Showing items 1 - 20 of 97

Your selections:

A contribution to the benthic biology of some southern African lakes

  • Authors: Boltt, R E
  • Date: 1969
  • Subjects: Aquatic biology -- Africa, Southern Benthos -- Africa, Southern Lake animals -- Africa, Southern
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5836 , http://hdl.handle.net/10962/d1009521
  • Description: The benthos of Lake Sibayi, Lake Nhlange, Lake Shengesa and Lake Sifungwe has been sampled by means of a van Veen grab of bite area 0.225m². Except for Lake Shengesa, the substrates of the lakes have been investigated visually by SCUBA divers. Some quantitative sampling, using underwater techniques, has been carried out in Lake Sibayi. In general, the substrate of the lakes consisted of two types, either fine sand with an average particle size of 3.2 phi, or mud with a median phi value of less than 6. The sandy substrata was usually rich in fauna, and the mud usually poor. Lake Sibayi , which is freshwater (135 ppm Cl¯) has estuarine and freshwater species in the benthos. Some of the species, notably Grandidierella lignorum and Apseudes digitalis, show an uneven pattern of distribution with respect to depth. Lake Nhlange is a brackwater lake (3.4‰ salinity) and has mainly an estuarine fauna. Many of the species are different from those found in Lake Sibayi. There is some evidence that the benthic fauna of the lake has increased its range in depth in the years following a flood in January 1966. Only chironomid larvae were found in the benthos of Lake Shengesa. The greater part of the substrate of this lake consisted of a highly organic mud mainly derived from burnt grassland around the periphery of the lake. Lake Sifungwe, which is connected to Lake Nhlange, has a halocline at about 9 metres. The fauna of the benthos has more species than lake Nhlange. There is some evidence to suggest that LGC fauna invades deeper water in summer, and is driven into shallower water in winter because of the fluctuating level of anaerobic conditions below the discontinuity layer. The benthic fauna of the lakes has been compared with that of the estuaries reported on by the Cape Town Ecological Survey. experimental studies on G. lignorum, a species present in Lake Sibayi, suggested that the physiological responses of material from an estuary normally at 35‰ salinity (Kowie River estuary) and from lakes which are normally of low salinity (Groenvlei 2.5‰ salinity, Lake Sibayi) were not different. Studies on substrate choice, and pressure, indicated that these factors do not affect the distribution pattern of G. lignorum in the substrate. Studies on light orientation responses and the effects of rates of carbon dioxide increase of about 20 mm HgC0₂/hr or more, suggest that these may be the principle factors affecting the distribution of G. lignorum in the benthos of Lake Sibayi. Some supporting evidence for the presence of changing pC0₂ has been found. A discussion of the importance of dynamic events at the substrate/water interface is given.
  • Full Text:
  • Date Issued: 1969

A critical investigation of the problems of teaching poetry to English-speaking pupils in South African senior schools

  • Authors: Durham, Ken
  • Date: 1969
  • Subjects: Poetry -- Study and teaching (Secondary) -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2293 , http://hdl.handle.net/10962/d1011609 , Poetry -- Study and teaching (Secondary) -- South Africa
  • Description: This thesis is a study of the problems of teaching poetry to English speaking pupils at South African senior schools. It is a study of what is generally agreed to be 'a peculiarly difficult department of teaching' Reeves 1958. Some would go as far as to suggest that the teaching of poetry is the most difficult aspect of any school subject : "No topic in the school curriculum has so many pitfalls as the teaching of poetry in the classroom: it is easier to go astray in attempting to promote aesthetic responses to a poem than in any other kind of lesson. 'Currey {19S8) p. 126.' If one may judge too by the number of complaints from a large body of teachers (see Chapter Four) about the difficulty of teaching poetry successfully the assessments given by Reeves and Currey appear to be well- founded. Additional weight is given by some of the attitudes of pupils themselves towards poetry and the poetry lesson (see Chapter Three). Further confirmation is evident at Teachers' Conferences and from examiners' reports that examination questions on poetry are often among the most badly answered and the least popular of all questions set. Even more significant, perhaps. were the responses from two separate graduate student teacher groups (U.E.D. English Method classes, Rhodes University 1965, 1967). When asked at the beginning of the course to name the one type of English lesson they felt least confident in handling, 42 of the 64 student teachers answered, 'The poetry lesson'. Into. p. 1.
  • Full Text:
  • Date Issued: 1969

A geographical study of the Cape Midlands and Eastern Karoo area with reference to the physiography and elements of land use

  • Authors: Badenhorst, J J
  • Date: 1969 , 2013-11-14
  • Subjects: Land use -- South Africa , Geomorphology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:4867 , http://hdl.handle.net/10962/d1007581 , Land use -- South Africa , Geomorphology -- South Africa
  • Description: The subject has been approached in the conventional geographic manner in successive chapters, Relief, Geology, Soil, Climate, etc. In practice, the relationship between geographic factors and land use is so close that it is usually very difficult to separate the one from the other. When there is any reference to a specific relationship in any chapter, it must be borne in mind that one must always take the other geographic factors into account. In this study the stress falls on an evaluation of the present land use. Even if there is no recommendation regarding the way in which the land should be used, this survey can still be used as the basis for future planning. Intro. p.viii , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
  • Full Text:
  • Date Issued: 1969

Albany Rugby Football Club 1st XV, 1969

  • Date: 1969
  • Subjects: Rugby football -- South Africa -- Eastern Cape -- Photographs , Albany Rugby Football Club -- Photographs
  • Type: still image
  • Identifier: http://hdl.handle.net/10962/49799 , vital:25926 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/M 6694
  • Description: Albany Rugby Football Club 1st XV 1969, 1st XV – 1969, Team photograph with rugby/football players, in rugby uniform, Group photograph, Black and white photograph, Outdoor photograph, Treasurer, Club Captain, President and Coach wearing suits, Captain holding rugby ball with “1969” on it, Players standing with arms by side, Players sitting with arms crossed, Players sitting on the grass with hands in lap, Team standing and sitting in front of tree and on grass, Building in the background, Back Row (left to right): J. Place (Treasurer), D. Phillipson, D. Pohl, B. O’Reilly, A. Read, W. Fourie, D. Klaasen, A. E. Timm (Club Captain), Middle Row (left to right): B. Green, E. Olivier, H. Blomfield (President), D. Emslie (Captain), B. Mills (Coach), B. Letcher, A. Le Roux, Sitting (left to right): L. Crous, C. Reed. Insets: C. Warren, M. Dunn.
  • Full Text: false
  • Date Issued: 1969

Albany Rugby Football Club 1st XV, 1969

  • Date: 1969
  • Subjects: Rugby football -- South Africa -- Eastern Cape -- Photographs , Albany Rugby Football Club -- Photographs
  • Type: still image
  • Identifier: http://hdl.handle.net/10962/49837 , vital:25929 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/M 6695
  • Description: Albany Rugby Football Club 1st XV 1969, 1st XV – 1969. Team photograph with rugby/football players, in rugby uniform, Group photograph, Black and white photograph, Outdoor photograph, Treasurer, Club Captain, President and Coach wearing suits, Captain holding rugby ball with “1969” on it, Players standing with arms by side, Players sitting with arms crossed, Players sitting on the grass with hands in lap, Team standing and sitting in front of tree and on grass, Building in the background, Back Row (left to right): J. Place (Treasurer), D. Phillipson, D. Pohl, B. O’Reilly, A. Read, W. Fourie, D. Klaasen, A. E. Timm (Club Captain), Middle Row (left to right): B. Green, E. Olivier, H. Blomfield (President), D. Emslie (Captain), B. Mills (Coach), B. Letcher, A. Le Roux, Sitting (left to right): L. Crous, C. Reed, Insets: C. Warren, M. Dunn.
  • Full Text: false
  • Date Issued: 1969

Albany Rugby Football Club 1st XV, 1969

  • Date: 1969
  • Subjects: Rugby football -- South Africa -- Eastern Cape -- Photographs , Albany Rugby Football Club -- Photographs
  • Type: still image
  • Identifier: http://hdl.handle.net/10962/49846 , vital:25931 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/M 6696
  • Description: Albany Rugby Football Club 1st XV 1969, 1st XV – 1969, Team photograph with rugby/football players, in rugby uniform, Group photograph, Black and white photograph, Outdoor photograph, Treasurer, Club Captain, President and Coach wearing suits, Captain holding rugby ball with “1969” on it, Players standing with arms by side, Players sitting with arms crossed, Players sitting on the grass with hands in lap, Team standing and sitting in front of tree and on grass, Building in the background, Back Row (left to right): J. Place (Treasurer), D. Phillipson, D. Pohl, B. O’Reilly, A. Read, W. Fourie, D. Klaasen, A. E. Timm (Club Captain), Middle Row (left to right): B. Green, E. Olivier, H. Blomfield (President), D. Emslie (Captain), B. Mills (Coach), B. Letcher, A. Le Roux, Sitting (left to right): L. Crous, C. Reed, Insets: C. Warren, M. Dunn.
  • Full Text: false
  • Date Issued: 1969

An analysis of Wesleyan missionary strategy in the eastern districts of the Cape Colony and "Caffreland" between 1823 and 1838, and an attempt to determine how far it reacted to government policies in the Cape

  • Authors: Duff, Allen Ernest George
  • Date: 1969
  • Subjects: Wesleyan Methodist Missionary Society , Missions -- South Africa -- Cape of Good Hope -- History -- Sources , Cape of Good Hope (South Africa) -- History -- 1795-1872
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:1250 , http://hdl.handle.net/10962/d1011606 , Wesleyan Methodist Missionary Society , Missions -- South Africa -- Cape of Good Hope -- History -- Sources , Cape of Good Hope (South Africa) -- History -- 1795-1872
  • Description: The purpose of this thesis has been to trace and examine the development of Wesleyan attitudes, and the actions which resulted therefrom towards the task of the evangelisation of the eastern districts of the Cape Colony and "Caffreland". These attitudes were conditioned throughout by the fact that they held certain religious principles as paramount. It is an attempt to clarify what was involved on the ecclesiastical side in this period of Wesleyan and South African history. A considerable amount of attention has been given, by various writers, to the history of the south-eastern area of South Africa in the first half of the nineteenth century. Some works have either been concerned with the more general history of the time or with the position of all the missionaries within the total political sphere. Others have concentrated on the Wesleyans particularly, either in a very general sense or in relation to one particular event, or the later decades or this half century. The period 1823 to 1833 was chosen because it covered the period of the origin of Wesleyan strategy and its first distinct phases. Where after it may be considered to have reached full maturity and become the basis of all future action in the succeeding decades. Wesleyan strategy was, to a large extent, a reaction to government policies and requires, throughout, such a consideration. The Wesleyan Missionary Society was chosen, not because on any denominational affiliations, but because of the part which it played in these areas during that time and has since played in the annuals of eastern Cape history. The approach has been to present the relevant documents in chronological order. This was done to emphasise the development over the years. Chapters have consequently been divided according to the stages or phases of this development. It has meant that subsidiary question which arise from this development have not been dealt with separately, but simply referred to as they occur. One point remains. Wesleyan correspondence from the Eastern Cape between 1837 and 1857 has disappeared from the archives of the Methodist Missionary Society in London. All attempts to trace these letters have proved futile. Consequently, it was necessary to reproduce a couple of quotes from letters contained in this correspondence which is referred to by D. Williams and C. Roxborough who had access to this material.
  • Full Text:
  • Date Issued: 1969

An econometrical estimation of the demand for money in South Africa : the long-run function during the period 1918-60

  • Authors: Maxwell, Thomas
  • Date: 1969
  • Subjects: Econometrics Keynesian economics Demand for money -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:1065 , http://hdl.handle.net/10962/d1007618
  • Description: Introduction: In recent years there has been a marked upsurge in the output of literature dealing with the demand for money, but with the exception of the North American Continent, empirical research has lagged distressingly far behind the voluminous output of theory. This dearth of empirical results has had a restrictive influence. Since any of the controversial points which are being disputed by theoreticians can only be resolved by recourse to empirical methods. The restriction of empirical research to the North American Continent has further meant that the various points under dispute have had only a limited qualification and consequently monetary theorists have had no indication as to the universalizability of their conclusions. There is thus a great need for empirical studies in other countries so that the validity of the rival theories can be tested under different conditions. It was with these thoughts in mind that the present study was undertaken. Its objectives are strictly national and no pretense of strict international comparability is made. Further, great care has been taken to avoid the pitfall so beloved of econometricians, the fallacy of reduction wherein strictly limited results are uncritically universalized. Thus no attempt has been made to draw conclusions which will have universal validity. The theoretically vital points which are going to be examined in the light of South African experience are: 1. The feasibility of distinguishing idle from active balances, and if this proves possible, the determination of the wealth and interest elasticities of these balances; 2. Dropping the explicit distinction between idle and active balances to (a) determine the role of interest rates, (b) determine the appropriate constraint on the demand function, (c) determine what effect different definitions of money have on (a) and (b); 3. To examine the stability of the demand function over time. Truth is, of course, many-sided and any uniform presentation can only aspire to present a one-sided picture, just like a photograph cannot hope to do justice to the full grandeur of nature, merely presenting a one-dimensional representation of a many dimensioned object. In spite of this restriction which is inherent in all econometrical studies, this one-sided picture seems to be justified in view of the lack of any unified and coherent treatment of the demand for money in South Africa.
  • Full Text:
  • Date Issued: 1969

An historical survey of the organs, organists and music of St. George's Cathedral, Cape Town, from 1834 to 1952

  • Authors: Smith, Barry, 1939-
  • Date: 1969
  • Subjects: St. George's Cathedral (Cape Town, South Africa) , Organ (Musical instrument) -- South Africa -- Cape Town -- History , Organists
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2665 , http://hdl.handle.net/10962/d1004745 , St. George's Cathedral (Cape Town, South Africa) , Organ (Musical instrument) -- South Africa -- Cape Town -- History , Organists
  • Description: From Introduction: The first recorded Church of England service at the Cape took place in 1749, but for almost a century after that date Anglicans had no place of worship of their own. From about 1807 onwards the Groote Kerk in Adderley Street was regularly lent to the Chaplain on Sundays and the Kerkraad even allowed their bells to be rung to inform 'the British that it was time for their service'. In October 1827, for the first time in history, a bishop of the Church of England visited Cape Town. This was Dr. J.T. James, Bishop of Calcutta, who landed for a few days on his first voyage to India and was met by the Governor and his staff in great state. A meeting was held at which Bishop James was present and the eighteen gentlemen discussed proposals for the building of an English Church in Cape Town. "It was proposed that the building should hold at least 1,000 people. The Bishop said that the Home Government would grant ground and half the expenses... He reminded them of their obligation to the Dutch Church, who for so many years had allowed them to use their sanctuary, and he exhorted them to be active and persevering and remain attached to the doctrine and discipline of the Church of their forefathers, that venerable Church based on the foundation of Christ and His Apostles." As a result of t his meeting the Governor gave the site in the Gardens (at the foot of the Avenue) on which St . George's Cathedral now stands, and the site was consecrated by Bishop James on October 23rd, just before he sailed for Calcutta . "But after his departure the glow faded away, difficulties and quarrels appeared... and the scheme was shelved for two years." However, on St. George's Day, 23rd April 1830, the foundation stone of St. George's Church was laid by the Governor, Sir Lowry Cole,with military and Masonic honours. A triumphal arch was erected and troops lined the streets through which the procession was to pass. The name of the street at the head of which the Cathedral stands was changed from Bergh Street to St. George' s Street, and the contract was exclusive of enclosure, gates, bells and organ, but including pulpit, reading and clerk 's desks and all the work of the altar."
  • Full Text:
  • Date Issued: 1969

An investigation into chemical and biological assays of new compounds from aloes

  • Authors: Mapp, R K
  • Date: 1969
  • Subjects: Medicinal plants -- Research -- South Africa , Botanical chemistry , Aloe -- Analysis , Aloe -- Research -- South Africa , Aloe , Aloin
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3850 , http://hdl.handle.net/10962/d1012830
  • Description: The drug aloes has been known since earliest times and is mentioned in the Ebers papyrus of circa 1,500 B.C. Alexander the Great is reported to have sent a commission to Socotra to investigate the aloes grown there. The chemical composition of aloes is complex, and being of plant origin, subject to variation. Both the complexity of the chemical constituents and their biological variation has resulted in a very large volume of conflicting material being published on this drug export. Since aloes is used as a purgative for both human and veterinary use, it is obviously important that the dosage and consequently the active constituents, should comply to an accurate means of standardisation. To date, despite extensive world wide research into this drug such standardisation has not been achieved. Even the methods used for the assay of the principal constituent, aloin, vary considerably in their results, and to complicate matters new chemical principles have been isolated from aloes in recent years. Consequently the purpose of this work has been to investigate the main chemical assay methods currently in use, and to determine which was the most accurate, and why discrepancies occurred in the selected assay methods. furthermore the results obtained by chemical assay have been compared with those obtained by biological assay in an attempt to correlate aloin content with purgative activity. Newly isolated compounds have been investigated biologically for the first time, and the biological assays of the resinous, glycosidal and other compounds of aloes have been performed. Intro. p.1-2.
  • Full Text:
  • Date Issued: 1969

An investigation into some aspects of Jovian decametric radiation

  • Authors: Hill, I. E.
  • Date: 1969
  • Subjects: Jupiter (Planet) , Radiation , Magnetosphere
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5552 , http://hdl.handle.net/10962/d1015034
  • Description: This thesis describes observations of the flne structure in Jovian decametric radiation made at Grahamstown during the 1967-68 apparition. It was found that pulses with duration less than 0.5 milliseconds were common during fine structure storms. The restrictions placed on the source for different theories of origin of the short pulses are discussed. The variation of the probability of occurrence from year to year is analysed on the assumption that the radiation is found in directions fixed with respect to the planet's magnetic field. It is concluded that there is a factor other than the declination of Earth and the Io effect which controls the probability of occurrence. A detailed analysis suggests a beam width of 3° in latitude at Jupiter but further work is necessary to check this.
  • Full Text:
  • Date Issued: 1969

An investigation into some aspects of the thin layer chromatographic assay of Pregnanediol with emphasis on the suitability of this method as a clinical laboratory routine

  • Authors: Paton, L T
  • Date: 1969
  • Subjects: Thin layer chromatography , Pregnanediol
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3853 , http://hdl.handle.net/10962/d1013023
  • Description: Pregnanediol (5B Pregnane- 3⋉- 20⋉- dial) is the chief urinary metabolite of progesterone, and as such is important in that variations in its concentration reflect variations in progesterone secretion. Estimations of pregnanediol concentration are therefore of considerable interest to the obstetrician and gynaecologist. Pregnanediol was first identified in the urine of pregnant women in 1929 by Marrian. Nearly ten years later Venning developed a method by which the glucuronic acid ester of pregnanediol could be extracted from the urine and its concentration gravimetrically determined. Numerous variations of the Venning theme were published in the next few years, each being claimed by its authors to be an improvement on the original. Most of these involved the estimation of the conjugated form, and it was a while before the advantage of estimating the hydrolysed aglycone was realized. Hydrolysis, when it was practised, resolved itself into two methods - namely, hydrolysis by heating the urine with a mineral acid, and enzymic hydrolysis by incubation with beta-glucuronidase. Acid hydrolysis, while producing a less clean hydrolysate, is more rapid and convenient than enzyme hydrolysis, and is used in the Klapper method which is presently the most widely used method in clinical studies. Klapper employs a double chromategraphic column separation of pregnanediol followed by colorimetric evaluation. Variations of Klapper's method have also appeared and not a few investigators have published comparisons of the various methods. Klapper himself compared his method to certain other methods and concluded that his was definitely superior. Of the accuracy of the Klapper method there is no doubt. Subsequent methods have proved more sensitive, but in terms of practicability Klapper's is the method of choice. As was pointed out with some complacency, "practicability is most satisfactory, one technician readily performing some twenty determinations in one week." In contrast to the flood of criticisms, comparisons, variations, claims and counter-claims which accompanied the publication of the abovementioned methods, the thin layer chromatographic method perfected by Waldi attracted very little attention. It is very much more rapid than all other existing techniques, is very sensitive, specific and of acceptable accuracy. In an attempt to ensure its usefulness for clinical and medical research laboratories, the Waldi method has been marketed in 'kit' form. It is intended primarily as a diagnostic aid in establishing pregnancy, and as such it might have enjoyed considerable application had it not been for the advent of the immunological method of pregnancy diagnosis which is very much more rapid. Nevertheless, the Waldi method, used purely as a means of assessing the pregnanediol content of the urine is extremely useful, and it is the purpose of this investigation to establish this usefulness, especially with respect to routine clinical investigations. The validity of some diagnoses which are based on pregnanediol assay results, is also investigated. As it is impossible to explain the significance or usefulness of a pregnanediol assay without first explaining the functions of progesterone, some time and space must be expended in a brief description, firstly, of the role played by progesterone in the phenomenon of the menstrual cycle, and secondly, of its vital importance in pregnancy. It must be realized that progesterone is only one of the many hormones involved in these events, but, in order to limit the introduction of extraneous detail, no mention is made of the other hormonal participants except when necessary for the understanding of the whole. It may be mentioned here that much of the evidence that was used for the elucidation of the functions and origins of progesterone, was derived from studies of its metabolite, pregnanediol.
  • Full Text:
  • Date Issued: 1969

Ann Anderson (Nash), with her parents and daughters in 1969

  • Date: 1969
  • Subjects: Class reunions -- South Africa -- Grahamstown -- Photographs Grahamstown Teachers' Training College (South Africa) -- Photographs
  • Type: Image
  • Identifier: http://hdl.handle.net/10962/17586 , vital:22262 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/A 2897_009
  • Description: Photograph of Ann Anderson (Nash), with her parents and daughters (and probably her husband) in 1969 , Leila Kerr (Linington) (Donor)
  • Full Text: false
  • Date Issued: 1969

Aspects of the ecology of piscivorous birds of Lake Kyle Rhodesia

  • Authors: Junor, F J R
  • Date: 1969
  • Subjects: Bird populations -- Zimbabwe , Water birds -- Zimbabwe
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5909 , http://hdl.handle.net/10962/d1015201
  • Description: [From Introduction]. From an early period in the lake's history research was undataken to determine the potential of Kyle as a source of edible fish, In such a study, knowledge of the number and weight of fish consumed by piscivorous birds would seem to be an obvious consideration. Accordingly special investigation was undertaken into the food requirements of fish eating birds which live in the lake area. The method employed, on this occasion, to obtain the required information has differed radically from that more generally used by investigators working with similar objects in view. The common practise has been to examine the stomach contents of a considerable number of birds of the same species, which have been destroyed in order to make information available.
  • Full Text:
  • Date Issued: 1969

Brenda Clark and Jackie Breer at Rag week, 1969

Changes in carbohydrate concentration and amylolytic activity in germinating maize

  • Authors: Breen, C M
  • Date: 1969
  • Subjects: Corn -- Research Corn -- Analysis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4251 , http://hdl.handle.net/10962/d1007680
  • Description: Changes in the concentration of some carbohydrates and in amylolytic activity have been followed during germination of Zea. Mays L. var. Hickory King and var. Early Pearl. Assay techniques have been developed which permitted assay of individual grains. Thus during the investigation both groups and individual grains were used as samples. The use of groups permitted control of assay technique. Length of radicle, coleoptile and lateral roots were recorded in order to permit quantitative estimation of correlation between growth and the concentration of the various carbohydrates. Initially, during the study of changes in the carbohydrate concentration in Hickory King grains, total reducing sugar, sucrose and dextrin concentrations were estimated. However, the results obtained for changes in dextrin concentration, although reproduceable, thereby indicating reliable assay technique, presented a confusing picture and, in view of the apparent importance of sucrose and reducing sugar concentration, assay of dextrin concentration was discontinued in a subsequent study of Early Pearl. Instead changes in total reducing sugar, sucrose and glucose concentrations were followed. The results revealed that there is very considerable variability in physiological activity between grains subjected to the same germination conditions. However, all, irrespective of variety, follow the same basic metabolic pattern during germination. The trends observed were: (i) Reducing sugar accumulates slowly during the first 72-96 hours germination, but thereafter accumulation is very rapid, although concentration may decrease towards the end of the gestation period. (ii) Glucose follows a similar pattern to reducing sugar, accumulating slowly during the early stages of germination, followed by a period of rapid increase in concentration, which may decrease towards the end of the germination period. (iii) Sucrose concentration in dormant grains is fairly high, but it decreases markedly during the first 96 hours germination. This is followed by a phase of sucrose accumulation. (iv) Dextrin concentration shows two peaks. Initial level is low, but it accumulates rapidly during the first 72 hours. The level decreases between 72 and 120 hours but increases when the germination period is increased to 192 hours, after which there is a marked decrease. It was impossible, from the data relating to the study of individual grains, to discern a trend in dextrin concentration. With the exception of dextrin, about which there is little information, the results are in general agreement with the literature. Investigation of correlation between the various carbohydrates and between these and growth revealed that: (i) reducing sugar concentration and growth are positively correlated ; (ii) glucose concentration and growth are positively correlated; (iii) sucrose and reducing sugar concentrctions are negatively correlated during the initial stages of germination; (iv) sucrose and glucose concentrations are negatively correlated during early germination; (v) glucose and reducing sugar are positively correlated; (vi) in general, correlation between growth and concentration of the carbohydrates studied, decreases during the later periods of germination. These observations suggested that growth was, at least during the early stages of germination, dependent on the level of reducing sugar, and more particularly on the level of glucose, and that sucrose is the principal source of reducing sugar during this period. The relationship between amylase activity (total alpha- and beta-amylase activity) and reducing sugar concentration tends to be curvilinear, which suggests that amylolytic activity produces relatively little reducing sugar during early gennination, even though amylase activity and growth may be positively correlated. The results suggest, contrary to the observations of previous workers, that alpha-amylolytic activity may be present in dormant grains and that maize is not characterised by low levels of beta-amylase activity during germination. From the observations it is concluded that the initinl accumulati on of reducing sugar is the result of sucrose hydrolysis, and therefore sucrose is an importnnt metabolite durjng early germination. Amylolytic activity contributes little reducing sugar durlng the initia1 stages of germinatIon but that after approximately 72 hours it represents the major source of reducing sugar.
  • Full Text:
  • Date Issued: 1969

Crowds on the street during Rag week, 1969

David Smit and Judy Mullins in the Rag Band costumes, 1969

Erythrina caffra - Kaffirboom

Erythrina caffra - Kaffirboom

  • Disclaimer
  • Privacy
  • Copyright
  • Contact