Plant Structure and Function

• In order to develop a clear understanding of the material the following steps are recommended:
  • Read class notes and text book chapters prior to the lecture
  • Take and review personal notes
  • Ask questions about material that is unclear
  • Consult other texts to broaden understanding
  • Manage time well in advance of tests to ensure adequate preparation
• Learning considerations are based on:
  • Correctly identifying and naming structures by spelling
  • Linking the form and function of structures together
  • Ability to show knowledge of the evolutionary adaptations of plant structures
• Learning outcomes include:
  • Ability to see the difference between dicotyledonous and monocotyledonous flowers
  • Introducing different types of inflorescences and flowers
  • Examining the structure of flowers and reproductive parts
  • Introduction to the terminology of flowers
  • Studying the different types of fruits and seeds that result from fertilisation
• Organisms are grouped into three domains:
  • Bacteria with cyanobacteria
  • Archaea
  • Eukarya
• Bacteria are prokaryotes
  • Cell wall are made of peptidoglycan or lipopolysaccharide
• Archaea are bacteria-like
  • Cell wall of pseudopeptidoglycan
• Eukarya includes organisms that have organelles, including a nucleus

General Concepts

• Reproduction creates either offspring with identical genes or new individuals that are genetically different from parents
• In stable environments asexual reproduction can selectively produce well-adapted progeny
• In less stable environments sexual reproduction can produce progeny that are more fit in changing environments

Reproduction benefits and shortcomings

• Sexual reproduction creates progeny that are genetically diverse from two parents
  • Some are more adapted than parents but others are not
  • Offspring cannot colonize a new site as rapidly because offspring are not adapated for it.
  • Changes in habitat may adversely affect offspring
  • Isolated individuals cannot reproduce
• Asexual reproduction has progeny that are genetically identical to each other
  • All offspring are as adapted as parents unless a genetic mutation occurs
  • Rapid colonisation of new site is possible
  • Offspring harmed by changes in the habitat.
  • Isolated individuals are vulnerable to decimation

Flower Structure and Pollination

• Cross-pollination happens with pollen from a different individual
• Self-pollination happens with pollen from the same flower or another flower on the same plant
• Plant mechanisms to promote cross-pollination include:
  • Decrease probability of self-pollination by different maturation times
  • Increases chances by attracting pollinators
  • Anthers and Stigmas mature at different times
  • Plants have compatibility barriers with chemical reactions
  • Plants with many flowers that open at different times can prevent self pollination

Flower characteristics

• Androecium includes the stamen
  • Stamen includes the anther and filament
• Gynoecium includes the pistil
  • Pistil includes the stigma, style, and ovary
• Perianth is a non-reproductive component of a flower
  • Perianth includes the petals(corolla) and the sepals(calyx)
• Flowers that lack either stamen or carpels(essential organs) are imperfect flowers
  • Perfect Flowers has both stamen and carpels
• Dioecy: species that produce only staminate flowers and carpellate flowers
• Monoecy: species that produce both staminate and carpellate flowers
  • Dioecy ensures cross-pollination
• Long styles, stamens and buried ovaries protects the ovary and ovules from pollinators
• Bases of the stamen, petals and sepals fuse, creating a thick protective layer around the ovary
• An inferior ovary is epigynous
• A superior ovary is hypogynous
• Intermediate/partially buried ovaries are half-inferior
  • Ovary position describes the region where the fruit and ovules will develop

Inflorescences

• Defined as the arrangement/organisation of flowers on a stem
• Two basic arrangements of inflorescences
  • Determinate: apex is converted to a flower, the flower tends to open before the lower flowers
  • Indeterminate: lowest or outermost flowers open first, and new flowers are initiated at the apex
• Types of inflorescences: spike, raceme, panicle(=compound raceme), head(capitulum), umbel, compound umbel

Seeds and Fruits

• Drupe simple fleshy fruit single seed enclosed in a stoney endocarp
  • Example: peaches and almonds
• Berries develop from a compound ovary with more than one seed
  • Pericarp entirely fleshy and skin is very thin
    • Example: tomato
• Hesperidium: berry with a leathery skin with oils and the Family Rutaceae
  • Example: lemons, oranges and grapefruits
• Legumes: split along two sides
• The parts of a seed include the:
  • Endosperm(stores reserve food)
  • Seed Coat(protects the seed)
    • Testa
    • Tegmen
  • Plumule
  • Epicotyl
  • Hypocotyl
  • Radicle
  • Cotyledon