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Parasexuality in Fungi

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Several members of Deuteromycetes, a few Ascomycetes & Basidiomycetes perform plasmogamy,karyogamy & meiosis (haplodisation) in their life cycle but not at a specific time and specified points . This abnormal behaviour of such fungi is termed as parasexuality . Pontecarvo & Roper , 1952 first discovered parasexuality  in Aspergillus nidulans and also coined this term (Greek , para=beside of sex ).A few fungi which perform parasexuality are : Aspergillus nidulans, A.niger, A fumigatus ,A. oryzae, Penicillium chrysogenum , P.expansum, P.italicum,Fusarium oxysporum,Ustilago maydis,etc. Mechanism: Pontecarvo,1956 observed the following steps of parasexuality in Aspergillus  nidulans: (i) Formation of heterokaryotic   mycelium :  Anastomosis of somatic hyphae of different genetic constitution , fusion of some nuclei and their subsequent division and mutation of one or more nuclei of a homokaryotic mycelia in some Ascomycetes resulted into heterokar...
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Degeneration of Sex in Fungi

Degeneration  of sex in fungi :-         In Fungi, simplification of sex organs is observed from lower groups to upper groups:-       1.In Mastigomycotina,a lower group of fungi,isogamy,anisogamy or oogamy resulted into zygote.         2.In Ascomycotina & Basidiomycotina, the sexual reproduction process is progressively simplified in different directions with well- established sexuality.         3 Whereas ,sex organs are absent in few higher fungi of basidiomycotina,though sexual reproduction is well established. Degenaration sex in non - septate and ceonocytic fungi :-           1. The members of Oomycetes of Mastigomycotina , like Pythium , Phytophthora etc.female oogonium is fused by male antheridium to develop either oospore or zygote. It is considered as an advanced type of sexual reproduction.         2. In the members of Zygomycotina like Muco...
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Taxonomy of Angiosperms # Part II# Families of Dicotyledons # Primitive characters of Magnoliaceae

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        Primitive characters of Magnoliaceae                 Hutchinson ,1959has treated Magnoliaceae as the most primitive family among the Angiosperm in his famous book"Families of Flowering Plants"due to the following characters :                                           (1) Spiral arrangement of stamens and apocarpous pistils on the elongated and conical axis.                                                        (2) Presence of tracheids with bordered. pits in the wood of the genus Drimys is  Gymnosperm character.                                    (3) T...
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Plant Physiology for 5th Semester Botany Major NEP 2020

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     Welcome to Plant Physiology, the core of 5th-semester Botany! If lower- level botany focused on classifying green life and learning it's anatomy, this semester shifts the focus inside the cell.Plant Physiology moves beyond what plants look like to examine how they actually work.  It breaks down the chemical mechanisms, energetic balances, and cellular systems that transform sunlight,soil,and air into living tissue. How to Use This Blog Each post breaks down complex biochemical cycles into bite- sized summaries, clear metabolic diagrams, key lab protocol overviews , and exam-focused conceptual questions. Bookmark this page, keep your lab notebook ready, and let's decide the functional science of plants together! Syllabus of BT- 501C  Unit III : Plant Physiology I Chapter 1 : Plant Water Relationship  •Water Potential & it's components •Pathways of water Movement          •Symplast      ...
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