Life History of Homobasidiomycetes

Question 1

hymenium

Answer 1

sexually fertile layers of the basidiocarp & other non-fertile cells that are located on the surface of basidiocarps

Hymenium includes: paraphyses, cystidia & hyphidia
Act as spacers b/w basidia & maintain moisture

Question 2

what fungi in homobasidiomycetes lack hymenium? Where do their basidia reside?

Answer 2

gastromycetes

basidia reside in the gleba

Question 3

basidia arise from what type of hyphae?

Answer 3

dikaryotic hyphae

Question 4

what are the diff kinds of basidia in the homobasidiomycetes?

Answer 4

incipient basidium

probasidia

metabasidia

Question 5

incipient basidia

Answer 5

presence of numerous vacuoles prior to & just when nuclei fuse during karyogamy

Question 6

probasidia

Answer 6

site of karyogamy, binucleate

Question 7

metabasidia

Answer 7

site of meiosis

Question 8

describe the inital development of basidia & sterigma?

Answer 8

Clear area on the cap & at the base has an enlarging vacuole with meiosis & initiation of sterigma

Sterigma is further developed by swelling at the basal vacuole & development of initial spores

Question 9

what occurs in basidia after meiosis?

Answer 9

mitosis occurs yielding 4 haploid nuclei

they disintegrate into 4 spore protoplasts

Question 10

how are homobasidiomycetes basidia characterized?

Answer 10

having 4 mature basidia with 4 spores sitting asymmetrically on sterigma

Question 11

how do spores reach the basidia?

Answer 11

spore protoplasts are pushed out of the basidium through the sterigma & apophysis occurs

Question 12

apophysis

Answer 12

tips of sterigma inflate creating an area for the spore protoplasts

Question 13

summary of spore development

Answer 13

spore protoplasts are pushed out of the basidium through the sterigma & apophysis occurs

Development of convex abaxial & concave face of spores:
Spore wall thickens
Asymmetrical growth on the abaxial face occurs
Elongation

Mature spores attached to the sterigma at the hilum (part of spore) & hilar appendix (apiculus)

Before the spores separate from the sterigma a hilar plug & sterigmal plug are formed

Question 14

what needs to occur before a spore separates from the sterigma?

Answer 14

a hilar plug & sterigmal plug form

Question 15

Describe the process of spore release

Answer 15

water build up in the droplet causes a change in the center of mass causing the sterigma to be pulled downwards

the water build up is shifted as the droplet fuses with the spore covering causing the tension (tensile force) in the sterigma to be released catapulting the spore away

Question 16

ballistospores

Answer 16

catapulted spores by forcible discharge

Question 17

what do spores germinate into?

Answer 17

homokaryotic hyphae which then develop into primary mycelium as a pore in the spore wall forms

Question 18

what process causes the primary mycelium to develop into secondary mycelium

Answer 18

dikaryotization by somatogamous plasmogamy

Question 19

simultaneous division in the dikaryon is facilitated by

Answer 19

clamp connections

Question 20

what do clamp connections do?

Answer 20

maintenance of dikaryotic cells

preserves pairing of compatible nuclei

Question 21

resting spores germinate by:

Answer 21

forming basidia & basidiospore –> rusts & smuts (Teliomycota)

repetitive production of ballistospores –> jelly fungi (Tremella)

Conidia

Question 22

how are Basidiomycota hyphae characterized?

Answer 22

dolipore septum

Question 23

what do hyphal divisions contain?

Answer 23

septal pore with a dolipore running through it

Question 24

dolipore

Answer 24

barrel-like structure parallel to the hyphal longitudinal axis

Question 25

parenthosomes

Answer 25

dense endoplasmic cap-like structure, overarch the pore on either side of the dolipore perforated or imperforated

Question 26

the septal pore in basidiomycota without parenthosomes are plugged by what instead?

Answer 26

pull wheel like dense body

Question 27

how is plasmogamy accomplished?

Answer 27

fusion of hyphal cells deposition of protoplasts into a common cell

Question 28

oidia

Answer 28

preformed spore-like structures 'cut' from hyphae

Question 29

how do nuclei transfer to a common cell when dikaryotizing?

Answer 29

migrate to the cell in association with microtubules

Question 30

when dikaryotic cells divide, the nuclei align such that

Answer 30

The lead nucleus divides obliquely into a clamp connection The compatible nucleus trails behind so the daughter nuclei are aligned with the longitudinal axis of hyphae

Question 31

describe how clamp connections maintain the dikaryotic state?

Answer 31

Clamp connection will carry one of the lead nuclei daughter cells into the new subtending hyphal cell facilitating it to join with one of the daughters derived from the trailing nucleus

Question 32

dolipore is _____ to the hyphal ____ axis

Answer 32

parallel longitudinal