'Acacia' s.s. comprises approximately 1020 species (i.e. just under one-third of all mimosoid legumes) and is almost entirely restricted to, although widespread, on the Australian continent. We investigated variation in the wood anatomy of 12 species from temperate New South Wales in a study concentrating on four recognised taxonomic sections ('Botrycephalae', 'Juliflorae', 'Phyllodineae' and 'Plurinerves'), to elucidate which characteristics are consistent within the sections, having removed climatic effect as much as possible. The sections had great utility in species identification, whereas none of the wood characters reflected the hypothesised phylogeny of the genus. The main consistent difference among species was in ray width (uniseriate versus 1-3 cells wide). All species had distinct growth rings. The vessels had alternate vestured pitting and simple perforation plates. Fibres were generally thick-walled, and many fibres had a gelatinous inner wall (tension wood fibres) and were inconsistently distributed. Axial parenchyma was mainly paratracheal, ranging from vasicentric to confluent and varied greatly in abundance. Prismatic crystals were usually present in chambered fibres and axial parenchyma strands, and also varied in abundance. The variation in these qualitative characters obscures taxonomic differences, but may allow inferences to be made about environmental adaptation.

This study examined the water relations of sclerophyllous evergreen vegetation (wallum) on coastal sand barriers in eastern Australia. Many wallum species may be groundwater dependent, although the extent of this dependency is largely unknown. Twenty-six perennial tree, shrub and herb species were investigated in three groundwater habitats (ridge, open depression, closed depression). Pre-dawn and midday shoot xylem water potentials (ᴪₓ) were measured monthly between late autumn 2010 and late summer 2011. Pressure-volume curve traits were determined in mid- to late spring 2009, including the osmotic potential at full (π100) and zero (π0) turgor, and bulk modulus of elasticity (ε). Carbon isotope ratios (δ¹³C) were also determined in mid- to late spring 2009, to measure water-use efficiency (WUE). The species displayed a range of physiological strategies in response to water relations, and these strategies overlapped among contrasting growth forms and habitats. Linear relationships between osmotic and elastic adjustment were significant. A strong correlation between δ¹³C and distribution along the hydrological gradient was not apparent. 'Banksia ericifolia' subsp. 'macrantha' (A.S.George) A.S.George, 'Eucalyptus racemosa' Cav. subsp. 'racemosa' and 'Eucalyptus robusta' Sm. displayed little seasonal variation in ᴪₓ and maintained a comparatively high pre-dawn ᴪₓ, and are therefore likely to be phreatophytic. Wetland vegetation in the lowest part of the landscape appeared to tolerate extreme fluctuations in water availability linked to a prevailing climatic pattern of variable and unreliable seasonal rainfall.

Hydroponic experiments were conducted to compare the effects of 'Pythium irregulare' and root pruning on wheat ('Triticum aestivum' cv. Janz) transpiration, water-use efficiency (WUE) and plant growth in the presence and absence of polyethylene glycol-induced drought (PEG). 'Pythium', PEG and root pruning reduced transpiration to a similar extent, but the mechanism that affects transpiration differed between the treatments. Reduced hydraulic conductivity of roots caused by disease in the 'Pythium' treatment and reduced size of the root system in the root pruning treatment were responsible for decreased transpiration while reduction of stomatal conductance was the main cause for reduced transpiration in the PEG treatment. 'Pythium' reduced shoot dry weight and increased root/shoot ratio but had no effect on whole-plant or instantaneous WUE. There was a small additive effect of 'Pythium' on whole-plant transpiration of plants exposed to PEG-induced drought, but there was no evidence of an interaction between 'Pythium' and PEG-induced drought on WUE or growth. This suggests that moderate root damage by pathogens is likely to have only a modest effect on the water relations of wheat plants.

The hypothesis that root rot caused by Pythium irregulare reduces the water use efficiency of wheat was tested in a system which simulated field conditions with late season water stress. Inoculation with Pythium significantly reduced transpiration during vegetative growth, so that plants entered post-anthesis drought with more available water. Although weekly transpiration rates were higher in inoculated plants than controls during the later stages of drought, infected plants were unable to make use of all of the extra water. There were no significant effects of inoculation on shoot biomass or grain yield, while total transpiration was reduced by 14%. Infected plants therefore had significantly higher integrated water use efficiency (grain yield relative to transpiration) than controls. Infected plants were significantly more stressed than controls during the drought, despite higher soil moisture, and showed reduced ability to use stomatal conductance to regulate leaf water potential. Pythium infection caused adverse changes to plant water use and water relations, but these did not translate into reductions in growth or yield. This, and the unexpected increase in water use efficiency, highlights the need to consider interactions with other environmental stresses when making assumptions about the effects of root diseases on crop productivity.

A pot experiment investigated the effects of root diseases (Pythium and Rhizoctonia) under drought conditions at either tillering or anthesis stages on the water-use efficiency (WUE), water relations, and yield components of wheat cultivars Janz and Mulgara. The pathogens reduced transpiration in Janz during drought at tillering and in both cultivars during the period of recovery after drought at anthesis. However, the pathogens did not affect WUE. WUE did not differ between well-watered plants and those droughted at tillering but it was reduced by 80% by drought at anthesis. Un-infected plants of cultivar Janz subjected to drought at tillering had a higher total water potential (Ψ_w) and osmotic potential (Ψ_s) than diseased plants. However, Ψ_s of un-inoculated plants that were droughted at anthesis was lower than diseased plants in the period following anthesis. Yield components were significantly higher in well-watered than droughted plants and higher in cv. Mulgara than cv. Janz. The pathogens affected transpiration during tillering, but not at later stages, when roots developed beyond the inoculation point. Although the pathogens caused damage to the roots, the effects on water relations parameters were minor. This suggests that wheat can tolerate moderate levels of these root diseases under drought.

Water availability influences regional tree distributions in rainforests, often by affecting survival of seedlings. The occurrence of 'dry rainforest' species in subhumid climates has been attributed to the evolution of drought-resistant species from their mesic rainforest congeners. Many genera are found in both dry and mesic rainforest of Australia but the extent to which this is due to differential drought resistance has not been confirmed experimentally. We compared drought survival within three congeneric pairs of dry and mesic rainforest taxa in a glasshouse dry-down experiment. Soil type could also play a role, with dry rainforests mostly occurring on fine-textured soils such as loams, which have a high available water-holding capacity, compensating for lower rainfall. Hence, we grew plants in loam or sand soil. In all pairs, the dry rainforest taxon was better able to survive drought, providing support for the climate-induced evolution of a dry rainforest flora and further confirming that drought resistance of seedlings can shape tree species distributions at regional scales. Two of three pairs had higher seedling survival on basalt-derived loam soil, suggesting that such soils may aid seedling persistence during drought. Over evolutionary time, this may have resulted in the high fidelity of dry rainforest for these soils.

This book is a fascinating and compelling account of over 30 years of distinguished service of the Royal Air Force Armoured Cars from Iraq, Jordan, Palestine and Aden, to North Africa.

Formed in the early 1920s as a key component of the RAF Scheme of Air Control, they supported the League of Nations Mandates in Palestine and Iraq following the Great War. Air control, based on the use of aircraft, armoured cars and locally-recruited levies, was an effective and efficient means of policing and controlling the tribes and townspeople of these territories.

The work of the RAF Armoured Car Companies, which became Squadrons of the RAF Regiment in 1946, was many and varied; patrolling the mountains and deserts, protecting RAF airfields and convoys, "showing the flag", escorting VIPs and coordinating air and ground operations. They were called in on numerous occasions to suppress troubles from ethnic and tribal groups, and to contain rebellions and invasions while working in close cooperation with the flying squadrons of the RAF.

One of their greatest contributions was made early in the Second World War when Nos 1 and 2 Companies both played a major role in preventing Iraq and Syria falling into the hands of the Axis forces.

This book draws on RAF official records at the National Archives of the United Kingdom, the personal diaries, letters, and reminiscences held at the Imperial War Museum, RAF Museum Hendon, and RAF Regiment Museum and by the RAF Armoured Cars Association, as well as the author's interviews with the officers and airmen who served in the RAF Armoured Cars.

The author presents the story not only in the political, strategic and tactical context of operations, but also gives the view from the turret and driver's seat of the car commanders, gunners, wireless operators and fitters.

Calcium oxalate (CaOx) crystals are a common natural feature of many plant families, including the Leguminosae. The functional role of crystals and the mechanisms that underlie their deposition remain largely unresolved. In several species, the seasonal deposition of crystals has been observed. To gain insight into the effects of rainfall on crystal formation, the morphology, distribution and accumulation of calcium oxalate crystals in phyllodes of the leguminous 'Acacia' sect. 'Juliflorae' (Benth.) C. Moore & Betche from four climate zones along an aridity gradient, was investigated. The shapes of crystals, which include rare Rosanoffian morphologies, were constant between species from different climate zones, implying that morphology was not affected by rainfall. The distribution and accumulation of CaOx crystals, however, did appear to be climate-related. Distribution was primarily governed by vein density, an architectural trait which has evolved in higher plants in response to increasing aridity. Furthermore, crystals were more abundant in acacias from low rainfall areas, and in phyllodes containing high concentrations of calcium, suggesting that both aridity and soil calcium levels play important roles in the precipitation of CaOx. As crystal formation appears to be calcium-induced, we propose that CaOx crystals in Acacia most likely function in bulk calcium regulation.

Background and Objective: Seaweeds and seaweed products have been applied in vegetable production systems for many years. Seaweeds and their extracts or by-products may have beneficial effects on vegetable production through increased growth. Possible mechanisms include the nutrient concentration of the seaweed product, the presence of organic compounds such as plant growth regulators (PGR), or through effects on soil processes. Materials and Methods: The effect of application rates and whether mineral nutrients alone can account for plant growth responses, was assessed by using two commercial seaweed products (Maxicrop® and Seasol®) applied at four rates (0, 1, 2, 4 ×recommended rate) as well as ashed product and an equivalent mineral fertilizer treatment with the same nutrient content as the recommended rates for each seaweed product. Results: The results show that both Maxicrop and Seasol can significantly increase crop performance. Maxicrop increased shoot biomass, root biomass and leaf chlorophyll content above that of the mineral treatments by 66, 47 and 9%, respectively, while Seasol increased root biomass only (by 50%). By ashing the seaweed product or preparing a mineral-only nutrient solution, we have confirmed that seaweed products can improve plant growth beyond that of mineral nutrients alone. However, seaweed fertilizer products with very low nutrient analysis may be unlikely to improve plant growth without supplementary nutrient additions from other sources. Where the nutrient content is adequate, growth may be greater than equivalent mineral nutrient applications. Conclusion: These pot trials demonstrate the potential value of some seaweed fertiliser products for nursery production and other containerised plant systems. Further research is required to clarify the role of various plant growth regulators, biostimulants and soil conditioning compounds.

The present study examined the water relations of wallum dry sclerophyll woodland on the lower north coast of New South Wales (NSW). Wallum is the regionally distinct vegetation of Quaternary dunefields and beach ridge plains along the eastern coast of Australia. Wallum sand masses contain large aquifers, and previous studies have suggested that many of the plant species may be groundwater dependent. However, the extent of this dependency is largely unknown, despite an increasing reliance on the aquifers for groundwater extraction. Fifteen species from five growth-form categories and seven plant families were investigated. The pre-dawn and midday xylem water potential (Ψₓ) of all species was monitored over a 20-month period from December 2007 to July 2009. Pressure-volume curve traits were determined for each species in late autumn 2008, including the osmotic potential at full (π₁₀₀) and zero (π₀) turgor, and bulk modulus of elasticity (ε). Carbon isotope ratios (δ¹³C) were determined in mid-autumn 2008 to measure water use efficiency (WUE). Comparative differences in water relations could be loosely related to growth forms. A tree (Eucalyptus 'racemosa' subsp. 'racemosa') and most large shrubs had low midday Ψₓ, π₁₀₀ and π₀, and high ε and WUE; whereas the majority of small and medium shrubs had high midday Ψₓ, π₁₀₀ and π₀, and low ε and WUE.However, some species of similar growth form displayed contrasting behaviour in their water relations (e.g. the herbs 'Caustis recurvata' var. 'recurvata' and 'Hypolaena fastigiata'), and such differences require further investigation. The results suggest that 'E. racemosa' subsp. 'racemosa' is likely to be groundwater dependent, and large shrubs such as 'Banksia aemula' may also utilise groundwater. Both species are widespread in wallum, and therefore have the potential to play a key role in monitoring ecosystem health where aquifers are subject to groundwater extraction.