Water and thermal regimes for field pea in Australia and their implications for breeding.

There is a large gap between the refined approaches to characterise genotypes and the common use of location and season as a coarse surrogate for environmental characterisation of breeding trials. As a framework for breeding, the aim of this paper is quantifying the spatial and temporal patterns of thermal and water stress for field pea in Australia. We compiled a dataset for yield of the cv. Kaspa measured in 185 environments, and investigated the associations between yield and seasonal patterns of actual temperature and modelled water stress. Correlations between yield and temperature indicated two distinct stages. In the first stage, during crop establishment and canopy expansion before flowering, yield was positively associated with minimum temperature. Mean minimum temperature below similar to 7 degrees C suggests that crops were under suboptimal temperature for both canopy expansion and radiation-use efficiency during a significant part of this early growth period. In the second stage, during critical reproductive phases, grain yield was negatively associated with maximum temperature over 25 degrees C. Correlations between yield and modelled water supply/demand ratio showed a consistent pattern with three phases: no correlation at early stages of the growth cycle, a progressive increase in the association that peaked as the crop approached the flowering window, and a progressive decline at later reproductive stages. Using long-term weather records (1957-2010) and modelled water stress for 104 locations, we identified three major patterns of water deficit nation wide. Environment type 1 (ET1) represents the most favourable condition, with no stress during most of the pre-flowering phase and gradual development of mild stress after flowering. Type 2 is characterised by increasing water deficit between 400 degree-days before flowering and 200 degree-days after flowering and rainfall that relieves stress late in the season. Type 3 represents the more stressful condition with increasing water deficit between 400 degree-days before flowering and maturity. Across Australia, the frequency of occurrence was 24% for ET1, 32% for ET2 and 43% for ET3, highlighting the dominance of the most stressful condition. Actual yield averaged 2.2 t/ha for ET1, 1.9 t/ha for ET2 and 1.4 t/ha for ET3, and the frequency of each pattern varied substantially among locations. Shifting from a nominal (i.e. location and season) to a quantitative (i.e. stress type) characterisation of environments could help improving breeding efficiency of field pea in Australia.

Fabrication and characterization of plasma polymer thin films from monoterpene alcohols for applications in organic electronics and biotechnology

After more than twenty years of basic and applied research, the use of nanotechnology in the design and manufacture of nanoscale materials is rapidly increasing, particularly in commercial applications that span from electronics across renewable energy areas, and biomedical devices. Novel polymers are attracting significant attention for they promise to provide a low−cost high−performance alternative to existing materials. Furthermore, these polymers have the potential to overcome limitations imposed by currently available materials thus enabling the development of new technologies and applications that are currently beyond our reach. This work focuses on the development of a range of new low−cost environmentally−friendly polymer materials for applications in areas of organic (flexible) electronics, optics, and biomaterials. The choice of the monomer reflects the environmentally−conscious focus of this project. Terpinen−4−ol is a major constituent of Australian grown Melaleuca alternifolia (tea tree) oil, attributed with the oil's antimicrobial and anti−inflammatory properties. Plasma polymerisation was chosen as a deposition technique for it requires minimal use of harmful chemicals and produces no hazardous by−products. Polymer thin films were fabricated under varied process conditions to attain materials with distinct physico−chemical, optoelectrical, biological and degradation characteristics. The resultant materials, named polyterpenol, were extensively characterised using a number of well−accepted and novel techniques, and their fundamental properties were defined. Polyterpenol films were demonstrated to be hydrocarbon rich, with variable content of oxygen moieties, primarily in the form of hydroxyl and carboxyl functionalities. The level of preservation of original monomer functionality was shown to be strongly dependent on the deposition energy, with higher applied power increasing the molecular fragmentation and substrate temperature. Polyterpenol water contact angle contact angle increased from 62.7° for the 10 W samples to 76.3° for the films deposited at 100 W. Polymers were determined to resist solubilisation by water, due to the extensive intermolecular and intramolecular hydrogen bonds present, and other solvents commonly employed in electronics and biomedical processing. Independent of deposition power, the surface topography of the polymers was shown to be smooth (Rq <0.5 nm), uniform and defect free. Hardness of polyterpenol coatings increased from 0.33 GPa for 10 W to 0.51 GPa for 100 W (at 500 μN load). Coatings deposited at higher input RF powers showed less mechanical deformation during nanoscratch testing, with no considerable damage, cracking or delamination observed. Independent of the substrate, the quality of film adhesion improved with RF power, suggesting these coatings are likely to be more stable and less susceptible to wear. Independent of fabrication conditions, polyterpenol thin films were optically transparent, with refractive index approximating that of glass. Refractive index increased slightly with deposition power, from 1.54 (10 W) to 1.56 (100 W) at 500 nm. The optical band gap values declined with increasing power, from 2.95 eV to 2.64 eV, placing the material within the range for semiconductors. Introduction of iodine impurity reduced the band gap of polyterpenol, from 2.8 eV to 1.64 eV, by extending the density of states more into the visible region of the electromagnetic spectrum. Doping decreased the transparency and increased the refractive index from 1.54 to 1.70 (at 500 nm). At optical frequencies, the real part of permittivity (k) was determined to be between 2.34 and 2.65, indicating a potential low-k material. These permittivity values were confirmed at microwave frequencies, where permittivity increased with input RF energy – from 2.32 to 2.53 (at 10 GHz ) and from 2.65 to 2.83 (at 20 GHz). At low frequencies, the dielectric constant was determined from current−voltage characteristics of Al−polyterpenol−Al devices. At frequencies below 100 kHz, the dielectric constant varied with RF power, from 3.86 to 4.42 at 1 kHz. For all samples, the resistivity was in order of 10⁸−10⁹ _m (at 6 V), confirming the insulating nature of polyterpenol material. In situ iodine doping was demonstrated to increase the conductivity of polyterpenol, from 5.05 × 10⁻⁸ S/cm to 1.20 × 10⁻⁶ S/cm (at 20 V). Exposed to ambient conditions over extended period of time, polyterpenol thin films were demonstrated to be optically, physically and chemically stable. The bulk of ageing occurred within first 150 h after deposition and was attributed to oxidation and volumetric relaxation. Thermal ageing studies indicated thermal stability increased for the films manufactured at higher RF powers, with degradation onset temperature associated with weight loss shifting from 150 ºC to 205 ºC for 10 W and 100 W polyterpenol, respectively. Annealing the films to 405 °C resulted in full dissociation of the polymer, with minimal residue. Given the outcomes of the fundamental characterisation, a number of potential applications for polyterpenol have been identified. Flexibility, tunable permittivity and loss tangent properties of polyterpenol suggest the material can be used as an insulating layer in plastic electronics. Implementation of polyterpenol as a surface modification of the gate insulator in pentacene-based Field Effect Transistor resulted in significant improvements, shifting the threshold voltage from + 20 V to –3 V, enhancing the effective mobility from 0.012 to 0.021 cm²/Vs, and improving the switching property of the device from 10⁷ to 10⁴. Polyterpenol was demonstrated to have a hole transport electron blocking property, with potential applications in many organic devices, such as organic light emitting diodes. Encapsulation of biomedical devices is also proposed, given that under favourable conditions, the original chemical and biological functionality of terpinen−4−ol molecule can be preserved. Films deposited at low RF power were shown to successfully prevent adhesion and retention of several important human pathogens, including P. aeruginosa, S. aureus, and S. epidermidis, whereas films deposited at higher RF power promoted bacterial cell adhesion and biofilm formation. Preliminary investigations into in vitro biocompatibility of polyterpenol demonstrated the coating to be non−toxic for several types of eukaryotic cells, including Balb/c mice macrophage and human monocyte type (HTP−1 non-adherent) cells. Applied to magnesium substrates, polyterpenol encapsulating layer significantly slowed down in vitro biodegradation of the metal, thus increasing the viability and growth of HTP−1 cells. Recently, applied to varied nanostructured titanium surfaces, polyterpenol thin films successfully reduced attachment, growth, and viability of P. aeruginosa and S. aureus.

Impact of partial removal of the invasive macrophyte Lagarosiphon major (hydrocharitaceae) on invertebrates and fish

Invasive macrophyte species are a threat to native biodiversity and often grow to nuisance levels, therefore, making control options necessary. Macrophyte control can have pronounced impacts on littoral fish by reducing habitat heterogeneity and the loss of profitable (high density of invertebrates) foraging areas. Yet, there is little known about the impacts of macrophyte removal on invertebrates themselves. We conducted a macrophyte removal experiment, that is the cutting of channels into dense macrophyte beds, to investigate the impact of mechanical macrophyte control on invertebrate and fish communities in a littoral zone dominated by the invasive macrophyte Lagarosiphon major. The effect of macrophyte removal had only a temporary effect on macrophyte areal cover (4 months). Nevertheless, the treatment increased light penetration significantly. However, we could not detect any difference in epiphyton biomass. Invertebrate biomass increased in macrophyte stands 4 months after treatment and there was a shift in the invertebrate community composition. Mechanical control had no effect on invertebrate biodiversity. The higher invertebrate biomass did not translate into a higher fish density in the treated areas. The results of this study indicated that partial mechanical removal is a suitable option to control unwanted macrophyte stands.

Rotary veneering of plantation-grown spotted gum (Corymbia citriodora subsp. variegata) and Dunn's white gum (Eucalyptus dunnii)

This report evaluates the wood and veneer properties of plantation-grown spotted gum (Corymbia citriodora subsp. variegata, or CCV) and Dunn's white gum (Eucalyptus dunnii), grown at different stockings, in thinning trials near Ellangowan in north-east New South Wales (mean annual rainfall 1050 mm) and Kingaroy in south-east Queensland (mean annual rainfall 873 mm). Thinning trials were established at age seven years. Both species showed a significant increase in stem diameter growth of the dominant trees in response to thinning. At age 10 years, trees from the unthinned (950–1270 stems ha-1) and 300 stems ha-1 treatments were selected for veneering. Five dominant trees were felled from each combination of species x sites x thinning treatment. Diameter at breast height over bark of the selected trees ranged from 20 cm to 27 cm at Ellangowan, and 19 cm to 26 cm at Kingaroy. From each tree, 1.5 m long billets were removed at two positions: a butt billet from 0.3–1.8 m above ground and a top billet from approximately 5.5–7.0 m. Log end splitting was assessed 24 hours after harvesting and again after steaming, approximately four days after harvesting. Disks from just above both billets were collected for assessment of wood properties. Billets were peeled on a spindleless veneer lathe to produce a full veneer ribbon with a target green thickness of 2.8 to 3.0 mm. The 1.55 m wide (tangential dimension) veneer sheets were dried and graded according to AS/NZ Standard 2269:2008, which describes four veneer grades. Veneer samples taken along the length of the veneer ribbon, at regular intervals of 1.55 m, were tested for stiffness, shrinkage and density. Veneer length measurements were used to calculate the radial distance of each sample from the central axis of the billet. Overall veneer gross recoveries ranged from 50% to 70%. They were significantly lower at the Kingaroy site, for both species. The veneer recoveries achieved were 2–3 times higher than typical green off saw recoveries from small plantation hardwood logs of similar diameter. Most of the veneer recovered was classified as D-grade. CCV trees from the Ellangowan site yielded up to 38% of the better C-grade and higher grade veneers. The main limiting factors that prevented veneer from meeting higher grades were the presence of kino defects and encased knots. Splits in E. dunnii veneer also contributed to reduced grade quality. Log end splits were higher for E. dunnii than for CCV, and logs from Ellangowan exhibited more severe splitting. Split index was generally higher for top than for butt billets. Split index was strongly correlated with the average veneer grade from corresponding billets. The Ellangowan site, where rainfall was higher and trees grew faster, yielded significantly denser and stiffer veneers than did the drier sites near Kingaroy, where tree growth was slower. The difference was more pronounced for E. dunnii than for CCV. Differences in measured wood properties between thinned and unthinned treatments were generally small and not significant. On average, 10% of billet volume was lost during the peeling rounding-up process. Much of the wood laid down following thinning was removed during rounding-up, meaning the effect of thinning on veneer properties could not be effectively assessed. CCV was confirmed as having high veneer density and very good veneer stiffness, exceeding 15 GPa, making it very suitable for structural products. E. dunnii also demonstrated good potential as a useful structural plywood resource, achieving stiffness above 10 GPa. Veneer stiffness and density in CCV increased from pith to bark at both sites, while for E. dunnii there was a radial increase in these properties at the Ellangowan site only. At the drier Kingaroy site, veneer stiffness and density declined from mid-radius to the log periphery. This may be associated with prolonged drought from 2005 to 2009, corresponding to the later years of tree growth at the Kingaroy site. CCV appeared to be less sensitive to drought conditions. Standing tree acoustic velocity, determined by the Fakopp time-of-flight method, provided a reliable prediction of average veneer stiffness for both species (R2=0.78 for CCV and R2=0.90 for E. dunnii) suggesting that the Fakopp method may be a useful indicator of tree and stand quality, in terms of veneer stiffness in standing trees.

Ecological restoration of forests in Fennoscandia : Defining reference stand structures and immediate effects of restoration.

The first aim of this thesis was to explore the structural characteristics of near-natural forests and to quantify how human utilization has changed them. For this, we examined the stand characteristics in Norway spruce Picea abies (L.) Karst-dominated old-growth stands in northwestern Russia and in old Scots pine Pinus sylvestris L.-dominated stands in three regions from southern Finland to northwestern Russia. In the second study, we also compared stands with different degrees of human impact, from near-natural stands and stands selectively cut in the past to managed stands. Secondly, we used an experimental approach to study the short-term effects of different restorative treatments on forest structure and regeneration in managed Picea abies stands in southern Finland. Restorative treatments consisted of a partial cut combined with three levels of coarse woody debris retention, and a fire/no-fire treatment. In addition, we examined burned and unburned reference stands without cutting treatments. Results from near-natural Picea abies forests emphasize the dynamic character of old-growth forests, the variety of late-successional forest structures, and the fact that extended time periods are needed to attain certain late-successional stages with specific structural and habitat attributes, such as large-diameter deciduous trees and a variety of deadwood. The results from old Pinus sylvestris-dominated forests showed that human impact in the form of forest utilization and fire exclusion has strongly modified and reduced the structural complexity of stands. Consequently, small protected forest fragments in Finland may not serve as valid natural reference areas for forest restoration. However, results from the restoration experiment showed that early-successional natural stand characteristics can be restored to structurally impoverished managed Picea abies stands, despite a significant portion of wood volume being harvested. A variety of restoration methods is needed, due to differences in the condition of the forest when restoration is initiated and the variety of successional stages of forest structures after anthropogenic and natural disturbances. Keywords: dead wood, disturbance dynamic, fire, near-natural stand, rehabilitation, succession

Soil hydrological properties and conditions, site preparation, and the long-term performance of planted Scots pine (Pinus sylvestris L.) on upland forest sites in Finnish Lapland

Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) forests dominate in Finnish Lapland. The need to study the effect of both soil factors and site preparation on the performance of planted Scots pine has increased due to the problems encountered in reforestation, especially on mesic and moist, formerly spruce-dominated sites. The present thesis examines soil hydrological properties and conditions, and effect of site preparation on them on 10 pine- and 10 spruce-dominated upland forest sites. Finally, the effects of both the site preparation and reforestation methods, and soil hydrology on the long-term performance of planted Scots pine are summarized. The results showed that pine and spruce sites differ significantly in their soil physical properties. Under field capacity or wetter soil moisture conditions, planted pines presumably suffer from excessive soil water and poor soil aeration on most of the originally spruce sites, but not on the pine sites. The results also suggested that site preparation affects the soil-water regime and thus prerequisites for forest growth over two decades after site preparation. High variation in the survival and mean height of planted pine was found. The study suggested that on spruce sites, pine survival is the lowest on sites that dry out slowly after rainfall events, and that height growth is the fastest on soils that reach favourable aeration conditions for root growth soon after saturation, and/or where the average air-filled porosity near field capacity is large enough for good root growth. Survival, but not mean height can be enhanced by employing intensive site preparation methods on spruce sites. On coarser-textured pine sites, site preparation methods don t affect survival, but methods affecting soil fertility, such as prescribed burning and ploughing, seem to enhance the height growth of planted Scots pines over several decades. The use of soil water content in situ as the sole criterion for sites suitable for pine reforestation was tested and found to be a relatively uncertain parameter. The thesis identified new potential soil variables, which should be tested using other data in the future.

Comparative analysis of Tritrichomonas foetus (Riedmuller, 1928) cat genotype, T. foetus (Riedmuller, 1928) cattle genotype and Tritrichomonas suis (Davaine, 1875) at 10 DNA loci

The parasitic protists in the genus Tritrichomonas cause significant disease in domestic cattle and cats. To assess the genetic diversity of feline and bovine isolates of Tritrichomonas foetus (Riedmuller, 1928) Wenrich and Emmerson, 1933, we used 10 different genetic regions, namely the protein coding genes of cysteine proteases 1,2 and 4-9 (CP1, 2, 4-9) involved in the pathogenesis of the disease caused by the parasite. The cytosolic malate dehydrogenase 1 (MDH1) and internal transcribed spacer region 2 of the rDNA unit (ITS2) were included as additional markers. The gene sequences were compared with those of Tritrichomonas suis (Davaine. 1875) Morgan and Hawkins, 1948 and Tritrichomonas mobilensis Culberson et al., 1986. The study revealed 100% identity for all 10 genes among all feline isolates (=T. foetus cat genotype), 100% identity among all bovine isolates (=T. foetus cattle genotype) and a genetic distinctness of 1% between the cat and cattle genotypes of T. foetus. The cattle genotype of T. foetus was 100% identical to T. suis at nine loci (CP1, 2,4-8, ITS2, MDH1). At CP9, three out of four T. suis isolates were identical to the T. foetus cattle genotype, while the T. suis isolate SUI-H3B sequence contained a single unique nucleotide substitution. Tritrichomonas mobilensis was 0.4% and 0.7% distinct from the cat and cattle genotypes of T. foetus, respectively. The genetic differences resulted in amino acid changes in the CP genes, most pronouncedly in CP2, potentially providing a platform for elucidation of genotype-specific host-pathogen interactions of T. foetus. On the basis of this data we judge T. suis and T. foetus to be subjective synonyms. For the first time, on objective nomenclatural grounds, the authority of T. suis is given to Davaine, 1875, rather than the commonly cited Gruby and Delafond, 1843. To maintain prevailing usage of T. foetus, we are suppressing the senior synomym T. suis Davaine, 1875 according to Article 23.9, because it has never been used as a valid name after 1899 and T. foetus is widely discussed as the cause of bovine trichomonosis. Thus bovine, feline and porcine isolates should all be given the name T. foetus. This promotes the stability of T. foetus for the veterinary and economically significant venereal parasite causing bovine trichomonosis. (C) 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Impact of low temperature storage on active and storage forms of folate in choy sum (Brassica rapa subsp parachinensis)

Choy sum (Brassica rapa subsp. parachinensis) is a dark green leafy vegetable that contains high folate (vitamin B9) levels comparable to spinach. Folate is essential for the maintenance of human health and is obtained solely through dietary means. Analysis of the edible portion of choy sum by both microbiological assay and LC-MS/MS indicated that total folate activity remained significantly unchanged over 3 weeks storage at 4 degrees C. Inedible fractions consisted primarily of outer leaves, which showed signs of rotting after 14d, and a combination of rotting and yellowing after 21 d, contributing to 20% and 40% of product removal, respectively. Following deconjugation of the folate present in choy sum to monoglutamate and diglutamate derivatives, the principal forms (vitamers) of folate detected in choy sum were 5-methyltetrahydrofolate and 5-formyl tetrahydrofolate, followed by tetrahydrofolate (THF), 5,10-methenyl-THF, and 10-formyl folic acid. During storage, a significant decline in 5-formyl-THF was observed, with a slight but not significant increase in the combined 5-methyl-THF derivatives. The decline in 5-formyl-THF in relation to the other folate vitamers present may indicate that 5-formyl-THF is being utilised as a folate storage reserve, being interconverted to more metabolically active forms of folate, such as 5-methyl-THF. Although folate vitamer profile changed over the storage period, total folate activity did not significantly change. From a human nutritional perspective this is important, as while particular folate vitamers (e.g. 5-methyl-THF) are necessary for maintaining vital aspects of plant metabolism, it is less important to the human diet, as humans can absorb and interconvert multiple forms of folate. The current trial indicates that it is possible to store choy sum for up to 3 weeks at 4 degrees C without significantly affecting total folate concentration of the edible portion. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Structural analyses of (1->3),(1->4)-β-D-glucan of oats and barley

The structures of (1→3),(1→4)-β-D-glucans of oat bran, whole-grain oats and barley and processed foods were analysed. Various methods of hydrolysis of β-glucan, the content of insoluble fibre of whole grains of oats and barley and the solution behaviour of oat and barley β-glucans were studied. The isolated soluble β-glucans of oat bran and whole-grain oats and barley were hydrolysed with lichenase, an enzyme specific for (1→3),(1→4)-β-D-β-glucans. The amounts of oligosaccharides produced from bran were analysed with capillary electrophoresis and those from whole-grains with high-performance anion-exchange chromatography with pulse-amperometric detection. The main products were 3-O-β-cellobiosyl-D-glucose and 3-O-β-cellotriosyl-D-glucose, the oligosaccharides which have a degree of polymerisation denoted by DP3 and DP4. Small differences were detected between soluble and insoluble β-glucans and also between β-glucans of oats and barley. These differences can only be seen in the DP3:DP4 ratio which was higher for barley than for oat and also higher for insoluble than for soluble β-glucan. A greater proportion of barley β-glucan remained insoluble than of oat β-glucan. The molar masses of soluble β-glucans of oats and barley were the same as were those of insoluble β-glucans of oats and barley. To analyse the effects of cooking, baking, fermentation and drying, β-glucan was isolated from porridge, bread and fermentate and also from their starting materials. More β-glucan was released after cooking and less after baking. Drying decreased the extractability for bread and fermentate but increased it for porridge. Different hydrolysis methods of β-glucan were compared. Acid hydrolysis and the modified AOAC method gave similar results. The results of hydrolysis with lichenase gave higher recoveries than the other two. The combination of lichenase hydrolysis and high-performance anion-exchange chromatography with pulse-amperometric detection was found best for the analysis of β-glucan content. The content of insoluble fibre was higher for barley than for oats and the amount of β-glucan in the insoluble fibre fraction was higher for oats than for barley. The flow properties of both water and aqueous cuoxam solutions of oat and barley β-glucans were studied. Shear thinning was stronger for the water solutions of oat β-glucan than for barley β-glucan. In aqueous cuoxam shear thinning was not observed at the same concentration as in water but only with high concentration solutions. Then the viscosity of barley β-glucan was slightly higher than that of oat β-glucan. The oscillatory measurements showed that the crossover point of the G´ and G´´ curves was much lower for barley β-glucan than for oat β-glucan indicating a higher tendency towards solid-like behaviour for barley β-glucan than for oat β-glucan.

Biosynthesis of Long-Chain Alcohols by Developing and Regenerating Rat Sciatic Nerve

Cell-free preparations of rat sciatic nerve were found to catalyze the reduction of fatty acid to alcohol in the presence of NADPH as reducing cofactor. The reductase was membrane-bound and associated primarily with the microsomal fraction. When fatty acid was the substrate, ATP, coenzyme A (CoA), and Mg2+ were required, indicating the formation of acyl CoA prior to reduction. When acyl CoA was used as substrate, the presence of albumin was required to inhibit acyl CoA hydro-lase activity. Fatty acid reductase activity was highest with palmitic and stearic acids, and somewhat lower with lauric and myristic acids. It was inhibited by sulfhydryl reagents, indicating the participation of thiol groups in the reduction. Only traces of long-chain aldehyde could be detected or trapped as semicarbazone. Fatty acid reductase activity in rat sciatic nerve was highest between the second and tenth days after birth and decreased substantially thereafter. Microsomal preparations of sciatic nerve from 10-day-old rats exhibited about four times higher fatty acid reductase activity than brain or spinal cord microsomes from the same animals. Wallerian degeneration and regeneration of adult rat sciatic nerve resulted in enhanced fatty acid reductase activity, which reached a maximum at about 12 days after crush injury.

Pollination methods, stigma receptivity and pollen tube growth in Eucalyptus argophloia

Eucalyptus argophloia Blakely (Western white gum) has shown potential as a commercial forestry timber species in marginal environments of north-eastern Australia. We measured early pollination success in Eucalyptus argophloia to compare pollination methods, determine the timing of stigma receptivity and compare fresh and stored pollen. Early pollination success was measured by counting pollen tubes in the style of E. argophloia 12 days after pollination. We compared the early pollination success of 1) Artificially Induced Protogyny (AIP), one-stop and three-stop methods of pollination; 2) flowers pollinated at 2 day intervals between 2 days before and 6 days after anthesis and 3) fresh pollen and pollen that had been stored for 9 months. Our results show significantly more pollen tubes from unpollinated AIP and AIP treatments than either the one-stop pollination or three-stop pollination treatments. This indicates that self-pollination occurs in the unpollinated AIP treatment. There was very little pollen tube growth in the one-stop method indicating that the three-stop method is the most suitable for this species. Stigma receptivity in E. argophloia commenced six days after anthesis and no pollen tube growth was observed prior to this. Fresh pollen resulted in pollen tube growth in the style whereas the stored pollen resulted in a total absence of pollen tube growth. We recommend that breeding programs incorporating E. argophloia as a female parent use the three-stop pollination method, and controlled pollination be carried out at least six days after anthesis using fresh pollen.

Mannans as film formers and emulsion stabilizers

Mannans are abundant plant polysaccharides found in the endosperm of certain leguminous seeds (guar gum galactomannan, GG; locust bean gum galactomannan, LBG), in the tuber of the konjac plant (konjac glucomannan, KGM), and in softwoods (galactoglucomannan, GGM). This study focused on the effects of the chemical structure of mannans on their film-forming and emulsion-stabilizing properties. Special focus was on spruce GGM, which is an interesting new product from forest biorefineries. A plasticizer was needed for the formation of films from mannans other than KGM and the optimal proportion was 40% (w/w of polymers) glycerol or sorbitol. Galactomannans with lower galactose content (LBG, modified GG) produced films with higher elongation at break and tensile strength. The mechanical properties of GG-based films were improved by decreasing the degree of polymerization of the polysaccharide with moderate mannanase treatments. The improvement of mechanical properties of GGM-based films was sought by blending GGM with each of poly(vinyl alcohol) (PVOH), corn arabinoxylan (cAX), and KGM. Adding other polymers increased the elongation at break of GGM blend films. The tensile strength of films increased with increasing amounts of PVOH and KGM, but the effect of cAX was the opposite. Dynamic mechanical analysis showed two separate loss modulus peaks for blends of GGM and PVOH, but a single peak for all other films. Optical and scanning electron microscopy confirmed good miscibility of GGM with cAX and KGM. In contrast, films blended from GGM and PVOH showed phase separation. GGM and KGM were mixed with cellulose nanowhiskers (CNW) to form composite films. Addition of CNW to KGM-based films induced the formation of fiberlike structures with lengths of several millimeters. In GGM-based films, rodlike structures with lengths of tens of micrometers were formed. Interestingly, the notable differences in the film structure did not appear to be related to the mechanical and thermal properties of the films. Permeability properties of GGM-based films were compared to those of films from commercial mannans KGM, GG, and LBG. GGM-based films had the lowest water vapor permeability when compared to films from other mannans. The oxygen permeability of GGM films was of the same magnitude as that of commercial polyethylene / ethylene vinyl alcohol / polyethylene laminate film. The aroma permeability of GGM films was low. All films were transparent in the visible region, but GGM films blocked the light transmission in the ultraviolet region of the spectra. The stabilizing effect of GGM on a model beverage emulsion system was studied and compared to that of GG, LBG, KGM, and cAX. In addition, GG was enzymatically modified in order to examine the effect of the degree of polymerization and the degree of substitution of galactomannans on emulsion stability. Use of GGM increased the turbidity of emulsions both immediately after preparation and after storage of up to 14 days at room temperature. GGM emulsions had higher turbidity than the emulsions containing other mannans. Increasing the storage temperature to +45 ºC led to rapid emulsion breakdown, but a decrease in storage temperature increased emulsion stability after 14 days. A low degree of polymerization and a high degree of substitution of the modified galactomannans were associated with a decrease in emulsion turbidity.

Symptom development proceeds at different rates in susceptible and partially resistant cereal seedlings infected with Fusarium pseudograminearum

Variation in the reaction of cereal cultivars to crown rot caused by Fusarium spp., in particular Fusarium pseudograminearum, was identified over 50 yrs ago, however the parameters and pathways of infection by F. pseudograminearum remain poorly understood. Seedlings of wheat, barley and oat genotypes that differ in susceptibility to crown rot were inoculated with a mixture of F. pseudograminearum isolates. Seedlings were harvested from 7 to 42 days after inoculation and expanded plant parts were rated for severity of visible disease symptoms. Individual leaf sheaths were placed onto nutrient media and fungal colonies emerging from the leaf sheathes were counted to estimate the degree of fungal spread within the host tissue. Significant differences in both the timing and the severity of disease symptoms were observed in the leaf sheath tissues of different host genotypes. Across all genotypes and plant parts examined, the development of visible symptoms closely correlated with the spread of the fungus into that tissue. The degree of infection of the coleoptile and sub-crown internode varied between genotypes, but was unrelated to the putative resistance of the host. In contrast leaf sheath tissues of the susceptible barley cv. Tallon and bread wheat cv. Puseas scored higher disease ratings and consistently showed faster, earlier spread of the fungus into younger tissues than infections of the oat cv. Cleanleaf or the wheat lines 2-49 and CPI 133814. While initial infections usually spread upwards from near the base of the first leaf sheath, the pathogen did not appear to invade younger leaf sheaths only from the base, but rather spread laterally across from older leaf sheaths into younger, subtended leaf sheaths, particularly as disease progressed. Early in the infection of each leaf sheath, disease symptoms in the partially resistant genotypes were less severe than in susceptible genotypes, however as infected leaf sheaths aged, differences between genotypes lessened as disease symptoms approached maximum values. Hence, while visual scoring of disease symptoms on leaf sheaths is a reliable comparative measure of the degree of fungal infection, differences between genotypes in the development of disease symptoms are more reliably assessed using the most recently expanded leaf sheaths.

The water relations and irrigation requirements of lychee (litchi chinensis sonn.): a review

The results of research into the water relations and irrigation requirements of lychee are collated and reviewed. The stages of plant development are summarised, with an emphasis on factors influencing the flowering process. This is followed by reviews of plant water relations, water requirements, water productivity and, finally, irrigation systems. The lychee tree is native to the rainforests of southern China and northern Vietnam, and the main centres of production remain close to this area. In contrast, much of the research on the water relations of this crop has been conducted in South Africa, Australia and Israel where the tree is relatively new. Vegetative growth occurs in a series of flushes. Terminal inflorescences are borne on current shoot growth under cool (<15 °C), dry conditions. Trees generally do not produce fruit in the tropics at altitudes below 300 m. Poor and erratic flowering results in low and irregular fruit yields. Drought can enhance flowering in locations with dry winters. Roots can extract water from depths greater than 2 m. Diurnal trends in stomatal conductance closely match those of leaf water status. Both variables mirror changes in the saturation deficit of the air. Very little research on crop water requirements has been reported. Crop responses to irrigation are complex. In areas with low rainfall after harvest, a moderate water deficit before floral initiation can increase flowering and yield. In contrast, fruit set and yield can be reduced by a severe water deficit after flowering, and the risk of fruit splitting increased. Water productivity has not been quantified. Supplementary irrigation in South-east Asia is limited by topography and competition for water from the summer rice crop, but irrigation is practised in Israel, South Africa, Australia and some other places. Research is needed to determine the benefits of irrigation in different growing areas. Copyright © Cambridge University Press 2013.

Acute and chronic effects of dietary nitrate supplementation on blood pressure and the physiological responses to moderate-intensity and incremental exercise

Dietary nitrate (NO3−) supplementation with beetroot juice (BR) over 4–6 days has been shown to reduce the O2 cost of submaximal exercise and to improve exercise tolerance. However, it is not known whether shorter (or longer) periods of supplementation have similar (or greater) effects. We therefore investigated the effects of acute and chronic NO3− supplementation on resting blood pressure (BP) and the physiological responses to moderate-intensity exercise and ramp incremental cycle exercise in eight healthy subjects. Following baseline tests, the subjects were assigned in a balanced crossover design to receive BR (0.5 l/day; 5.2 mmol of NO3−/day) and placebo (PL; 0.5 l/day low-calorie juice cordial) treatments. The exercise protocol (two moderate-intensity step tests followed by a ramp test) was repeated 2.5 h following first ingestion (0.5 liter) and after 5 and 15 days of BR and PL. Plasma nitrite concentration (baseline: 454 ± 81 nM) was significantly elevated (+39% at 2.5 h postingestion; +25% at 5 days; +46% at 15 days; P < 0.05) and systolic and diastolic BP (baseline: 127 ± 6 and 72 ± 5 mmHg, respectively) were reduced by ∼4% throughout the BR supplementation period (P < 0.05). Compared with PL, the steady-state V̇o2 during moderate exercise was reduced by ∼4% after 2.5 h and remained similarly reduced after 5 and 15 days of BR (P < 0.05). The ramp test peak power and the work rate at the gas exchange threshold (baseline: 322 ± 67 W and 89 ± 15 W, respectively) were elevated after 15 days of BR (331 ± 68 W and 105 ± 28 W; P < 0.05) but not PL (323 ± 68 W and 84 ± 18 W). These results indicate that dietary NO3− supplementation acutely reduces BP and the O2 cost of submaximal exercise and that these effects are maintained for at least 15 days if supplementation is continued.