Plant Kingdom
[PREMIUM NCERT MODULE • BOTANY DIVERSITY]
Simple, thalloid, autotrophic, and largely aquatic organisms.
| Class | Common Name | Pigments | Stored Food |
|---|---|---|---|
| Chlorophyceae | Green Algae | Chl a, b | Starch |
| Phaeophyceae | Brown Algae | Chl a, c, Fucoxanthin | Mannitol/Laminarin |
| Rhodophyceae | Red Algae | Chl a, d, r-Phycoerythrin | Floridean Starch |
- Requires water for sexual reproduction (transfer of antherozoids).
- Plant body is Gametophyte (n). Attached by rhizoids.
- Liverworts: Thalloid body (e.g., Marchantia). Gemma cups for asexual reproduction.
- Mosses: Leafy stage (e.g., Funaria, Sphagnum). First stage is Protonema.
- First terrestrial plants with Xylem & Phloem.
- Main plant body is Sporophyte (2n).
- Heterospory: Producing two types of spores (Micro/Mega). E.g., Selaginella, Salvinia. (Precursor to seed habit).
- Ovules are not enclosed by any ovary wall.
- Seeds are naked (no fruits).
- Examples: Cycas (unbranched stem), Pinus (branched), Sequoia (giant redwood).
- Mycorrhiza found in Pinus; Coralloid roots in Cycas (associated with N2-fixing cyanobacteria).
- Haplontic: Sporophyte is only zygote. (e.g., Volvox, Spirogyra).
- Diplontic: Gametophyte is single/few-celled. (e.g., Fucus, Gymnosperms, Angiosperms).
- Haplo-diplontic: Both stages multicellular. (e.g., Bryophytes, Pteridophytes, Ectocarpus, Polysiphonia).
Plant Kingdom HOTS Questions
[ SYSTEMATICS & EVOLUTION LOGIC ]
1. They lack vascular tissues (Xylem/Phloem) for efficient water transport.
2. They lack true roots.
3. Most crucially, external water is essential for the motile antherozoids (male
gametes) to swim towards the archegonium for fertilization. Hence, they are "Amphibians" of the plant
kingdom.
Selaginella is Heterosporous (produces micro and megaspores). The megaspore is retained within the megasporangium on the parent sporophyte for some time, and the female gametophyte develops inside it. This retention and nourishment is a crucial evolutionary step toward the development of the seed habit seen in higher plants.
In Gymnosperms, the endosperm is Haploid (n) and develops before fertilization (it is essentially the female gametophyte). In Angiosperms, the endosperm is typically Triploid (3n) and develops after double fertilization as a product of triple fusion.
Volvox forms spherical colonies consisting of thousands of individual biflagellate cells. These cells work in coordination but are still individuals. These colonies are often called Coenobium. It shows a haplontic life cycle.
Mycorrhiza (in Pinus) is a symbiotic association with fungi to help in water and mineral absorption. Coralloid roots (in Cycas) are specialized roots associated with Nitrogen-fixing Cyanobacteria (Anabaena/Nostoc). Both are adaptations for nutrient uptake in diverse environments.
Similar to amylopectin and glycogen.
Asexual reproduction in liverworts (like Marchantia).
Juvenile leafy stage in mosses; develops from spores.
Sphagnum; used as fuel and packing material due to water holding capacity.
Diplontic (exception among Algae).
Chlorella and Spirulina (Single-cell proteins).
Sporophyte (2n).
Gametophyte (n).
Protein besides starch (found in Chlorophyceae).
Wolffia.
Eucalyptus (over 100m).
Exclusive to Angiosperms (Syngamy + Triple Fusion).
Leaf-like structure bearing naked ovules.
Algin from Brown algae; Carrageen from Red algae (Hydrocolloids).
(Advanced logic - based on subsidiary cells arrangement).
Plant Kingdom: 50 Mastery Facts
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