Exercise 6: Gymnosperms

• Seed-producing plants can be further differentiated by the presence or absence of an ovary (the fruit) which serves as the protective layer enveloping seeds
• Gymnosperms


  Plants with unenclosed seeds, derived from a Greek word: gymnos, 'naked' and sperma, 'seed', which can be literally translated as "naked seeds"
• Major groups of Gymnosperms

  • Cycadophyta
  • Ginkgophyta
  • Coniferophyta/Pinophyta
  • Gnetophyta
• PART I. THE SEARCH FOR REAL GYMNOSPERMS

  1. Check out for gymnosperms in the campus or hometown area

  2. Take close-up photos (habit, leaves, cones) of all plants that you suspect as gymnosperms

  3. Collect parts of the shoot and reproductive structures, if allowed

  4. Take photos of the collected structures highlighting details

  5. Use photos and herbarium specimens to check if you have representative that are native or endemic to the Philippines or Southeast Asia

  6. Compile your report as a group MS Powerpoint presentation and submit via LMS
• PART II: LIFE CYCLE OF SELECTED GYMNOSPERMS

  Make hand-drawings and label the life cycle of Gnetum, Cycas, Pinus, and Ginkgo
• Conifers are distinct from other gymnosperm groups because of the presence of cones
• Cones are dry fruits (since the seeds are not enveloped in a fleshy tissue) and are formed by overlapping of scales which bear the seeds
• Conifer leaves protect buds and conserve water.
• Conifer Shoot System

  • Acicular leaves – long needle-like leaves
  • Fascicle- bundle of leaves and may be 1 leaf (monofoliar) or 2 to 5 (multifoliar)
  • Terminal bud -serves as the primary growing point of plants found at the tips of stems, and
  • Lateral buds -growing point found near the leaves and may become vegetative shoots such as stems or leaves or reproductive structures such as flowers
• Conifer leaves have a distinct tissue arrangement which allows them to grow long and thin.
• Conifer Leaf Tissues

  • Cuticle
  • Resin Canal
  • Epidermis
  • Endodermis
  • Xylem
  • Phloem
  • Hypodermis
  • Mesophyll
  • Stoma
• Vascular bundle (or stele) is a part of the transport system of plants and is composed of the pericycle, xylem, and phloem.
• Vascular Tissues in Conifer Stem and Roots:

  • Xylem- transports water from roots to shoots
  • Phloem- transports photosynthates from shoots down to roots
  • Pericycle - a thin layer of parenchyma or sclerenchyma cells at the outermost part of a stele
• Conifer Reproductive Parts: The Pine Cone

  • Rachis, Scale, Bract Scale, Prickle, Umbo, Apophysis, Peduncle
  • Ovulate (female) cone: Ovule, Ovuliferous scale, Sterile bract, Megaspore, Ovary, Cone axis
  • Staminate (male) cone: Cone axis, Microporphyllis, Microspore/pollen sac, Pollen
• Conifers Upclose:

  • Conifer Shoot System
  • Conifer Leaf Tissues
  • Vascular Tissues in Conifer Stem and Roots
  • Conifer Reproductive Parts of Pine Cone: ovulate (female) and staminate (male)