In the dryland cropping areas of southern Australia, at risk from dryland salinity, tree belts can improve water management by taking up water unused by crops, with the risk that crop yield will be reduced through competition. As there are few direct markets for tree products grown in the medium to low rainfall areas, the design of agroforestry systems becomes important in reducing the trade-off in crop yield. This study examined some factors that influence the trade-off between crop yield and deep-drainage control in order to develop design guidelines for medium to low rainfall agroforestry. Twenty-one sites in the grain-growing region of Western Australia and southern New South Wales were surveyed over 2 years for crop yields, tree leaf area index, and estimated recharge, providing data from 32 tree–crop interfaces on the relative influence of environmental factors and farming system characteristics on the trade-off between water management and crop yield. The factors most strongly correlated with higher yields were water-gaining sites, orientation that provided shelter from southerly to north-westerly (S, SW, W, NW) winds, and tree age (<10 years). The factors most strongly correlated with the area of cropped land protected against deep drainage were tree age (>10 years), lighter soil types, and low rainfall (<400 mm). Economic analysis of the trade-off required to produce a particular deep-drainage reduction target produced 3 groups of sites: (1) those where trees resulted in a gross margin increase of $15/ha and an estimated deep-drainage reduction of 52% (n = 3), (2) those with a gross margin loss of $49/ha and estimated deep-drainage reduction of 47% (n = 11), and (3) those with a gross margin loss of $163/ha and a deep-drainage reduction of 37% (n = 18). None of the 3 sites in the first group were in the most favourable class in both years, highlighting the vulnerability of a relatively fixed farming system to climate variability.

This research investigated the potential to domesticate an Australian native grass (Microlaena stipoides) to produce a perennial grain crop. Perennial grain crops offer a new solution to the long-standing problems of salinity and soil erosion associated with conventional cropping systems based on annual plants. Seed yield and its components (culm number, spikelet number per culm, seed set, seed weight) were measured in 46 accessions of Microlaena stipoides (microlaena, meadow or weeping rice grass) from Western Australia and New South Wales to quantify potentially useful variation in the species. A high degree of variability was found to exist, with a 20-fold range in seed yield (0.1-2.4 g/plant), 5-fold range in seed weight (129-666 mg per 100 seeds), 2-fold range in spikelet number (14-30 per culm), 8-fold range in seed set (12-98%), and a 5-fold range in culm number (11-59 per plant). Seed yield was positively and significantly (P<0.05) correlated with culm number, seed set, and seed weight (r>0.55 for all). No correlation was found between seed yield and spikelet number per culm (r=-0.14). The range in seed yield and its components suggests that there is sufficient variation within microlaena to make selections for higher yielding lines. This variation will enable breeders to exploit genetic diversity more efficiently and identify useful accessions for further work. High priority traits for future work include synchronous maturity and resistance to shattering.

We studied the adaptation of narrow-leafed lupin (Lupinus angustifolius) and yellow lupin (L. luteus) to waterlogging because yellow lupin may have potential as a new legume crop for coarse-textured, acidic, waterlogging-prone areas in Western Australia. In a controlled environment, plants were waterlogged for 14 days at 28 or 56 days after sowing (DAS). Plants were more sensitive when waterlogged from 56 to 70 DAS than from 28 to 42 DAS, root growth was more sensitive than shoot growth, and leaf expansion was more sensitive than leaf dry weight accumulation. Waterlogging reduced the growth of narrow-leafed lupin (60–81%) more than that of yellow lupin (25–56%) and the response was more pronounced 2 weeks after waterlogging ceased than at the end of waterlogging. Waterlogging arrested net root growth in narrow-leafed lupin but not in yellow lupin, so that after 2 weeks of recovery the root dry weight of yellow lupin was the same as that of the control plants but in narrow-leafed lupin it was 62% less than the corresponding control plants. Both species produced equal amounts of hypocotyl root when waterlogged from 28 to 42 DAS but yellow lupin produced much greater amounts than narrow-leafed lupin when waterlogged from 56 to 70 DAS.

This study determined whether the tolerance of yellow lupin to waterlogging, observed in experiments in controlled environments, occurs under field conditions. Of particular interest is the impact of waterlogging on the distribution of roots because lupin is exposed to terminal drought in the south of Western Australia, which in itself can have a profound effect on yield. A field experiment was undertaken in the central grain-growing region of Western Australia near Beverley using hydraulically isolated plots to impose and remove waterlogging in a duplex soil. The responses of root and shoot growth of narrow-leafed and yellow lupin to waterlogging in the field were similar to those observed in the controlled environment experiments. In the field experiment, waterlogging had no effect on seed yield of yellow lupin but reduced it by 61% in narrow-leafed lupin. Waterlogging more than halved the dry weight of narrow-leafed lupin but reduced it by only 19% in yellow lupin. In yellow lupin, yield was 3.4 t/ha with waterlogging and 3.8 t/ha without waterlogging, compared with 1.4 t/ha with waterlogging and 3.5 t/ha without waterlogging in narrow-leafed lupin. Waterlogging had no effect on the harvest index of yellow lupin (0.26) but reduced it from 0.36 to 0.31 in narrow-leafed lupin. The larger effect of waterlogging on the yield of narrow-leafed lupin was mainly attributable to fewer pods.Net root growth ceased during waterlogging in both species. After waterlogging, roots of yellow lupin grew at a similar rate to the controls, whereas roots of narrow-leafed lupin grew at a much slower rate than the controls. Waterlogging halved the root density of yellow lupin at 25 cm depth and almost eliminated the roots of narrow-leafed lupin at this depth. After waterlogging, root production in the surface 10 cm increased to about 0.5 cm/cm(3) in yellow lupin but to 0.2 cm/cm(3) in narrow-leafed lupin. At depth (> 20 cm), roots of waterlogged yellow lupin continued to grow while those of waterlogged narrow-leafed lupin grew little, if at all. Yellow lupin tolerated waterlogging in the field better than narrow-leafed lupin because it re-established its root system at depth after waterlogging was removed and it produced more fertile pods.

Yellow lupin (Lupinus luteus) may have potential as a legume crop in waterlogging-prone areas of Western Australia. To elucidate the physiological response of yellow lupin and the widely grown narrow-leafed lupin (L. angustifolius) to transient waterlogging we conducted experiments in controlled environments. Narrow-leafed lupin and yellow lupin were grown in pots and waterlogged for 14 days from 28 to 42, or 56 to 70 days after sowing, each being followed by a 14-day recovery period. Root and shoot growth responses, leaf gas exchange, water relations, and N accumulation were assessed. During the period of waterlogging, net nitrogen accumulation ceased in both species at both ages. During recovery, yellow lupin accumulated more nitrogen than narrow-leafed lupin. Waterlogging reduced leaf gas exchange more with older plants than with younger plants, and more so with narrow-leafed lupin than yellow lupin. Some components of leaf gas exchange, particularly leaf conductance, were reduced by up to 80%. Waterlogging had no effect on leaf water potential of yellow lupin but reduced it in narrow-leafed lupin, from about –450 to –1100 kPa, especially during the recovery period. Yellow lupin was more adapted to transient waterlogging than narrow-leafed lupin because it maintained its leaf water status, it accumulated more nitrogen during recovery, and its photosynthetic activity recovered quickly afterremoval of waterlogging.

To understand how yellow lupin tolerates waterlogging better than narrow-leafed lupin, we investigated the roles of the roots and the shoots of these species. Reciprocal- and self-grafted combinations (scion = shoot/rootstock) of yellow and narrow-leafed lupin were made at the 2-leaf stage and waterlogged 45 days later (8–10 leaf stage). Responses to waterlogging were examined at the end of waterlogging and following a recovery period of 14 days.Waterlogging of reciprocal and self-grafted plants reduced total plant dry weight by 15–58% compared with non-waterlogged controls. These reductions were greater when the rootstock was narrow-leafed rather than yellow lupin, and were similar for the roots and shoots. Waterlogging increased dry weight of hypocotyl roots in most grafting combinations (by 2–19-fold), but grafts with narrow-leafed lupin scions produced almost twice the hypocotyl root length of grafts with yellow lupin scions. During the waterlogging period, leaf gas exchange decreased by 16–74% in all grafting combinations except in narrow-leafed lupin scion/yellow lupin rootstock where it increased by 17–30%. During waterlogging, stem water potential decreased and leaf osmotic pressure increased. These changes compensated one another and consequently there was no effect on bulk leaf turgor. After 14 days recovery, water relations returned to initial values. Tolerance of the whole plant to waterlogging was influenced more by the root genotype than the shoot genotype. However, production of hypocotyl roots in response to waterlogging was related to the shoot genotype rather than the root genotype.

3-Methoxytyramine (3-MT), normally a minor metabolite of 3,4-dihydroxyphenylethylamine (dopamine) in brain, becomes the sole product of metabolism following the administration of a monoamine oxidase (MAO) inhibitor. A simplified reverse-phase HPLC method for 3-MT employing electrochemical detection is fully described. This method has a detection limit of 0.1 microgram/g brain wet weight and is sensitive enough to detect 3-MT in individual brain regions after rats have been pretreated with an MAO inhibitor. Administration of tranylcypromine (TCP, 10 mg/kg) and L-3,4-dihydroxyphenylalanine (L-DOPA) (10-50 mg/kg) produced a dose-dependent linear increase in 3-MT concentrations in the dopaminergic brain regions n. caudatus (r = 0.95; p less than 0.01) and n. accumbens (r = 0.96; p less than 0.01). This treatment also produced a dose-dependent increase in behavioural activity in rats (r = 0.88; p less than 0.01). Furthermore, a good correlation was found between the activity responses of individual rats and the accumulation of 3-MT after TCP/L-DOPA in both n. caudatus (r = 0.76; p less than 0.01) and n. accumbens (r = 0.84; p less than 0.01). These data describe a simple and sensitive HPLC analysis technique for 3-MT and demonstrate that following administration of an MAO inhibitor this metabolite may provide a useful monitor of central dopamine function.

In the past, radar ESM systems have relied on operator interpretation of measured parameters to provide classification and identification of emitters. However, for rapid response in the dense electromagnetic environments encountered in modern warfare, automatic processing and decision-making techniques are required. In order to identify individual emitters, their pulse trains must be deinterleaved. Various approaches to deinterleaving are discussed, and the relative merits of emitter parameters for each method are identified. Since it is impossible to totally avoid data corruption before the sorting process, the system design must take this into account.

Four laboratories have tested motorettes specially prepared by a fifth, using a similar procedure to that recommended in AIEE 510 (IEEE 117). Heat aging was at 200°C and a 2.3: 1 difference in measured life was obtained between laboratories. Consideration of possible variations in procedure and testing have failed to establish any specific causes for the differences in the results, and it is concl...