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Phanerogams > Division I-Gymnosperms

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Estimated time: 13 minutes
Maharashtra State Board: Class 9

Gymnosperms:

Aspect Details
Nature of Plants Mostly evergreen, perennial, and woody plants with unbranched stems and a crown of leaves.
Reproductive Structures Male and female reproductive structures are borne on separate sporophylls of the same plant. Reproductive structures are unisexual.
Seed Features Seeds are exposed and lack a natural covering; hence, no fruits are formed (gymnos = naked, sperms = seeds).
Examples
  • Cycas: palm-like appearance with large compound leaves.
  • Picea: (Christmas tree) Pyramid-shaped conifer.
  • Thuja: ornamental plant with scale-like leaves.
  • Pinus: large, cone-bearing trees in colder regions.
Preferred Environment Found in temperate and cold climates, including forests and mountainous regions.
Pollination and Fertilization Wind-based pollination: seeds form after fertilisation, but fruits do not develop.
Role in Ecosystems Contribute to oxygen production, provide habitats, and prevent soil erosion.
Economic Value Source of timber, resin, and medicinal compounds.
Historical Significance Ancient plant group that evolved before angiosperms, showcasing early adaptations in plant evolution.
 
 
Gymnosperms
Maharashtra State Board: Class 9

Activity

Comparing Garden Plants:

1. Observe plants like Cycas, Christmas tree (Picea), hibiscus, and lily in a garden.

2. Note their similarities, such as being green and autotrophic, and differences in structure and reproduction.

3. Identify differences between gymnosperms (e.g., Cycas, Christmas tree) and angiosperms (e.g., Hibiscus, lily):

  • Gymnosperms have exposed seeds and no fruits, while angiosperms produce seeds that are enclosed in fruits.
  • Gymnosperms are mostly woody and evergreen, whereas angiosperms can be woody, herbaceous, or deciduous.
  • Gymnosperms have separate male and female reproductive structures, while angiosperms often have flowers with both male and female parts.
CBSE: Class 12

Key Points: Phanerogams > Division I-Gymnosperms

  • Naked seeds - Gymnosperms have ovules not enclosed by the ovary wall; seeds remain exposed before and after fertilisation.
  • Vegetative features - Stem branched (Pinus) or unbranched (Cycas); leaves are needle-like with thick cuticle and sunken stomata to reduce water loss; roots are tap roots.
  • Special roots - Pinus has mycorrhiza (fungal association); Cycas has coralloid roots with N₂-fixing cyanobacteria.
  • Reproduction - Reproductive structures are strobili (cones); plants are heterosporous - male strobilus has microsporophylls (produce pollen); female strobilus has megasporophylls (bear ovules); pollination is by air (wind).
  • Fertilisation - Pollen tube carries male gametes to archegonium → fuses with egg → zygote → embryo; ovule develops into seed; life cycle is diplontic (sporophyte dominant).
  • 4 groups - Cycads (Cycas), Conifers (Pinus, Cedrus), Ginkgoales (Ginkgo biloba), Gnetales (Ephedra, Gnetum).
  • Economic importance - Ephedrine (from Ephedra) for respiration; Taxol (from Taxus) for cancer; sago from Cycas; timber, resins, turpentine and paper pulp from conifers.

Video Tutorials

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Related QuestionsVIEW ALL [10]

The giant Redwood tree (Sequoia sempervirens) is a/an ______.

In which plant will you look for mycorrhiza and corolloid roots? Also explain what these terms mean.

Plants of this group are diploid and well adapted to extreme conditions. They grow bearing sporophylls in compact structures called cones. The group in reference is ______.

Endosperm in gymnosperm is formed ______.

Describe the important characteristics of gymnosperms.

Lichen is usually cited as an example of ‘symbiosis’ in plants where an algal and a fungal species live together for their mutual benefit. Which of the following will happen if algal and fungal partners are separated from each other?

  1. Both will survive and grow normally and independent from each other.
  2. Both will die
  3. Algal component will survive while the fungal component will die.
  4. Fungal component will survive while algal partner will die.

Based on your answer how do you justify this association as symbiosis.

Each plant or group of plants has some phylogenetic significance in relation to evolution: Cycas, one of the few living members of gymnosperms is called as the ‘relic of past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?

Write a note on the economic importance of gymnosperms.

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