21 public questions tagged with this topic.
Fungi may reproduce vegetatively by fragmentation, fission and budding. Spore formation is classified separately as asexual or sexual reproduction depending on the type of spore produced.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Five Kingdom Classification and Kingdom Plantae Animalia
In Phycomycetes, sexual reproduction results in the formation of a zygospore by the fusion of two gametes. The gametes may be similar in morphology or may differ from each other.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Deuteromycetes and Economic Importance
In Basidiomycetes, karyogamy and meiosis occur in the basidium, usually producing four basidiospores. These spores are formed exogenously on the basidium, and the basidia are arranged in basidiocarps.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Deuteromycetes and Economic Importance
Fungal sexual reproduction involves plasmogamy, or fusion of protoplasms; karyogamy, or fusion of nuclei; and meiosis in the zygote, which produces haploid spores.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Deuteromycetes and Economic Importance
Sex organs are absent in Basidiomycetes. Plasmogamy occurs through the fusion of two vegetative or somatic cells belonging to different strains or genotypes, producing a dikaryotic structure.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Deuteromycetes and Economic Importance
In Ascomycetes, asexual spores called conidia are produced exogenously on special mycelium called conidiophores. Their sexual spores, the ascospores, are produced endogenously inside sac-like asci.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Phycomycetes Ascomycetes Basidiomycetes
In Ascomycetes and Basidiomycetes, plasmogamy may be followed by an intervening dikaryotic stage before karyogamy. Each cell then contains two haploid nuclei, represented as n + n, and the phase is called the dikaryophase.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Bacteria - Structure and Economic Importance
Cleistothecium describes completely closed, spherical to subspherical ascoma lacking any ostiole or natural opening, characteristic of powdery mildews like Podosphaera, Erysiphe and Eurotiales including Aspergillus and Penicillium sexual stages. Peridium membranous composed of interwoven hyphae encloses irregularly scattered globose prototunicate asci each containing ascospores; release occurs only after peridial decay, mechanical cracking or ingestion by arthropods. This closed architecture provides protection in xeric, epiphytic or cleistocarpous niches against desiccation, differing from open cup apothecium, flask perithecium with pore and mushroom-like basidiocarp of basidiomycetes.
Ref: Webster & Weber Introduction to Fungi Chapter 6 Ascomycota; Campbell Biology 12th ed. Chapter 31 Fruiting Bodies
Ascomycota produce sexual meiospores termed ascospores typically eight per ascus following meiosis plus one mitotic division inside sac. Ascospores form endogenously within sac-like ascus often arranged linearly or irregularly, wall contains melanin and hydrophobins resisting desiccation and UV. Upon maturation asci rupture or forcibly shoot spores via turgor pressure mechanism. Basidiospores exogenous on basidia externally, zygospores thick-walled diploid resting spores in mucorales, conidia asexual mitospores. Ascospore morphology - shape, septation, ornamentation - aids generic identification. Presence inside asci defines Ascomycota encompassing morels, truffles, yeasts, dermatophytes, many plant pathogens like powdery mildews.
Ref: Campbell Biology 12th ed., Chapter 31: Ascomycota Ascospores Inside Asci; NCERT Class 11 Ascomycetes Ascospores; NCBI Ascomycete Reproduction
Basidium constitutes characteristic meiosporangium of Basidiomycota, club-shaped dikaryotic cell within hymenium of gills, pores or other sporulating surfaces of mushrooms. After karyogamy, meiosis produces four haploid nuclei migrating onto sterigmata forming basidiospores externally above basidial surface. Ascus sac-like housing ascospores inside, sporangiophore supports sporangium in zygomycetes, conidiophore bears conidia asexual. Club shape maximizes spore exposure for forcible discharge using surface tension catapult mechanism called Buller's drop. Basidium morphology varies: holobasidia non-septate, phragmobasidia septate in rusts, but clavate shape conserved. Mitosome identification utilized immunofluorescence targeting iron sulfur cluster assembly proteins confirming mitochondrial evolutionary origin despite minimal proteome.
Ref: Campbell Biology 12th ed., Chapter 31: Basidium Club-Shaped Meiosporangium; NCERT Class 11 Basidiomycota Basidium; NCBI Basidium Structure
Compatible mating types in heterothallic Zygomycota sense each other via trisporic acid pheromones inducing progametangial hyphal tips to meet and swell. Contact triggers septation to form progametangia, walls dissolve at contact point, plasmogamy merges cytoplasm containing haploid nuclei. Nuclei pair then karyogamy produces diploid zygote enlarging into thick-walled zygospore surrounded by zygosporangium exhibiting warty ornamentation. Conidia and sporangiospores asexual mitospores, ascospores belong to ascomycetes. This conjugation process names conjugation fungi, essential for genetic recombination and dormancy surviving unfavorable conditions before meiospore formation inside germ sporangium after meiosis.
Ref: Campbell Biology 12th ed., Chapter 31: Zygomycota Conjugation Zygospore Formation; NCERT Class 11 Phycomycetes Fusion; NCBI Mating Mucorales
Basidiospores formation follows meiotic division within basidium after diploid nucleus formed via karyogamy. Meiosis I and II yield four haploid nuclei that migrate into sterigmata developing into basidiospores exogenously. Some species follow additional mitotic division to produce eight spores increasing output. Mitosis, binary fission and budding produce genetically identical clones without reduction, not characteristic here. Meiosis ensures genetic recombination, segregation of mating-type loci and reduction from transient diploid zygote to haploid dispersal propagules essential for Basidiomycota life cycle maintaining haploid-dominant dikaryotic mycelial phase after spore germination and dispersal.
Ref: Campbell Biology 12th ed., Chapter 31: Meiosis in Basidium Basidiospores; NCERT Class 11 Basidiospore Formation - Meiosis; NCBI Basidiosporogenesis
