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A Nu!Ritional and Cytologioal Study of Rosbllinia Limoniispora

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A Nu!Ritional and Cytologioal Study of Rosbllinia Limoniispora A NU!RITIONAL AND CYTOLOGIOAL STUDY OF ROSBLLINIA LIMONIISPORA. David s. Hayman A theais submitted to the Faoulty of Graduate Studies and Researoh in partial fulfilment of the requirements for the degree of Master of Science. Department of Botany, KoGill University, Montreal. April 1963. ACKNOWLEDGEMENTS I am very grateful to Dr. Charles M. Wilson for providing me with a culture of Rosellinia and for the benefit of his direction during this investigation, to Dr. Howard Whisler for his interest and suggestions on various occasions, to Dr. Roy ~. Cain, Department of Botany, University of Toronto, for the identification of the species studied, to Dr. Robert ~. Craig for instruction in photomicrography, and to all fellow graduate students and members of the Botany Department at McGill who have been a constant source of encouragement during my research programme. Special thanks are due to McGill University for a University Scholarship during the first academie session and a Graduate ~aoulty ~ellowship during the second, and to the National Research Council of Canada for assistance through Dr. Wilson during the summer months. -----------·····-· CONTENTS -PAGE INTRODUCTION The Problem••••••••••••••••••••••••••••••••••••• 1 TaxonoiD.J. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 PART I - NUTRITION INTRODUCTION AND LITERATURE REVIEW.............. 3 MATERIALS AND METHODS••••••••••••••••••••••••••• 9 EXPERIMENTS AND RESULTS••••••••••••••••••••••••• 16 DISCUSSION AND CONCLUSIONS •••••••••••••••••••••• 21 PART II - CYTOLOGY INTRODUCTION AND LITERATURE REVIEW•••••••••••••• 26 MATERIALS AND METHODS••••••••••••••••••••••••••• 34 CYTOLOGICAL OBSERVATIONS •••••••••••••••••••••••• 38 DISCUSSION AND CONCLUSIONS•••••••••••••••••••••• 46 SUMMARY. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 55 BIBLIOGRAPHY •••••••••••••••••••••••••••• • • • • • • ••• • • ••• • • 57 PHOTOGRAPHS ••••••••••••••••••••••••••••••••••••••••••••• 67 ------------------- ....... --~· INTRODUCTION The Problem The number of cultural and cytological etudies in the fungi has witnessed a marked upsurge in the past two decades. The use of modern cytological techniques has made possible detailed etudies of fungus nuclei with important consequences in the fields of cytotaxonomy and cytogenetics in particular. Xuch work bas also been undertaken to elucidate some of the factors affecting fruiting by investigating the nutrition and metaboliaœ of fungi which fruit in pure culture, either for its intrinsic value or with a view to providing the fungus cytologist and morphologist with a means of obtaining a ready supply of material with which to work. Such material contains all stages of growth, which are often lacking in field collections, and certain morphological characteristics may be seen to be due to variations in nutrition and therefore are not always strict criteria for distinguishing species and varieties. The following investigation is concernsd with soms of the factors intlusncing the production of perithecia in purs culture by Rosellinia limoniispora, together with details of crozier formation and the nuclear changes in the developing ascus. Taxonomy The genus Rosellinia Css. & De-lot. is a pyrenomycste and was formerly placed in the family Sphaeriaceae (Saccardo 1892, Lindau 1897, Glumann and Dodge 1928, Bessey 1950). Most authorities now place - 2 - it in the family I7lariaceae (Arnaud 1925, Miller 1928 and 1949, Luttrell 1951, Glumann 1952, Cain- persona! communication). tiller in 1928 considered Rosellinia as having perithecia consieting of a definite wall plus a thin peeudoparenchymatous layer equivalent to the stroma of Hypoxylon, and the dark ascospores suggested a close relationship with the Xylariaceae. In 1949 he emphasised the ascua crown character of Rosellinia as showing further affinity with the Xylariaceae. The aaci of Rosellinia limoniispora Ellis & ETerhart appear to have lost the apical apparatus characteristic of the Xylariaceae, and this species probably representa one of the many linea of evolution leading to groups of Ascomycetes with evanescent asci (Cain - personal communication). The imperfect stage, lacking well defined conidiophores, defies identification. -----------~-·····-~ - 3 - PAR! I - IUTRITION INTRODUCTION AND LITERATURE REVIEW Oulturing fungi creates many problems, and ~though perhaps the saprophytic ascomycetes are more readily cultured than most, there are several factors which require investigation in as many genera, species, and even strains as possible in order that certain generalisations may be subetantiated and new ones evolved. Many pyrenomycetes require certain conditions before they will produce abundant peritheoia for study. One such pyrenomyoete is Rosellinia limoniispora which fails to fruit unless several factors are taken into acoount. Since a multitude of factors are involved in sexual re­ production, and sinoe nutrition is an important factor, the nutri­ tional experimenta that can be performed on any organism are prao­ tically unlimited. One therefore has to analyse those factors which appear to play major roles in the organism selected for study. One may experiment, for example, with temperature, light, and the cul­ tural medium itself where auch factors as pH, growth substances, carbohydrate source, carbon: nitrogen ratio and nitrogen source are perhaps the most important. In addition to testing one or several variables at a time, one may also take a more radical approach and study the medium during growth to see which compound& are utilised by the fungus and in which order and quantity. - 4- In a survey of the Tast literature on fungus nutrition only the most pertinent examples are oited. A. Environmental laotors (1) Light is usually needed before perithecia will be pro­ duced. Tylutki (1958) for example, working with Gelasinospora calospora var. autosteira, f'ound that few or no peritheoia or protoperithecia were produced in the dark. Sometimes not a great deal of light is necessary, as in the case of Ascobolus magnificus where Yu (1954) f'ound that apothecie. were produced in the presence of light at an optimum of' one hour per day. Sometimes different species of' the same genus vary in their response to light. Suoh a genus is Nectria where Hanlin (1961) f'ound that N. gliocladioides and N. peziza would not form perithecia if kspt in continuous dark­ neas, whereas I. ipomoeae normally formed perithecia in cultures kept in constant darkness although not as abundantly as those kept in light. {~~) ~eaperature Aa.s a marked effect on fruiting. There is usually a broad range of temperature within which fruiting can take place, but fruiting bodies are normally produced in large quantities only at temperatures very close to the optimum. This optimum temperature is usually between 20 and 25°0. Gelasinoapora calospora var. autosteira produces ascospores beat at 20°0 (Tylutki 1958), and apecies of Nectria fruit beat at 24°0 (Hanlin 1961); - 5- Neurospora crassa fruits well at 18°0 (Westergaard and Mitchell 1947). Unusually high optimum temperatures tor growth may occur as in the case of Sordaria destruens and Sordaria timicola (Hawker 1951) although this optimum may vary with the carbohydrate source (Hawker 1947a). (lll) pH is important, and its ettects may be modified by altering the concentrations of various growth factors present in the medium. Lilly and Barnett (1947), for example, found that a pH of 3.6 - 3.8 inhibited perithecial production in Sordaria fimicola, but the addition of thiamin overcame this. Although thiamin itself was not an essential growth factor, culture media containing it reverted to an optimum pH !aster than media without it. B. Nutritional Factors (1) Growth substances. It is well known that many fungi are unable to synthesize certain necessary vitamine or are capable only of a limited synthesis. The two vitamine most commonly deficient, either singly or together, are biotin and thiamin. No perithecia are produced in Sordaria fimicola in the absence of biotin and mycelial growth is eparse (Barnett and Lilly 1947a). Hackbarth and Collins (1961) tried various combinations of ten vitamine on three species ot Gelasinospora and found that biotin was the factor li­ miting growth. Ceratostomella timbriata is heterotrophic with respect to thiamin (Barnett and Lilly 1947b). Sordaria (Melanospora) destruens - 6 - needs both biotin and thiamin for perithecial production (Hawker 1939a). The proportions of vitamine are also important. :Barnett and Lilly (1947b) showed that sexual reproduction occurs in Ceratostomella fimbriata only when the ratio of thiamin to the amount of nutrients in the medium is rela~ively high, i.e. the formation of perithecia is inhibi~ed as the amount of thiamin is reduced whilst the nutrient level is kept constant. Their resulta with thiamin correspond to their resulte with biotin on Sordaria fiaicola where the number of perithecia produced is proportional to the concentration of biotin (Barnett and Lilly 1947a). Similarly Hawker (1942) found that the concentration of glucose optimal for fruiting rose with an increasing concentration of thiamin. The major effect of a vitamin may sometimes be on sugar uptake. For example, Bretzloff (1954) showed that where no biotin was added to a medium in which Sordaria fimicola was growing, very little sugar was used. (11) Sugar source. In general mycelial growth increases and perithecial production decreases as the concentration of sugar in. the medium is increased.
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