Structure and reproduction in agaricus

Structure and reproduction in agaricus is described with proper detail..The context is taken from the book Diversity of Plants by Tanveer Ahmed Malik

1. Structure and Reproduction in Agaricus Presented by: Ali Abbas Aslam Contact me on WhatsApp for ppt file 0309-8400094

2. Taxonomic Position Kingdom : Fungi Division : Basidiomycota Class : Agarico mycetes Order : Agaricales Family : Agaricaceae Genus : Agaricus Specie : A.campestris / A.californicus

3. Structure Plant Body consists of two major parts: Vegetative mycelium Basidiocarp Mycelium Basidiocarp

4. Vegetative Mycelium It may be: Primary Mycelium Monokaryotic, short lived, develops from germination of basidiospore. Hyphae are septate and hyaline. Cells are short, contain oil globules, vacuoles and thin protoplasm. Secondary Mycelium Dikaryotic, arise by dikaryotization through somatogamy of two monokaryotic hyphae. Long, branched, septate and have short cells. Dolipore septa are present between adjacent cells. More abundant and produce mushrooms year after year

5. Vegetative Mycelium Tertiary Mycelium Mycelium producing basidiocarps is sometimes referred to as tertiary mycelium. It forms complex tissue which produces basidia.

6. Reproduction Fungus reproduces sexually usually Definite sex organs are absent Plasmogamy is done by fusion of two compatible hyphae, which results in the formation of a dikaryon The nuclei of dikaryon undergo conjugate divisions with that of the dikaryon to produce dikaryotic secondary mycelium The basidiocarp develop from the hyphae of subterranean, perennial secondary mycelium

7. Basidiocarp / Sporophore The aerial part of the fungus is known as fruiting body or basidiocarp. It is also called mushroom. It produces by tertiary mycelium

8. Structure of Basidiocarp Pileus Upper part, circular and expanded, at young condition enclosed by velum Stipe F leshy pinkish-white stalk, as pileus grow in size velum ruptures and the remnants surround the stipe called annulus Lamellae or Gills A cavity is present under the pileus in which large number of thin, vertical, platelike structures are present called lamellae or gills Gills are first pinkish but as spore matures they become dark brown Pileus enclosed in velum

9. Development of Basidiocarp It starts as a tiny swelling consisting of a knot of subterranean hyphae of the secondary dikaryotic mycelium This swelling enlarges into a broadly ovoid structure the “basidiocarp primordium” Then a ring shaped cavity is formed “prelamellar chamber” The portion of the primordium above the prelamellar cavity finally develops into the pileus and the below portion into the stipe Development of Basidiocarp

10. Internal Structure of Basidiocarp Basidiocarp is composed of interwoven hyphae which run parallel to each other in stipe They are compactly arranged to form pseudoparenchymatous tissue in the pileus region In stipe the central hyphae is loosely arranged with prominent air spaces forming the medulla The outer hyphae forms cortex The pileus also shows similar arrangement of hyphae into the central medulla and outer cortex Some of the hyphae present in pileus develop into the lamellae or gills Pseudoparenchymatous tissues

11. Structure of lamellae Each lamella consists of three parts: Hymenium Sub hymenium Trama Hymenium Fertile region, club shaped, binucleate forming palisade like layer on both sides of lamella, they developed to form b asidia Some are sterile and are called paraphysis Rest of them are elongated cells. They protrude beyond the paraphysis and are called cystidia Lamella

12. Trama Internal to hymenium is trama Multinucleated, elongated cells, extend from hyphae of the pileus The hyphae run more or less longitudinally Sub hymenium In between the hymenium and trama there is region composed of hyphae arranged at right angle to those of trama The cells are isodiametric and binucleate

13. Karyogamy Formation of sterigmata Formation of basidiospore Hilum Separation from Basidium Context from Book of Tanveer Ahmed Malik Development of Basidium and Basidiospores

14. The mycelium of A garicus has a tendency to grow in all directions from a central point to form a large invisible circular colony When the mycelium becomes mature at tips, sporophores are produced. These sporophores appear in a circle. These circles of mushrooms are commonly called “fairy rings ” A.campestris produces dark green rings in grass Damages the lawns, produce a thick fungal mat that prevents water from reaching the grass roots below. Also deplete soil nutrients Fairy Rings

15. Diagrammatic life cycle Graphical life cycle