5 Questions
What are the main food reserves of Phaeophyta?
laminarin and mannitol
Which photosynthetic pigments are found in Phaeophyta?
Fucoxanthin
Kelps are the only algae with true conductive tissues like xylem and phloem.
False
Phaeophyta show alternation of generation with both haploid and diploid stages. The haploid stage is represented by the ____, and the diploid stage may be isomorphic or heteromorphic.
thallus
Match the following components of brown algae with their descriptions:
Holdfast = Attaches the algae to the ground/substrate Stipe = Stem-like structure Laminae (Blade) = Leaf-like structure
Study Notes
Characteristics of Phaeophyta (Brown Algae)
- Cell walls composed of cellulose fibers bound with alginic acid
- Food reserves consist of laminarin (a soluble polysaccharide) and mannitol
- Reproduction occurs through both sexual and asexual means, with higher phaeophyta having a life cycle consisting of haploid and diploid stages and alternation of generation
Photosynthetic Pigments
- Chlorophyll a and c
- Beta carotene
- Violaxanthin
- Fucoxanthin
Kelps (Laminarales)
- Can reach up to 70 meters in length
- Have internal tissue differentiation, but lack true conductive tissues like xylem and phloem
- Adapted to a wide range of marine environments, including tidal, intertidal, and deep zones
Adaptations
- Some members have adaptive bladders that help them float, enabling photosynthetic parts to be near the water surface where there is sufficient light
- Form brown patches on exposed surfaces like glass, rock, or gravel in aquarium environments, causing nuisance
Morphology
- Three types of structures: holdfast (attaches to the ground/substrate), stipe (stem-like structure), and lamina (blade, leaf-like structure)
Classification
- Classified into three classes based on life cycles of species: Isogenrate, Heterogenerate, and Cyclosporea
- Examples of classes:
- Isogenrate: Dictyota
- Heterogenerate: Laminaria
- Cyclosporea: Fucus
General Characteristics
- Typical seaweed construction: a holdfast, stipe, and lamina
- Growth occurs through division of apical cells
- Oogamous reproduction, with fusion between small male gamete and large female gamete
- Tissue differentiation observed in the internal structure of the blade
- Examples of species:
- Fucus: flattened thallus and dichotomous branching pattern
- F. vesiculosus: pairs of air bladders along its thallus, providing buoyancy
Explore the main characteristics of Phaeophyta, also known as brown algae, including cell construction, food reserves, and reproduction methods. Learn about the life cycle and stages of this type of algae.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
