Rhodophyceae (Red Algae) – Class 11 | Chapter – 3 | Short Notes Series PDF

Rhodophyceae (Red Algae): Red Algae belongs to the division Rhodophyta, which is one of the oldest groups of the eukaryotic algae found on earth. The name Rhodophyta is taken from the Greek language where ‘rhodon’ in ancient Greek resembles a rose, and ‘phyton’ resembles ‘plant’. Therefore, we can see that Rhodophyta is the name given to Red Algae species because of their reddish color. The Rhodophyta also comprises over 7000 currently recognized species (with all the ongoing revisions in taxonomy), and it is one of the largest phyla of Algae

The members of rhodophyceae are commonly called red algae because of the predominance of the red pigment, r-phycoerythrin in their body

Characteristics of Rhodophyceae (Red Algae)

Red algae are different from other groups except for diatoms. Listed below are general characteristics of Red Algae.

  • Lack of flagella and centrioles
  • Presence of photosynthetic pigments
  • Found both in marine and freshwater
  • They show biphasic or triphasic life cycle patterns.
  • They are a multicellular, filament, blade structure.
  • Stored food is in the form of starch and polymers of galactan sulphate
  • A pit connection (hole in the septum) is formed between two algal cells.
  • Have a diffuse growth pattern- Apical growth, Complex oogamy (triphasic)
  • These group of red algae is generally found in tropical marine locations
  • The mode of nutrition may either be saprophytic, parasitic or also epiphytic.
  • Their cell walls consist of cellulose and many different types of carbohydrates.
  • Grow on solid surfaces independently or sometimes found attached to other algae.
  • Presence of pit in the cell walls, through which cytoplasmic connec­tions are maintained.
  • The male sex organs are known as spermatangium and the female sex organs are called carpogonia or procarp.
  • Mode of Reproduction: It takes place by all the three means: vegetative, asexual and sexual. Asexual mode of reproduction is by monospores and during the sexual mode of reproduction, they undergo alternation of generations.

Cell Structure of Rhodophyceae (Red Algae)

During the entire life cycle of red algae, they do not have centrioles and flagella present in them. Following are some of the main characteristics of the red algae based on their cell structure:

  • Presence of pit connection between cells filamentous genera
  • Presence of normal spindle fibres
  • Presence of phycobilin pigment granules
  • Presence of un-stacked photosynthetic membranes
  • Absence of chloroplast endoplasmic reticulum and,
  • Presence of microtubules

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By Team Learning Mantras