Explain The Asexual And Sexual Reproduction Phases In Zygomycetes Group Of Kingdom Fungi?

Asexual reproduction occurs by sporangiospores, chlamydospores and oidia. These all are mitospores. Sporangiospores are developed under favorable conditions. Around 2 to 5 sporangiophores develop from holdfast. The tip of spoarangiophore forms sporangium. It is separated from rest of structures by columella. Sporangiums give rise to number of spore which are non motile are known as sporangiospores. They are dispersed by air. Chlamydospores are formed under un favorable condition. Most of them are thick walled and some of them are thin walled referred as gemmae. When the conditions change they give rise to mycelium. Oidia divide by budding and they play a vital role in fermentation of alcohol. They also produce various organic acids. Rhizopus is of heterothallic type. When the mycelia have different mating types and have the same medium it produces trisporic acid. They stimulate the mycelia and form zygophores. Zygophores of both the strains come in contact and produce progametangia. Its terminal part separates from rest. The terminal part is referred to gametangium and the rest is referred to suspensor. The gamentagium has protoplast which is multi nucleate and the common wall gets dissolved. Two of the protoplast fuse and form diploid zygote and a spore known as zygospore. It can be brown or black in color. The protoplast has many diploid nuclei and it undergoes meiosis. This leads to production of haploid nuclei. Out of all the haploid nuclei, one of them survives rest degenerate one by one. The survived nucleus divides number of times mitotically and forms numerous haploid nuclei. They are of single strain. The protoplast increases in size leading to the breakdown of wall of zygophore. The protoplast which comes out is known as promycelium. It gives rise to sporangium known as germ sporangium. It forms haploid or meiospores known as germ spores which are dispersed by air. These spore later on form mycelium.