Tvelve-species of the alqa class Eustigmatophyceae were studied by means of light and electron microscopy, with particular reference to structural aspects of the vegetative cells and the flagellar apparatus of the zoospores. The Vegetative cells are shown to have microfibrils (probably cellulose)' in the cell wall (Vischeria stellata), lamellate vesicles in the cytoplasm of all the species observed and a clear connection between the cfiloroplast endoplasmic reticulum and the nuclear envelope only in representatives of the Monodopsidaceae. Microfibrils (probably cellulose) were also found in the cell wall of the tribophycean species Ophiocytium malus. The most significant results on uni- and biflagellate zoospores include the observation of a Golgi body for the first time in a eustigmatophycean zoospore (Vischeria helvetica) and the first reconstruction of the system of flagellar roots in the Eustigmatophyceae (V. stellata). This consists of a rhizoplast and four microtubular roots: roots R1 (3 MTs) and R2 (2 MTs) originate-at basal body B1 and run anteriorly around the flagellar swelling; root R3 (5 MTs) arises between the basal bodies and runs to the posterior end of the cell; root R4 (2 MTs) originates at basal body B2 and curves around the eyespot. For comparison, zoospores of the tribophycean species Heterococcus marietanii and H. protonematoldes were also studied. A system of flagellar roots consisting of a small rhizoplast and three microtubular roots, two directed anteriorly and one posteriorly was confirmed. A double helix was shown to be typical of the transition region of the flagella in-this genus. The few observations on settling cells shoved the withdrawal of the complete flagellar apparatus including the swelling-and the possibility of reformation of the pyrenold in Vischeria from material stored in the spiral vesicles during the motile stage. In preliminary observations on mitosis and cytokinesis it was found that, at early stages, basal bodies appear near the nuclear surface and the chloroplast and the pyrenoid divide. Cytokinesis seems to occur by a cleavage furrow. My reconstruction of the flagellar root system in Eustigmatophyceae shows sufficient similarities with the flagellar, roots of other heterokont algal and fungal classes to justify its, inclusion with them in a single division,the Heterokontophyta. On the basis of this observation and the main ultrastructural features known for these classes,a phylogeny is, constructed for the whole group and the probable characteristics of the, common ancestor are proposed.

The highly sulphated, methylated polysaccharide isolated from Pachymenia Carnosa, a red seaweed, was shown to contain D- galactose, 2-o (underscore) methyl-D- galactose, 6-o (underscore) -methyl- D- galactose and 4-o (underscore)-methylgalactose. The polysaccharide was desulphated with methanolic hydrogen chloride. Methylation of the desulphated polysaccharide revealed that it was composed entirely of (1→73) and (1→4) links in approximately equal amounts. Treatment of the polysaccharide with alkali showed that the majority of the ester sulphate groups were alkali-stable. Partial hydrolysis and acetolysis studies indicated that the polysaccharide was extremely complex, and contained alternate (1→3) and β (1→4) glycosidic linkages. There is evidence for the presence of D-galactose-6-sulphate.

Aeodes ulvoidea, a red seaweed of the Grateloupiaceae, yielded a highly sulphated polysaccharide which was shown to contain D- and L-galactose, 4-0-methy-L-galactose, 2-0-methyl - D- and L-galactose and 6-0-methyl-D-galactose, together with chromatographic traces of xylose and mannose. The sulphate was not labile to alkali, but it was largely removed with methanolic hydrogen chloride. Periodate oxidation of the polysaccharide, methylation of the de sulphated polysaccharide, and investigation of fifteen oligosaccharides from partial hydrolysis and acetolysis studies of the polysaccharide, indicate that (a) the polysaccharide is composed of a backbone of D-galactose residues which are 1,3- and 1,4-linked (b) at least some regions of alternating structure do occur (c) the 2-0-methylgalactose is linked through the 4-position (d) the 4-0-methyl-L-galactose is present as single unit side chains glycosidically linked to the galactose backbone at position 6, and (e) most of the 6-0-methyl-D-galactose is linked to the 4-position of 2-0-methyl-D-galactose.

A highly sulphated, methylated polysaccharide, aeodan, isolated from the red seaweed Aeodes orbitosa was shown to contain galactose, 2-̲̲O-methyl-D-galactose, 4-O̲-methyl-Lgalactose, 6-O̲-methyl-D-galactose, xylose, and glycerol. The polysaccharide was desulphated with methanolic hydrogen chloride. Periodate oxidation of aeodan and desulphated aeodan, followed by reduction and hydrolysis, revealed the presence of 1,4- and 1,3-linked galactose residues and 1,3-linked 6-O̲-methy l-D-galactose residues in aeodan. Treatment of aeodan with sodium hydroxide revealed that the majority of the ester sulphate groups were alkali stable. Methylation of desulphated aeodan revealed that the polysaccharide was composed entirely of 1,3 and 1,4 links. Methylation of aeodan revealed the presence of 1,3- and 1,4- linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose-2, 6-disulphate units in the polysaccharide. Partial hydrolysis of aeodan resulted in the isolation and characterisation of 3-O̲-D-galactopyranosyl-D-galactose and 4-O̲-ß-D-galactopyranosyl- D-galactose. A sulphated, methylated polysaccharide, phyllymenan, isolated from the red seaweed Phyllymenia cornea was shown to contain galactose, 2-O̲-methyl-D-galactose, 4-O̲-methyl L- galactose , 6-O̲-methyl -D-galactose, and xylose. The polysaccharide was completely desulphated with methanolic hydrogen chloride. Periodate oxidation of phyllymenan before and after desulphation revealed that removal of the sulphate ester groups had not produced any new adjacent hydroxyl groups. Alkali treatment of phyllymenan revealed that the ester sulphate groups were alkali stable. Methylation studies on phyllymenan revealed the presence of 1,3- and 1,4-linked units, 1,3-linked galactose-2-sulphate, and 1,3-linked galactose- 2,6-disulphate units in the polysaccharide. Partial hydrolysis of phyllymenan revealed the presence or 4-O-̲ß- D-Dgalactopyranosyl- D-galactosc, 4-O-̲ß-D-galactopyranosyl -2-0- methyl-D-galactose, a galactosylgalactose composed of D and L-galactose, and adjacent 6-O̲-methyl- and 2-O̲-methyl-D- galactose units in the polysaccharide.

Hot-water extraction of Anatheca dentata, a red seaweed belonging to the family Solieriaceae, yielded a mixture of polysaccharides. Fractionation of this mixture with Cetavlon gave a glucomannan as minor component and a highly sulphated major component, which gave D- and L-galactose, D-xylose and small amounts of 3-0 (underscore)-methylgalactose, pyruvic acid and uronic acid on hydrolysis. All subsequent investigations were carried out on the sulphated major component. The sulphate was not labile to alkali, but was removed with methanolic hydrogen chloride. Periodate oxidation of the polysaccharide before and after desulphation indicated that new a-glycol groups were formed during desulphation. All the xylose units in the polymer were cleaved by periodate and this, together with the fact that the major xylose product from methylation analysis of the desulphated polymer was the 2,3, 4-tri-0 (underscore)-methyl derivative, indicated that the xylose occurs as a non-reducing end-group. Methylation of the desulphated polysaccharide revealed the presence of 1,4- and 1,3- linked D- galactose and 1,4- linked L-galactose units in the polymer. D-Glucuronic acid occurred as non-reducing end-groups. Summary, p. 1.

Algal collections from eight lakes in southwestern British Columbia have been examined. The desmid flora consists of 205 species and 44 varieties in 26 genera. Two genera, Spino-closterium and Spinocosmarium, and several species of other genera, are reported for the first time from British Columbia. Seasonal changes in the abundance and kinds of desmids occurring in collections are noted. Cultural studies on the variability of Triploceras gracile and T. verticillaturn were undertaken to determine the validity of subspecific characters used in the genus. These studies showed that the apical radiation of the semicell (the number of lobes at the end of the semicell) can vary from biradiate (2-lobed) to quadriradiate (4-lobed) within a single clone. Thus in the genus this character must be discarded as a taxonomic criterion. The morphology of the protuberances of the semicells was constant in both species, and is a useful subspecific character. A number of abnormal forms occurred in cultures but were not observed in field collections. The nuclear cytology of Triploceras was investigated. T. verticillaturn has the largest chromosomes yet reported for the Desmidiaceae, almost 20 u in length measured at late prophase in colchicine treated cells. The chromosome number for this species is n = 15-20. The chromosomes of T. gracile are smaller, but no chromosome counts were obtained for this species. / Science, Faculty of / Botany, Department of / Graduate

Field and culture studies have been carried out with the epiphytic red alga, Ceramium codicola J. Agardh, with the objective of determining what factors in its biology cause it to be limited to growth on one host plant, Codium fragile (Suringar) Hariot. A survey of epiphytes of C. fragile and C. setcheIIii confirm the absence of C. codicoIa on C. setcheIIii and shows that C. codicola is the most abundant epiphyte on C. fragiIe. More species of epiphytes were present in wave sheltered areas. C. codicoIa was not present in samples from the Strait of Georgia. In culture, C. codicoIa grew to reproductive maturity apart from C. fragiIe from spores, but the life history was not completed. The presence of living or extracted C. fragiIe or C. setcheIIii did not promote germination, growth or reproduction of C. codicola, and typically inhibited it. C. codicoIa did not grow well at temperatures above 15°C in culture; C. fragiIe, Ceramium pacificum and C. gardner i grew weII at 10-18°C. Rhizoids of C. codicola have bulbous tips, which appears to be genetically determined. Substratum can affect later development of these rhizoids, which may obscure the bulbous nature of the rhizoid tips. C. codicoIa is unable to produce digitate holdfasts on its rhizoid tips, as was observed in other Ceramium spp. , and may only be able to attach by entangling its rhizoids in loosely constructed substrata such as Codium spp. C. setcheIIii is not suitable because it is too compact, and penetration of rhizoids is inhibited. Field studies show that C. codicoIa is reproductive throughout the year, although reduced in the winter. Thallus length was also reduced in the winter. In addition, thalIi were longer in wave sheltered sites, and longer in the upper regions of their intertidal distribution. Male and female gametophytes and tetrasporophytes of C. codicola exhibit a hetermorphism in branching pattern. Gametophytes differ from tetrasporophytes by having more primary branches and larger angles of branching. Females differ from males by having a higher degree of proliferous branching, resulting in a higher number of primary branches and a higher branching ratio. Branching pattern in females may be the result of continued growth of involucral ramuli, and it may optimize reproductive potential. / Science, Faculty of / Botany, Department of / Graduate

Several aspects of L-threonine dehydratase from seven species of unicellular marine planktonic algae were investigated; (1) the disulfide group requirement for activity of the enzymes from two cryptomonads, (2) monovalent inorganic cation requirement for enzyme activity, (3) substrate specificity and substrate analog inhibitions, (4) allosteric activation and inhibition and diverse effects from other amino acids, (5) pH optima of the algal enzymes with particular emphasis on the elucidation of the unique pH-activity response of the enzyme from Hemiselmis virescens. The threonine dehydratases from Chroomonas salina and Hemiselmis virescens require disulfide groups for enzyme activity as exemplified by the specific inhibition exerted by all thiol reagents tested, which inhibition could be partially reversed or prevented by the appropriate treatments. Sulfhydryl group requirement: for enzyme activity was confirmed and it was demonstrated that these groups are essential for feedback inhibition from L-isoleucine. All algal enzymes appear to require monovalent alkali-metal cations for full expression of activity, more specifically K⁺₄ and NH⁺₄. Anacystis marina was exceptional in showing maximal stimulation from Li⁺. Organic cations were without effect whereas some inhibition from certain divalent cations (Zn²⁺ , Cu²⁺) and anions (N0⁻₃, I⁻ , C10⁻₃) were observed, whilst HP0²₄⁻ and SO²₄⁻ were stimulatory. Aside from L-threonine, the algal enzymes extended substrate activity to L-serine and L-aliothreonine. In addition to its known threonine dehydratase, Chroomonas salina appeared to produce a serine dehydratase which accounted for the relatively high substrate activity observed toward L-serine with this species. Inhibition from substrate analogs was limited to L-homoserine and L-serine, despite the substrate activity of the latter. The mechanism for the peculiar mode of inhibition evinced by L-homoserine remains unknown whereas that of L-serine appears to result from inactivation of the enzyme. With the exception of Cyclotella nana and to a lesser extent Hemiselmis virescens, all the algal enzymes were subject to feedback inhibition from L-isoleucine, which inhibition was pH dependent, subject to reversal by L-valine, and could be duplicated by the analog L-O-methyl threonine. Several other amino acids (L-leucine, L-norvaline, L-valine) were able to inhibit most enzymes when present at high concentration. It was proposed that the mode of inhibition by these latter amino acids may occur via interaction at the site specific for allosteric inhibition. L-Valine at low concentration effected pronounced activation of the enzymes and was thusly assigned the role of allosteric activator, acting at a site distinct from that of L-isoleucine or L-threonine. Hemiselmis virescens was distinctly unique in that, unlike the other algal enzymes, it displayed two pH-activity optima. The investigation of this phenomenon was pursued in two ways (i) examination of enzyme response to various potential effectors (nucleotides, L-methionine, L-aspartate,^ L-cystathionine) at a pH intermediate between the two optima, (ii) examination of enzyme response to known effectors (L-valine, L-isoleucine) at the two pH optima. It was concluded from these studies that Hemiselmis virescens may produce a culture-dependent mixture of two threonine dehydratases, one of which is generally similar to the other algal enzymes, the other of which is insensitive to the usual allosteric regulation yet is not a standard biodegradative isozyme. / Land and Food Systems, Faculty of / Graduate

Until recently, few collections of the marine brown alga Phaeostrophion irregulare S. et G. had been made, little was known of its ecology, and virtually nothing of its life history. The main objectives of this investigation were to study the life history and major factors influencing growth and distribution of this species. Laboratory and field investigations were conducted during 1961-196i4. Life history studies were performed in the laboratory by culturing zoospores under constant environmental conditions. The growth of cultured germlings and the photosynthetic response of the laminate plants from the field were recorded under different temperatures, salinities, nutrients, and light conditions. The tolerance of laminate plants and germlings to extremes of temperature, salinity, and desiccation was also determined in the laboratory. The growth and reproduction of in situ plants at Glacier Point, British Columbia were correlated with temperature, salinity nutrients, tides, sand and various meteorological conditions at that locality. Life history studies were conducted at Glacier Point by observing the succession of germlings on denuded transects and by transplanting laboratory cultured germlings into the field. The laminate thallus of P. irregulare sometimes bears both unilocular and plurilocular sporangia at the same time. Previously, only unilocular sporangia were reported in this plant. Zoospores from the unilocular sporangia (unispores) and plurilocular sporangia (plurispores) develop identicallys, and each is capable of producing a laminate thallus directly or after a succession of filamentous and discoid plethysmothalli. The "direct-type" of development of the zoospores (unispores) from the unilocular sporangium is probably due to a suppression of meiosis in the unilocular sporangium. Morphological and cultural evidence is presented to support this hypothesis, although no cytological evidence was obtained. At Glacier Point, P. irregulare is restricted to sandy areas, and the greatest number of plants occur where large fluctuations of sand occur annually. The plants are regularly buried four to six months per year, and their growth and reproduction is limited to the period when sand is absent. Competition with other plants probably accounts for the occurrence of P. irregulare in sandy areas, since it will grow in rocky areas if other algae are eliminated. The period of maximum growth (February to April) is associated with a corresponding increase in light intensity and water temperature in this area. After April, growth in non-tide pool populations decreases much more rapidly than growth of tide pool populations, because of the increased exposure of plants to desiccation during daylight. A period of decreased growth for tide pool plants occurs in May to June; this decrease probably results from high surface water temperatures, high light intensities, or a combination of both. The morphology of the laminate plants of P. irregulare is extremely variable and the range of variability observed at Glacier Point overlaps that described for P. australe from Callifornia. P. australe is considered to be a growth form of P. irregular, and is therefore a taxonomic synonym of P. irregulare, Distributional evidence also supports this conclusion. The known range of P. irregulare extends from Point Conception, California to Khantaak Island, near Yakutat, Alaska. Temperature is considered to be the primary factor controlling its gross distribution. Nitrate and phosphate deficiency may partially restrict the distribution of P. irregulare south of Point Conceptions, California. The sporadic distribution of P. irregulare on the Pacific Coast is correlated with the presence of sand, and local conditions are most important in determining its regional distribution. Experimental studies show that P. irregulare is well adapted to a sandy habitat, and several features are discussed to explain this adaptation. The laminate plants and germlings of P. irregulare tolerate a wider range in temperature and salinity in culture than that to which they are subjected in nature. However, the laminate plants and germlings of P. irregulare are very sensitive to desiccation; under experimental conditions both tolerate less desiccation than that to which they are subjected under natural conditions. / Science, Faculty of / Botany, Department of / Graduate

A comparative study was made between two similar red algal endophytes, Audouinella porphyrae (Drew) Garbary and Audouinella vaga (Drew) Garbary, Hansen et Scagel, (Acrochaetiaceae, Acrochaetiales) and their red algal hosts Porphyra spp. and Pterosiphonia bipinnata, respectively. Both endophytes have axial, stellate chloroplasts with a central pyrenoid and reside in their host's cell walls, producing erect portions outside the host that may bear monosporangia. The endophytes were cultured "free" from their hosts and morphological and cytological features of the free-living forms were compared with field material. Although the two endophytes differ significantly in cell dimensions and branching patterns, the free-living forms do not retain these differences. Cell dimensions, branching patterns and developmental patterns are identical in the two free-living forms. Asexual reproduction with regeneration by monospores was observed. Sexual reproduction was not observed in either endophytic or free-living forms of the endophytes. Free-living forms were used for re-infection and cross-infection experiments. Under all experimental conditions, the endophytes showed only epiphytic growth. The hosts seem to have some effect on both of the endophytes. Epiphytes, Audouinella porphyrae and A. vaga were not selective and grew on both hosts, Porphyra torta and Pterosiphonia bipinnata. Both epiphtyes growing on blades of Porphyra tended to branch and have more extensive prostrate portions (3-5 cells) whereas both epiphytes on Pterosiphoni a bipinnata tend not to branch and have only 1-2 cells in the prostrate portions. Ultrastructural studies of both endophytes showed typical florideophycean features. Ultrastructural features of field material of the two endophytes were similar and free-living, cultured endophytes were similar to field material. A large vacuole was observed in sections of the field material of both prostrate and erect portions whereas this was not observed in cultured material. Based on the results of this study it is proposed that the two endophytes are conspecific. Audouinella vaga is referred to synonymy in Audouinella porphyrae (Drew) Garbary, Hansen et Scagel. / Science, Faculty of / Botany, Department of / Graduate