(click here for help navigating the site and for misc site info)

 

Index | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16  

BIO 341 Lecture Topic 11: Hyphal aggregates

For best results in printing, download the PDF version of this page 

Corresponding Readings:
  • TBA 
Printed Notes, Main Points:

(click on the main point headings to jump to the selected location in the notes)


Fungal Hyphal Aggregate

        

         Terminology for Basic Tissue-like Organization of Fungi

 

Plectenchyma -   hyphal aggregations that appear tissue-like, but are not because formed from hyphae not cells (2 types)

 

Prosenchyma -   Plectenchyma having hyphae that remain apparent at structure's maturity

 

Pseudoparenchyma -   Plectenchyma having hyphal origin obscurred at maturity of structure.

 

 

 

Hyphal coordination yielding multi hyphal aggregates is manifested by:

 

a)      interhyphal contact causing formation of plectenchyma

 

b)      coordinated differentiation with neighboring hyphae

 

c)      ultimate formation of morphologically distinctive, nearly macroscopic to truly macroscopic structures.

313

(Back to main points)


Vegetative Hyphal Aggregates

 

I.       Strands -

                     linear hyphal aggregates with the capacity to extend unidirectionally

 

         A.         Mycelial Strands -

                                 retain hyphal organization at maturity

 

         B.         Rhizomorphs -

                     aggregate formed by coordinated apical extension of a # of aggregated hyphal tips

 

 

         vs reproductive

318

(Back to main points)


Characteristics of Strands

 

a)      Thickness is variable (e.g. a few hyphae to several mm)

 

b)      Can arise either from a colony or a sclerotium

 

c)      Potentially capable of unlimited linear extension

 

d)      Give rise to new colonies or to a reproductive structure

 

f)       Most often associated with the production of reproductive bodies (e.g. basidiocarps)

319

(Back to main points)


II.      Sclerotia*

 

         Firm hyphal aggregates of vegetative hyphal origin, which exhibit determinent growth.

 

         "hard time structures"

 

1.      * Characteristics = have many sizes and shapes

 

2.      Often rounded or lobed

 

3.      Can be as lg as 10 cm in diameter

 

4.      Usually darkly pigmented

 

5.      Often exhibit pseudoparochmastous construction and much anastomosis

 

6.      "Cells" contain large concentrations of stored endogenous substrates

322

(Back to main points)


Asexual Reproductive Hyphal Aggregates*

        

 

sing

pl

I

Synnema

Synnemata

II

Pycnidium

Pycnidia

III

Acervulus

Acervuli

IV

Sporodochium

Sporodochia

*aggregates that are associated with conidium production

325

(Back to main points)


How formed:

 I       Mycelial strands

 

   

         Main hypha is "adopted" by so-called "following hyphae" that have branches that can grow backwards or forward.

 

II.       Rhizomorphs

 

 

 

         Coordinated apical extension of a # of hyphal tips

320/165b

'(Back to main points)


1.      Synnema - simple structures that result when conidiophores aggregate

         a.         Often appear more complex than they really are

         b.         Often macroscopic and mistaken for slime mold fruit bodies

         c.         Often conidiophores exhibit extensive anastomosis

         d.         Such fungi usually members of Fungi Imperfecti* or anamorphs of Ascomycota

?*      Hyphomycetes - form class

 *       Coelomycetes - form class

326

(Back to main points)


Conidioma of Coelomycetes

2.      Pycnidium - a flask-shaped, globose or    oval-shaped structure that looks like a cleistothecium or a perithecium but has a cavity filled with conidiophores and conidia instead of asci- and ascospores.

         Often identified incorrectly as an ascocarp.

3.      Acervulus* - functionally a structure similar to a pycnidium, but structurally different by being formed by        plant pathogenic fungi in association with plant tissue.

*        Oten appears to be a pustule formed just under plant epidermis, which erupts and exudes conidia

329

(Back to main points)


Conidioma (continued)

4.      Sporodochium -  large mass of short conidiophores and hyphae which arise together from the surface of a structure          (multihyphal aggregate) called a stromata (stroma).*

*        Structures like those in which locuoles are sometimes formed by Loculomycetes.

*        Stromata can give rise to:

         1.         conidia

         2.         locuoles & asci

         3.         sclerotia

332

(Back to main points)


Sexual Reproductive Hyphal Aggregates*

*Carpophores** of Euascomycotina

 

name

class association

1.

cleistothecia

Plectomycetes

2.

perithecia

Pyrenomycetes,  Laboulbeniomycetes

3.

apothecia

Discomycetes

4.

ascostroma

Loculomycetes

                                                                            

**       Ascocarp-type carpophores***

         *Ascomas

***         a)      formed from pseudoparenchymatous tissue derived from the ascogonium

         b)         from primary protective tissue derived totally from parent hyphae

         c)         secondary protective tissue formed only after stimulation of ascogonium

                     335

(Back to main points)


Sexual Hyphal Reproductive Aggregates* (continued)

Basidiocarps

formed by:

         1.         Localized & coordinated branching and swelling of aggregated hyphae (usually dikaryotic)

         2.         Secondarily by hyphal compaction, wall thickening, gelatinization and coloration

         3.         Basidiocarp development seems to be triggered by environmental conditions, since dikaryotic colonies may grow indefinitely without producing a basidiocarp

345

(Back to main points)


Basidiocarp Developmental Patterns among 
some Hymenomycetes (Homobasidiomycotina)

1.      Gymnocarpus*

                     primordium develops into a gilled mushroom-like structure in such a way that basidia are always exposed during formation**

                                                                             

*        as in Aphyllophorales

**       as per S. commune

346

(Back to main points)


Basidiomycete developmental patterns leading to mushrooms (continued)

Agaricales

Hemiangiocarpic

         gills and basidia of mushroom develop in "hidden" fashion, although mushroom development is apparent

Angiocarpic

         mushroom development is not obvious until mushroom is relatively mature; gills again hidden.

347

(Back to main points)


Review of Holobasidiomycotina

Classes and Orders

Subphylum - Holobasidiomycotina

Class - Phragmobasidiomycetes* (5 orders)

Order - Tremellales
(have cruciately septate Basidia)

Order - Auriculariales
(have transversely septate Basidia)

* have septate basidia

Class – Holobasidiomycetes (27 orders)**

Order - Dacrymycetales
(have tuning-fork type basidium)

Order - Tulasnellales (have holobasidia with swollen sterigmata)

** All but these two have typical holobasidia


Basidiomycota Classification (cont.)

Subphylum - Holobasidiomycotina * (cont.)

Class – Holobasidiomycetes (selected orders cont.)

Order - Agaricales (the mushrooms)

Order – Boletales (the fleshy pore fungi)

Order – Cantharelles (chantarelles, and tooth fungi, etc.)

Order - Exobasidials

Order - Gautieriales

Order - Hymenogastrales

Order - Lycoperdales (the puffballs, earth stars, etc.)

Order - Melanogastrales  

Order - Nidulariales (the bird's nest fungi)

Order - Phallales (the stinkhorns)

Order - Porales (woody shelf fungi or woody bracket fungi)

Order – Thelephorales (the coral and leather fungi)

Order – Sclerodermatales (the earth balls)

* most have typical holobasidum, but different kinds of basidiocarps                       355

(Back to main points)

(Back to top of page)

 

Home | Syllabus | Lectures | Exams | Links | Help

For questions, comments, or suggestions,
please send e-mail to:
pluong@mail.utexas.edu

The University of Texas at Austin

Hit Counter