Botany 359 First Lecture Examination, Fall 1999 Name_________________________

I. Definitions:

a) _______________________The asexual stage in the life cycle of a pleomorphic fungus

b) _______________________Sterile hyphae arising in a perithecium from above the level of the developing asci and growing downward among the asci with the tips remaining free.

c) _______________________An ascus with thick, often separable inner and outer walls

d) _______________________The production of a small outgrowth from a parent cell; a method of asexual reproduction

e) _______________________The totality of structures enclosed by the ascocarp wall, including the asci

f) _______________________Pertaining to a cell that contains a pair of closely associated, sexually compatible nuclei

g) _______________________A system of two closely appressed unit membranes that are involved in ascospore delimitation; also know as the ascus vesicle

h) _______________________Cytoplasm within an ascus that is excluded from the ascospore when the ascospore is delimited

i) _______________________A genetic system that restricts the fusion of mycelia of the same species that have different controlling genes

j) _______________________A condition in which genetically different nuclei are associated in the same protoplast or same mycelium

k) _______________________An elongated boat-shaped ascocarp opening by a longitudinal slit

l) _______________________An alternate form of a genetic locus that lacks significant sequence homology with its alleles

m) _______________________The fusion of two nuclei

n) _______________________A stalked spore-producing structure, the apex of which develops into a round a powdery mass at maturity

o) _______________________A multicellular spore that contains melanin and has the numerous septa all arranged in the same axis.

p) _______________________Term used to describe an ascus with a thin wall; the wall collapses and disappears with maturity.

q) _______________________Membrane-bound, often odd-shaped structures that are associated with and often plug the septal pore in ascomycete hyphae.

r) _______________________A compact somatic structure on which or in which fructifications are formed.

s) _______________________The receptive hyphae of the ascogonium that fuses with the male cell

t) _______________________An electron-dense, spherical body found in the hyphae of Ascomycota and usually concentrated near septa

II. Using only the spaces provided, complete the chart with the appropriate words.

Feature	Operculate ascus	Inoperculate ascus
ascus tip
symmetry of spore
size of spore
number of rows of spores
amyloid reaction
ascocarp

III. Provide an explanation in a diagram of the ploidy number and origin of the paraphyses, hymenium, antheridium and ascogonium, ascogenous hyphae, and ascocarp wall of a fungus in the Pyrenomycetes. Label All Parts including the centrum. Confine your answer to the space provided.

IV. Ophiostoma ulmi, the causative agent of the Dutch Elm Disease, is not considered an obligate parasite. Furthermore it is considered a polymorphic fungus with anamorphic stages as well as teleomorphic stages and thus the holomorph of this fungus is complex.. Answer the following questions concerning the life cylce of this fungus. Confine your answers to the spaces provided.

A. What is cerato-ulmin and how does it allow Ophiostoma ulmi to kill Dutch Elm trees?

B. Diagram the teleomorphic stage and indicate where it is found in the life cycle of this fungus.

C. Define anamorph, teleomorph, and holomorph.

D. What are the anamorphic stages of Ophiostoma ulmi, where are they found, and what are their function?

F. Ophoiostoma ulmi is a complex holomorph. What advantages does having such a life cycle confer on this fungus?

V. Compare Vegetative Incompatibility with Sexual Incompatibility in the Ascomycetes. Include in your answer a discussion MAT loci and HET loci and the difference between homogenic incompatibility and heterogenic incompatibility. Confine your answer to the space provided.

Extra Point Question. You must make an effort to answer all questions on the test before you will receive credit for the following extra point question.

Diagram the following structures and label all parts. Use only the space provided.

An multiloculate ascostromata with the appropriate sterile cells and with the appropriate ascus. The ascospores in the ascus are biseriate and phaeophragmospores.

A stroma with several perithecia. In one perithecium show periphyses and apical paraphyses. In a second show paraphyses. In a third show a unitunicate, inoperculate ascus with uniseriate, hyalodidymospores.