SXConline
Bio Diversity
Rhizopus

Objectives:

  1. To know about the vegetative structures.
  2. To know about the reproductive structures and mode of reproduction

 

Requirements:

Apparatus        : Dissection Box

Material           : Rhizopus

 

Observations:

Visual: Rhizopus is a saprophytic fungus and grows on bread. The plant is achlorophyllous with several branched hyphae having pin head. It appears white cottony mass in young and dark brown in matured.

 

Microscopic: Rhizopus is highly branched and contains coerocytic hyphae. The body contains branched absorptive hyphae called rhizoidal hyphae, group of aerial hyphae called sporangiophore bearing sporangia at the tip and curved horizontal hyphae called stolen arising from the same node. The mycelium contains several nuclei but no septum.

The hypha contains central vacuole, glycogen and cell wall formed by fungal cellulose.

 

Reproductive Structures:

Asexual reproduction takes place in favourable condition by means of spores produced in sporangium. Each sporangium has two regions-a fertile peripheral region and a sterile central region, columella. Large numbers of spores surround the columella which is capable of forming new mycelium.

Sexual reproduction takes place by conjugation forming a conjugation tube. The zygote is formed by the fusion of two nuclei of opposite strain which gets surrounded by a thick wary wall and forms zygospore.

 

Classification and Identification:

Kingdom         : Plantae (Presence of cell wall and large central vacuole)

Sub-kingdom  : Cryptogamae (Non-flowering plants)

Division           : Thallophyta (Thallus body, no tissue differentiation, absence of vascular tissue, no    embryo formation, unicellular reproductive structure)

Sub-division    : Fungi (Achlorophyllous, heterotrophic, cell wall made up of fungal cellulose)

Class                : Phycomycetes (Body is asepted and multinucleated i.e. coerocytic, large no. of spores are formed in sporangia, spores are non-motile)

Genus              : Rhizopus (large no. of sporangiophore arise from the same point, rhizoidal and aerial hyphae are opposite, presence of stolen, formation of zygospore)

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