Untitled Quiz

Introduction to Botany

• Biology is the scientific study of life.
• Botany is the scientific study of plants (and many organisms formerly considered plants).
• In simpler terms, botany is the biology of plants.

What is a Plant?

• Plants contain chlorophyll.
• Plants transform light energy to chemical energy.
• Plants do not move or cannot move.
• Plants respond to environmental changes like seasons or weather.
• Plants are at the bottom of the food chain and are therefore responsible for the powers of regeneration.

Function of Plants

• Plants provide food.
• Plants provide clothing.
• Plants provide buildings and furniture.
• Plants provide bio-diesel (from oil palm and Jatropha).
• Plants contribute to the environment.

Subdisciplines of Botany

• Systematics/taxonomy
• Morphology
• Anatomy
• Cytology
• Physiology
• Genetics
• Ecology

Systematics

• Systematics is the scientific study of biological diversity.
• An ordered system is needed to track the millions of organisms on Earth.
• A name helps identify and communicate information about an organism.

Taxonomic Hierarchy

• The taxonomic hierarchy groups species into an ordered, hierarchical classification system.
• Kingdom > Division (Phylum) > Class > Order > Family > Genus > Species

Development of Classification

• Traditionally, organisms were classified as either plants or animals.
• Non-motile autotrophs were placed in the plant kingdom.
• Motile heterotrophs were placed in the animal kingdom.
• Later discoveries showed that this system was incomplete.

Development of Classification Issues

• Euglena is a unicellular, motile autotroph.
• Fungi (mushrooms and molds), traditionally categorized as plants, are non-motile heterotrophs.

Types of Organisms

• Prokaryotes (bacteria) lack nuclei, organelles, 9+2 flagella, chromosomes, multicellularity, and sexual reproduction.
• Eukaryotes (almost all other organisms) have nuclei, organelles, 9+2 flagella, DNA associated with histone proteins forming chromatin/chromosomes, sexual reproduction, and are mostly multicellular.

Five-Kingdom System

• Robert Whittaker proposed a five-kingdom system.
• All Prokaryotes were placed into a single kingdom (Monera).
• Eukaryotes were categorized into four kingdoms: Plantae, Fungi, Animalia, and Protista.

Kingdoms

• Animalia: Motile, multicellular, lack plastids and cell walls, heterotrophic, and reproduce sexually.
• Plantae: Non-motile, multicellular, have plastids, autotrophic, cell walls made of cellulose, adapted to life on land, and mostly reproduce sexually.
• Fungi: Non-motile, filamentous, lack plastids, cell walls made of chitin, heterotrophic (from dead or living matter), mostly multicellular (except yeast), reproduce sexually and asexually.
• Protista: Lack multicellularity, a diverse group of unicellular, colonial, and multicellular eukaryotes that lack the defining characteristics of plants, animals, and fungi. (Examples: protozoa, algae, molds)

Plant Kingdom Divisions

• Bryophyta: Tiny plants lacking vascular systems, transportation occurs through capillary action. (Examples - mosses, lumut)
• Pteridophyta: Larger plants, require vascular systems for transportation. (Examples - ferns, paku-pakis)
• Spermatophyta: Seed plants; subdivided into Gymnosperms and Angiosperms.
  • Gymnosperms: Four divisions: Coniferophyta, Ginkgophyta, Cycadophyta, and Gnetophyta; do not produce flowers, seed plants.
    • Coniferophyta: Pine (Pinus) example
      • Male pine cone structure
      • Female pine cone structure
  • Angiosperms: Flowering plants; further subdivided into classes.
    • Magnoliopsida (dicot): 250 families (e.g., Leguminosae, Asteraceae, Moraceae, Malvaceae, Euphorbiaceae, Solanaceae)
    • Liliopsida (monocot): 50 families (e.g., Gramineae, Orchidaceae, Palmae, Musaceae)

Root Morphology

• Tap root: Dicotyledon roots, the primary root enlarges, forming the main root system.
• Fibrous root: Monocot roots, the primary root doesn't last long; adventitious roots replace the primary roots, creating the fibrous root system.
• Adventitious roots: Roots that develop in addition to primary roots.
• Functions of Roots: Anchor plants, absorb water and minerals, produce plant hormones (auxin, gibberellin), store food.
  • Stored Carbohydrates in Roots: Carbohydrates are converted into starch for storage.
• Origin of Roots: Radicle is the first root to emerge from a seed.
• Root Hairs: Tiny projections from the root epidermis, increase surface area for water and mineral absorption.
• Root Tip: Made up of apicaI meristem and root cap; actively producing new cells.
• Primary Root vs. Secondary/Lateral Roots: Primary root develops from the radicle, while secondary/lateral roots branch out from the primary root.
• Anatomy of a Dicot Root: Diagram of the major parts of a dicot root, including epidermis, cortex, endodermis, pericycle, phloem, xylem.
• Root Systems:
  • Taproot systems
  • Fibrous root systems
• Modified Roots: Specialized roots for functions outside of absorption or anchorage.
  • Tuberous roots (food and/or water storage, e.g., cassava, carrot)
  • Pneumatophores: Roots from underground roots for respiration (e.g. bakau)
  • Parasitic roots (obtain food from a host, e.g., striga)
  • Aerial roots (e.g., prop roots, aerial buttress roots, air roots such in orchids)

Stem Morphology

• Functions of Stems: Support leaves, transport water and food between roots and leaves, photosynthesis in young stems, store food.
• Modified Stems:
  • Rhizomes (horizontal underground stems with nodes and internodes)
  • Bulbs (underground buds covered by modified leaves for food storage - e.g. onion)
  • Tubers (enlarged underground stems that store food - e.g. potatoes)
  • Runners/stolons (horizontal above or below ground stems; aid in asexual reproduction; e.g. strawberries, grasses )
  • Stem tendrils (support climbing plants)
  • Thorns (defense mechanism)
  • Cladodes/cladophylls (modified stems that function like leaves)
  • Pseudobulbs (swollen stem segments found in orchid plants, used for water storage).
  • Suckers/tillers (shoots that originate from below ground)
• Stem Parts: Diagram of stem structures like nodes, internodes, axillary buds, terminal buds, bud scales, leaf scars, vascular bundles scars, lenticels.

Leaves

• Functions of Leaves: Trap light for photosynthesis, making carbohydrates from CO2 & water, store food, protection, water storage.
• Leaf Parts: Diagram of a leaf, including blade, petiole, midrib, veins, base, and apex.
• Leaf Arrangement: The different ways leaves are arranged on a stem (opposite, alternate, whorled, decussate, distichous)
• Leaf Venation: The arrangement of veins on a leaf (parallel, net).
• Leaf Margin Variation: Different forms, including entire, dentate, dissected, serrate, crenate. .
• Modified Leaves: Modified leaves that perform specialized functions (tendrils for support, spines for defense, bracts for attracting pollinators, pitchers for trapping insects).
• Specialized Leaf Parts:
  • Sheath (base of leaf surrounding/wrapping the stem - grasses)
  • Auricle (small, ear-shaped appendage)
  • Ligule (membrane appendage on the upper leaf sheath - grasses)
  • Stipules (leaf-like appendages at the base of the petiole).
  • Epicalyx (group of leaves resembling sepals below the true calyx).
  • Trichomes (outgrowths on the leaf surface).