define hyphae

filamentous thread-like structures that make up mycelium

define mycelium

root-like structure of fungus consisting of a mass of branching thread like hyphae

define septa

cross walls that divide hypha into separate cells

chytrids key characteristics (5)

- single celled - lacks true mycelium - cell wall may be cellulose instead of chitin - contains a thallus with branching rhizoids - includes parasitic and saprophytic species

asexual reproduction of zygorhizidium planktonicum

uninucleate haploid thallus grows on surface of Asterionella formosa. encystment occurs inside inside producing zoosporangia. uniflagellate zoospores are released resulting in haploid thallus or gametangia.

sexual reproduction of zygorhizidium planktonicum

heterothallic gametangia provide evidence of sexual reproduction. fuse by conjugation tube and the male protoplast migrates into female gametangium. fertilization occurs occurs to form a thick walled resting spore. nuclei fuse forming diploid zygote. after a period of dormancy, meiosis occurs. new meiosporangium germinates and haploid zoospores are released.

what is unique about Phylum Deuteromycota

they only reproduce asexually

compare & contrast 3 conidia structural features found in class Hyphomycota

1. terminal thalloconidium - separated from conidiophore by septum, may not produce new conidium, if one in produced it forms in diff place 2. phialoconidium - conidium on special cells (phialide), aseptate until fully grown, new conidium produced when mature 3. tetraradiate conidium - dont germinate while suspended in water, germ tubes produced within few hours, morphological adaptation to moving water

how does hyphomycota play a key role in organic matter cycle of rivers

play key role in breaking down leaf litter further. increases food value of leaves.

biphasic

two phases - dominant haploid (n) phase & zygote diploid (2n) phase

define coenocytic

multi-nucelate aseptate mycelia