
• After fertilization, zygotes grow sporophyte seeds with a protective coating
• Male Cones = Pollen Cones
• Female Cones = Seed Cones, their bases carry ovules where meiosis takes place and produce cells that mature as female gametophytes

Another Life Cycle

• Pollen grain created by seed cones and spreads from the wind
• Catches the ovules, splitting when caught
• Sperm disintegrates as it reaches the female gametophyte, fertilizing the egg
• Then a zygote it made and grows to develop in a protective seed

Angiosperm Traits

• Most Recent / Plentiful in Plant Kingdom
• Sexual Repro Organs known as Flowers
• Seeds Protected by Ovaries
• Fruits develop in a process using the ovaries to disperse seed from parent plant
  • Fruits come from the ovaries
• Seed Leaves Numbers based on Category
• Monocots have one
• Dicots have two
• Can be differentiated by stem structure, seasons they live, or type of petals per flower

Stems, Seasons Petals

• Angiosperms include both woody plants and herbaceous plants

  • Woody plants are made of cells with thick cell walls (ex. Tree Shrubs and vines) . - Herbaceous plants DO NOT produce true wood, like wildflowers

• Lifespan is determined by genes and environment

  • Annual = 1 year or season
  • Biennial - 2 seasons, like 2 years
  • Perennials like wildflowers regrow

• Attract animal pollinators via color/shape

• These flowering plants live in male/female reproductive ways

Anatomy Of A Flower

• Sepals are outside
  • They enclose and protects the developing flower
• Petals are on the inside, and attract pollinators though color and shape
• Petals eventually shed

The Anatomy Deep Dive

• Stamen features male parts
  • Anthers at the tip
  • Pollen is produced at the anther
• Carpels have female parts that produce
  • The ovary creates Gametophytes
  • Styles narrow the carpel to have stigma that attracts pollen

Gametophytes

• Male gametopytes are inside anthers
• Female are known as an embryo sac, and develop in carpels
• The ovule with eggs is enclosed by a protective ovary known as a fruit

Process of Pollination

• Transfers pollen to the female parts
• Some Angiosperms use wind
• Others are pollinated by animals with adaptations such as bright colors

Symbiosis

• Interaction between 2 species
• Mutalism is the benefitting of two species

Double Fertilization

• When a pollen grain lands on the stigma the pollen tube matures
• Generative cells, after dividing, create 2 sperm cells
• This leads to a development toward the ovary in which the ovule is reached and penetrated
• One sperm and an egg is a zygote
• Another sperm is with the embryo sac to form a tissue known as the endosperm

Vegetative Reproduction

• Angiosperms reproduce asexually, making a new individual
• Creates MITOSIS for gametes
• It occurs quicker since there aren't Seeds
• Well-Adapted and Rapid Growing
• Grafting: cuttings used to make identical copies of a plant

Fruit & Seed Development

• Post fertilization, the vascular system provides nutrients to the developing embryo
• Ovary Thickens after seed develop
• Commercially, seeds can be created without seed artificially
• Develop seeds has various approaches used to help animal eat them
• Coatings helps to protect against digestic system
• Sprout in Areas with Competition

What Is Seed Germination

• Plant embryos remain at a state of dormancy for growth
• Germination is a process when a seed sprouts and ends that dormant state
• Germination has those growing plant's first "leaves" called Cotyledons

System of Plant Tissue

• The tissues in the plant include roots and leaves

Dermal & Vascular Tissue

• Dermal: is outer layer that helps to protect the tissues
• Controls gas exchange
• Epidermis- is top layer of tissue
• Cuticle is the waxy layer which helps to prevent loss of water while absorbing the water and passing it

In regards to Vascular tissue

• Consists of xylem and phloem
• (xylem) are tracheids with thinner walls
• (Phloem) is transporting tissue with key organells to help suppor nutrients to plant

What is Ground Tissue

• This produces and stores carbohydrates and helps with the photosynthesis
• Parenchyma creates cells/ a with thin cell walls
• Collenchyma supports flexible cell walls
• Sclerenchyma help stiffen cell walls There are unspecialized regions known as Meristems in which mitosis (cell divison) produces new cells ready to be differentiated/located These are located either on APEX " Tip" or Lateral with aid facilitate growth in the maturation plants

About Roots

• There jobs include
• Anchoring Plants from to soil
• Absorbing minerals and transporting them
• Can be achieved Via TAP root system, with smaller roots that grow down

About the Fibrous Root System

• A root system which consist of a dense network to prevent soil erosion
• Root cap is continuiesly replaced while pushing through the soil

Facts About Roots

• Draws nutrients and H20 soon as in the soil
• pushes raw material with leaves and developing cells
• TAP roots, develop with gives rise to smaller roots while branch
• It is the primary root that extends for large distances

Fibous system consists of the bas stems called stem

• Commonly Found along Grass

Root Cell Division

- Closest the tip/actively divides
      Those zones help elongation with cellular length formation
      Zone of Matuaration/begins and specailized in the cell

Roots

• Hair-like exstensions
• Provides increase of area for water absorption
• Includes STELE TISSUE/ arranged in a root
• A layer known as ENDODERMIS also helps with roots the separate the tissue/help with portion

Roots- Pericycle

Is help outer Layer which allows to

• lateral root

Part Of The Shooting System.

• Vary
• Soft or Woody
• Support - Storage
• Attachment( point nodes)
• Internodes- regions between nodes
• Patiele : stems the leaf with base

Stems Structure

• Parenchyma- store starch and photosynthesis

• Pith- Ground tissue toward interior

• Cortex-Layeer of tissue between vascular and epidermis of stemming

• Bark - outer protection (waterproof))

• Growth- Increase roots

• Elongation- Shoot in division of Meristem

How About Leaves

Rain forest VS Desert

• Large area-vs-transperation
• Waxy substance to-help reduce the water from surface
• Contains Trichomes- Helps-by restricting movement
• Green due too absorption Sites -photosynthesis and environment size thickness
  • A.k.a - LEAVES

About Leaf Structure-

• -Lamia -Widest site -attactting - plants stemming
• Sessil- no-petiole attaching green base - small Midrib- to vein Margin

Patterns of Stemming

• run on lengths without converging
• veins is Net Like
• Vein is Dichot Is arranging based on the stem Has Leaf based that plat with node
• leaves - Arise With stem and +3 Leave - CONNECTED

Leaf Forms

• Simple: blade is completely undivided without reaching
• Compound : divide or branch
• Palm and feathers

There are environmental components such as:

Light for stemming Gravity- orientions Temp/close stoam Predation- disruptive Pests

Environment

• Photogenesis:
• light to space and optimize Photoperiodism- use that time Phototro- - To Grow to compete

Gravitropism = Negative

Hormones

• Cell elognate
• Differentation Of tissues Promote arrangemnt of development leaf
• (inhibiates the leafs following), Citokineses - Promotion
• Germinating (fruit and flower

Absicic- Counter.

More Environmental Responses

Herbivories with defensive from predator increase to protect

Defends by bacteria fungi Seed - Germing Movement constant Response touch Stressing

• In order words, toxins Repel taste and noises. Parasite will cause them.. Activate to abse

Lastly, In Response

Uses plant as source Agents or disease attack

Explore photosynthesis, the process plants use to convert light, carbon dioxide, and water into carbohydrates. Other topics include plant adaptations for sunlight and gas exchange, water, minerals and transport structures. Learn about early photosynthetic prokaryotes.