In the previous part of this review, the need for a reliable index of the eating quality of milled rice was discussed. In this paper, compositional and physicochemical criteria are examined for their potential usefulness as quality indicators. Kernel shape is shown to be unreliable as the sole quality criterion. Itappears that the only reliable test available is based on measurement of amylose content, and it is proposed that such a test, in combination with a determination ofkemel shape, would provide asatisfactory indication of the eating quality of milled rice.

Abstract: Techniques for adapting evaluation methods to satisfy the needs of nonformal education are designed for use by the program practitioner. The problems associated with traditional evaluation procedures are described: a focus on outcomes rather than process improvement; a lack of applicability to the nonformal context; and the creation of a costly and disruptive situation within the program. Existing adaptations to various methodologies are discussed in terms of formative evaluation, nonformal education settings, and practitioner use. The criteria for selecting the adaptive process are based on: skill, time, and cost factors; amount of disruption engendered; degree of utility; setting of practical standards; allowance for non-quantifiable indicators; and amount of flexibility to meet program constraints. The approaches to adapting evaluation procedures may be incremental, extractive, or participative, or they may be decision-making or option-oriented. Other considerations include creating a favorable atmosphere and training for practitioner evaluation.j).

Certain soluble proteins are believed to be closely associated with cold tolerance. The objectives of this work were to determine whether the proteins exhibited dehydrogenase activity and if there were qualitative and/or quantitative differences in dehydrogenases between hardened and nonhardened plants. Cold-tolerant ‘Vernal’ and cold-sensitive ‘Sonora’ alfalfa (Medicago sativa L.) plants were grown for 66 days under simulated summer (non-hardening) and winter (hardening) conditions, using growth chambers, and were assayed for the levels of cold tolerance developed at three freezing temperatures (−6, −8, and −10 C). To determine differences in dehydrogenases, soluble proteins were separated from extracts of crown and root tissues by polyacrylamide disc gel electrophoresis. Localization of dehydrogenases on gels and densitometric scanning of zymograms indicated that activities of glutamate, lactate, isocitrate, glucose-6-phosphate, 6-phosphogluconate, nicotinamide adenine dinucleotide (NAD) malate and nicotinamide adenine dinucleotide phosphate (NADP) malate dehydrogenases were high in both cultivars exposed to hardening and were generally highest in Vernal. Percent increases for winter over summer levels of glutamate, lactate, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases were large compared with those of isocitrate, NAD-malate, and NADP-malate dehydrogenases. Moreover, the magnitude of change in enzyme activity between summer and winter plants also was influenced by extractant (distilled water, pH 7 or 0.10 M tris-HCl, pH 7) and varied quantitatively according to the solubility of the dehydrogenases in the two extractants. Enzyme solubility differences related to cultivar or environmental influences and cold tolerance were also observed, especially for isocitrate dehydrogenase. Large quantitative differences in glucose-6-phosphate and lactate dehydrogenase activities and substantial increases in isocitrate and 6-phosphogluconate dehydrogenases localized within gel column regions 7 and 8 of zymograms developed from winter samples implied a close relationship of these enzymes to cold tolerance. Forms of lactate, glucose-6-phosphate, and isocitrate dehydrogenases were present in hardened tissues that were not present in un-hardened tissues. It is concluded that the observed differences in dehydrogenasees between hardened and non-hardened plants are major indicators of the cold tolerant state. Based on these and past studies, the reactions analyzed by representative hydrolytic and dehydrogenase enzymes may serve as a working hypothesis for future studies concerning the mechanics of induction and the suspected catenary nature of the hardening process.

Dissertation (MSc)--University of Pretoria, 1978. | Lake Chrissie represents a shallow, brackish, inland water body which can be described as a lake on the basis of its size and permanent character. A relatively small amount of algological sutdies have been done on inland water bodies of Southern Africa. The present study, therefore, contributes to our knowledge regarding the occurrence and distribution of algal species in South African waters. Algal communities in the littoral zone of Lake Chrissie (represented primarily by brackish water conditions) as well as in inflowing streams and springs were regularly sampled over a period of two years. The different algal species in each sample were identified and studied in the laboratory with the aid of the light microscope. Counts of the various identified species were made, the results of which were used to estimate the percent composition of the communities. Superficial observations were also made on some environmental conditions. The study resulted in the identification of some 1 100 algal species in the Lake Chrissie water complex (comprising fresh, brackish and so-called mixed water environments). Representatives of the following taxa were found at the various sampling stations. The number of species per taxon is represented in brackets. : Cyanophyceae (253), Euglenophyceae (169), Pyrrophyceae (28), Chrysophyceae (9), Xanthophyceae (10) and Chlorophyceae (665). According to the literature, about 50, 20, 2, 1, 4 and 240 respectively, have been known to occur in South Africa. Two new Cyanophyceae species, one variaty, three new Chlorophyceae species and two new Chlorphyceae variaties are being described. Representatives of the Cyanophyceae, Chrysophyceae, Euglenophyceae, Pyrrophyceae, and Chrysophyceae were found in brackish water environments. The composition of the algal communities varied according to the location of the littoral area (northern or southern banks) and the season. Short term freshening of the littoral water at some sampling stations resulted in an increase in the number of algal species present. Fewer algal species (46) occurred in the southern littoral area than in the northern littoral area (1 07). The brackish water communities were dominated by benthic Stigeoclonium species. The northern littoral area was dominated by S. tenue, the eastern and western littoral areas by S. /ubricum, while the southern littoral area was dominated by S. aestivale. The fresh water environments are diverse in algal species and were represented by Cyanophyceae, Chlorophyceae, Euglenophyceae, Pyrrophyceae, Chrysophyceae, and Xanthophyceae. The dominant algal populations consisted of filamentous species, namely Mougeotia/Oebarya sp., Oedogonium hirni and Staurastrum orbiculare var. depressum. At a few sampling stations, which originally were thought to be brackish in nature, fresh water conditions existed, for apparently long enough periods during the rainy season resulting in algal communities sometimes dominated by fresh water species and sometimes dominated by brackish water species. Observations based on these communities made it possible to conclude that the Xanthophyceae and certain Desmidiaceae representatives could be regarded as indicators of freshwater conditions. Superficial observations on environmental conditions indicated that pH and temperature played an important role in changes and differences in the composition of the algal communities of the Lake Chrissie water complex. | Chrissiesmeer verteenwoordig 'n vlak brakwater binnelandse watermasse wat vanwee sy grootte en standhoudendheid as 'n meer beskryf kan word. Betreklik min algologiese studies is tot dusver op binnelandse watermasses van Suidelike Afrika gedoen sodat hierdie studie 'n bydrae tot kennis aangaande die voorkoms en verspreiding van algsoorte in Suid-Afrikaanse waters maak. Alggemeenskappe van die oewersone van Chrissiesmeer self (verteenwoordig hoofsaaklik brakwatertoestande) sowel as van inlope en fonteine is oor 'n periode van twee jaar gereeld versamel. Verskillende algsoorte van elke versameling is in die laboratorium met behulp van die ligmikroskoop gei'dentifiseer en bestudeer. Tellings is van die verskiilende gei'dentifiseerde soorte gemaak, die resultate waarvan vir die berekening van die persentasie samestelling van die gemeenskappe gebruik is. Redelik beperkte waarnemings is ook op sommige omgewingstoestande wat by die verskillende versamelpunte geheers het, gemaak. Die studie het aan die lig gebring dat daar ongeveer 1 100 algsoorte in die water van die Chrissiesmeerwaterkompleks (bestaande uit vars- brak- en sogenaamde gemengde wateromgewings) voorgekom het. Verteenwoordigers van die volgende taksons is by die verskillende versamelpunte aangetref (die getal tussen hakies verteenwoordig die aantal spesies wat tot die betrokke takson behoort). Cyanophyceae (253), Euglenophyceae (169), Pyrrophyceae (28), Chrysophyceae (9), Xanthophyceae (10), en Chlorophyceae (665). In dieselfde volgorde is slegs ongeveer 50, 20, 2, 1, 4 en 240 soorte reeds voorheen volgens die literatuur wat nagegaan is in Suid-Afrika aangetref. Twee nuwe Cyanophyceae-spesies en een varieteit, drie nuwe Chlorophyceae spesies is gevind en beskryf terwyl twee nuwe Chlorophyceae varieteite ook beskryf is. Verteenwoordigers van die Cyanophyceae, Chlorophyceae, Euglenophyceae, Pyrrophyceae en Chrysophyceae is in brakwateromgewings aangetref. Die samestelling van die alggemeenskappe het volgens oewer (byvoorbeeld noordelik en suidelik) van seisoen tot seisoen gewissel. Kortstondige vervarsing van die oewerwater by sommige versamelpunte het 'n vermeerdering van die teenwoordige algsoorte tot gevolg gehad. Die suidelike oewer was armer aan algsoorte (46) as die noordelike oewer ( 140). Die brakwatergemeenskappe is deur bentiese Stigeoclonium-soorte oorheers. Die noordelike oewer is deur Stigeoclonium tenne oorheers, terwyl die oostelike en westelike oewers deur S. lubricum en die suidelike ower deur S. aestivate oorheers is. Die varswateromgewings is baie ryk aan algsoorte wat deur Cyanophyceae-, Chlorophyceae-, Euglenophyceae-, Pyrrophyceae-, Chrysophyceae- en Xanthophyceae-spesies verteenwoordig is. Die dominante algbevolkings is deur die filamentvormige soorte, naamlik Mougeotia/Debarya sp., Oedogonium hirni en Staurastrum orbiculare van depressum, uitgemaak. By enkele versamelpunte wat vanwee hulle posisie aanvanklik as brakwaterpunte beskou is, het varswatertoestande gepaardgaande met die reenseisoen klaarblyklik vir 'n lang genoeg periode geheers sodat die alggemeenskap soms oorwegend uit brakwatersoorte en soms oorwegend uit varswatersoorte bestaan het. Op grond van waarnemings wat op hierdie gemeenskappe gemaak is, is afgelei dat Xanthophyceae- en sommige Desmidiaceae-verteenwoordigers as aanwysers van varswatertoestande beskou kan word. Die oppervlakkige waarnemings wat op omgewingstoestande gemaak is dui daarop dat pH- en temperatuurtoestande 'n belangrike rol by veranderings en verskille in die algbevolkingsamestelling van die Chrissiesmeerwaterkompleks speel. | Plant Science | MSc | Unrestricted