The length and frequency of stomata on leaf surfaces were examined as rapid techniques for future identification of ploidy level of Acacia mearnsii (de Wild). Diploid (2n = 2x = 26) and tetraploid (2n = 4x = 52) plants were germinated from chipped seed at 25°C and grown under nursery conditions. After one month, measurements showed that the mean stomatal length was 27.17 ± 0.474 µm for diploids and 40.24 ± 0.521 µm for tetraploids and these differed significantly from each other (P < 0.001). The frequency of stomata per leaf surface was shown to decrease significantly (P < 0.001) as the ploidy level increased, with a mean of 22.11 ± 0.495 for diploids and 10.26 ± 0.495 for tetraploids. It was concluded that stomatal length and stomatal frequency are rapid indirect methods to identify ploidy level in black wattle. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 177–181.

Many publications are available on the topic of compliance with infection prevention and control in oral health-care facilities all over the world. The approaches of developing and developed countries show wide variation, but the principles of infection prevention and control are the same globally. This study is a systematic review and global perspective of the available literature on infection prevention and control in oral health-care facilities. Nine focus areas on compliance with infection-control measures were investigated: knowledge of infectious occupational hazards; personal hygiene and care of hands; correct application of personal protective equipment; use of environmental barriers and disposable items; sterilisation (recirculation) of instruments and handpieces; disinfection (surfaces) and housekeeping; management of waste disposal; quality control of dental unit waterlines, biofilms and water; and some special considerations. Various international studies from developed countries have reported highly scientific evidence-based information. In developed countries, the resources for infection prevention and control are freely available, which is not the case in developing countries. The studies in developing countries also indicate serious shortcomings with regard to infection prevention and control knowledge and education in oral health-care facilities. This review highlights the fact that availability of resources will always be a challenge, but more so in developing countries. This presents unique challenges and the opportunity for innovative thinking to promote infection prevention and control.

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A cytotaxonomic investigation was undertaken to assess the taxonomic status of the grasses Alloteropsis semialata subsp. eckloniana and A. semialata subsp. semialata, distinguished because of a C3 photosynthetic pathway in subsp. eckloniana and a C4 pathway in subsp. semialata. Of the 30 analysed specimens of population A, 14 (46.7%) were diploid, 14 (46.7%) hexaploid, one octoploid (3.3%) and one dodecaploid (3.3%). Of the 21 specimens of population B, 14 (66.7%) were diploid, three (14.3%) hexaploid and four (19.0%) octoploid. All the diploids belonged to subsp. eckloniana, while all the polyploids belonged to subsp. semialata. Meiosis of the diploids appeared normal, with nine bivalents and a mean metaphase I chiasma frequency of 12.7 per cell. The hexaploids displayed a large range of chromosome pairing associations, although a high percentage of bivalents was recorded (89.9%). Three of the hexaploids showed 100% bivalent pairing, but the largest multivalent found in other hexaploids was a hexavalent pairing. The three octoploids analysed had 93.5% bivalent pairing. B chromosomes were found in five diploids, two hexaploids and one octoploid. Slow‐moving bivalents, two in the diploids and up to four in the polyploids segregated late at anaphase I in most specimens.

Two South African Pyrgomorpha species have reduced chromosome numbers, due to centric fusions between the largest autosomes and the medium and small autosomes. P. rugosa has 2n o" = 1 I(XO) (4 pairs of submetacentric and 1 pair of acrocentric autosomes) and P. granulata has 2n~ = 13(XO) (3 pairs of submetacentric and 3 pairs of acrocentric autosomes). A third South African species has a typical Pyrgomorphidae number of 2n o ~ --19(XO) (acrocentrics). The mean chiasma frequency of the 2n(5 = 19 species is higher than that of the other two, although the frequencies of distal chiasmata in all three are similar. The recombination potential of the two species with lower chromosome numbers has been reduced, due to fewer crossovers in comparison to the 2no ~ = 19 species, as well as to independent assortment.

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Dairy farms in central South Africa depend mostly on groundwater for domestic needs and dairy activities. Groundwater samples were collected from 37 dairy farms during 2009 and 2013. Sixteen water quality parameters were tested and compared to the standard. Four parameters in 2009 and six in 2013 exhibited 100% compliance with the standard. Nitrate, Escherichia coli and total coliforms showed relatively low compliance across farms and years. Almost all farms were noncompliant for hardness in both sampling years. T-tests revealed significant changes from 2009 to 2013 for pH (t = 2.580; p = 0.006), hardness (t = 2.197; p = 0.016) and potassium (K) (t = 1.699; p = 0.0468). For hardness, approximately 45% of the farms in 2009, and 57% in 2013, posed a health risk to sensitive consumers. More than 50% of the farms in both years demonstrated levels of nitrates that could pose a health risk, particularly for babies. High levels of coliforms and E. coli were found, indicating a health risk for clinical infections in consumers. The number of farms presenting 3 or more parameters with a health risk more than doubled from 13.5% in 2009 to 27.0% in 2013.

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