Acellular or plasmoidal slime moulds ”Biological Classification” Botany Notes Chapter 2, for Class 12-CBSE

Acellular or plasmoidal slime moulds

General characters :

  1. Slimy masses found on decaying leaves and lumber.
  2. Somatic body is free living, multinucleate, naked, diploid mass called plasmodium. Movement occurs by means of pseudopodia.
  3. During unfavourable conditions, entire plasmodium forms many fructifications / fruting bodies (polycentric). The fruting body is called sporocarp which contains a stalk having a sporangium at its tip. The wall of sporangium is called peridium.
  4. Sporangium has an intricate network of cytoplasmic threads called capilitium.
  5. Diploid protoplast forms haploid spores by meiosis
  6. Spore wall is double, outer wall is spiny and sculptured.
  7. On germination, spores produce biflagellate swarm cells or non- motile myxamoebae which act as gametes.
  8. Sexual reproduction is isogamous.
  9. Diploid zygote directly forms the plasmodium which becomes multinucleate by repeated mitotic divisions of the diploid nucleus.
  10. Chief mode of nutrition is saprotrophic.
  11. Vegetative reproduction is by fission.

e.g., physarum. Physarella, Fuligo, Dictydium , Lycogala,   

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