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Acacia mearnsii (black wattle) is a commercially important forestry species in South Africa, grown for its timber and bark. Due to its invasiveness, it is also considered be an alien invader species and for this reason the production of a sterile triploid variety would be highly desirable for South African commercial forestry. Previous research on crosses between diploid and tetraploid parent plants to produce triploid progeny has resulted in poor seed set. One possible barrier preventing seed set could be the effect of temperature and relative humidity, within the isolation bags used during cross-pollination operations. For this reason in 2011 diploid polyads were subjected to various temperature and relative humidity combinations, to simulate conditions recorded within the isolation bags being used in the 2010 flowering season in order to see if the conditions were detrimental to polyad viability. The results showed that when polyads were exposed to extreme temperatures (> 30 °C) and low relative humidities (RH's) (10%), polyad viability and pollen tube development, decreased significantly. In contrast the effect of high RH's in combination with low temperatures for long periods appeared to be beneficial to polyad viability and pollen tube growth. The results also indicated that the Australian Centre for International Agricultural Research (ACIAR) agar germination medium was superior to the Brewbaker and Kwack (BK) 30% agar germination medium for determining polyad viability as it resulted in greater number of pollen tubes per polyad, which were healthier in appearance. The Sigma® DAB peroxidase vital stain test overestimated polyad viability and showed no significant differences between the various treatments, highlighting its unreliability as a test. Polyad viability and pollen tube development were compared across three flowering seasons (2009, 2010 and 2011) and similar trends were apparent with some seasonal differences.

The surface sterilisation procedure is of integral importance to any micropropagation technique. This process should do the least amount of plant damage, whilst reducing microbial contamination to an acceptable level. The objective of this research was to investigate alternative sterilisation agents to the dangerous chemical mercuric chloride (HgCl2), and to determine the effect of sterilant exposure time on shoot apex culture of Acacia mearnsii. Explants were cultured on MS medium supplemented with 2.0 mg l–1 BA and monitored for 21 d for signs of contamination and shooting. Household bleach (NaOCl), diluted 1:3 in water, resulted in decontaminated explant levels not significantly different to the 0.2% HgCl2 treatment and resulted in shoot development levels significantly higher than the 0.2% HgCl2 treatment. There was no significant effect of sterilant exposure time on decontaminated explant levels, whilst the shortest exposure time resulted in significantly higher shooting levels than the other two time periods tested. Keywords: Acacia mearnsii, shoot apex culture, sterilisation agent, vegetative propagation

Three assays, namely stomatal length measurements, counts of chloroplast numbers within the stomatal guard cells and flow cytometry, were used to confirm the ploidy of three diploid and three tetraploid Acacia mearnsii lines. The first two methods have previously been successful in identifying ploidy in this species, but they are indirect assessments. Flow cytometry directly quantifies the amount of DNA present in a sample, but has not been previously tested on A. mearnsii. It was decided to test the accuracy of all three methods by using the exact same plant material for each method. Results showed that each method correctly identified the ploidy of the diploid plant material tested as well as two of the three tetraploids tested. All three techniques identified the third tetraploid (C19/48/17) as a diploid, suggesting that its original classification was incorrect. From this study, all three techniques followed the same trend, confirming their accuracy for future research into ploidy identification of A. mearnsii. Flow cytometry has the advantage of providing a quick and efficient direct assessment of DNA in the sample, but is the most expensive. The other two techniques used (stomatal length measurements and counts of chloroplast numbers within the stomatal guard cells) are also accurate but are indirect methods and more time-consuming.

Liver hyperplasia was induced in rats by daily administration of methylclofenapate (25 mg/kg by gavage). An increase in the incidence of colchicine-arrested metaphases was observed with peaks occurring at 40 h (1.3%), 64 h (6.4%) and 84 h (6.8%) after the start of treatment. This response contrasted with the much larger (21.3%) peak in arrested metaphases at 36 h after partial hepatectomy, but was still unexpectedly large in comparison with the S-phase response to methylclofenapate reported in a previous study [13]. Progressive hypertrophic histopathological changes were apparent during the whole course of treatment.

Acacia mearnsii (black wattle) is a commercially important forestry species in South Africa, grown for its timber as well as its bark. It is, however, also considered to be an alien invader of indigenous vegetation and for this reason the production of a sterile variety would be highly desirable for commercial forestry in South Africa. Previous research on crosses between diploid and tetraploid parent plants to produce triploid progeny has resulted in poor seed set. One possible barrier preventing seed set could be the viability of the pollen used in the cross pollination operations. Thus a study was conducted to test the pollen viability. In vitro agar media germination tests (ACIAR and Brewbaker and Kwack media) were optimised on Acacia podalyriifolia pollen and then used together with vital stain tests (Sigma® DAB peroxidase and p-phenylendiamine) to test pollen germination and viability of A. mearnsii pollen. These were then compared to in vivo pollen germination on the stigma, and were conducted on both diploid and tetraploid pollen mixes. Results showed that the vital stain tests gave significantly (p0.05) between the two agar media germination tests and between the two vital stain tests.

The Fiscal Impacts (FI) Model, Version 1.0 was developed under Pacific Northwest Laboratory's Monitored Retrievable Storage (MRS) Program to aid in development of the MRS Reference Site Environmental Document (PNL 5476). It computes estimates of 182 fiscal items for state and local government jurisdictions, using input data from the US Census Bureau's 1981 Survey of Governments and local population forecasts. The model can be adapted for any county or group of counties in the United States.