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A range of annual legume genotypes comprising one line of Trifolium subterraneum, four lines of T. michelianum, 11 of T. resupinatum var. resupinatum, and one line of T. resupinatum var. majus were grown in glasshouses under temperature regimes of 10−15°C and 16−21°C. Dry matter (DM) weights of stem, leaf, and flower tissues were measured when plants had six nodes, at first flower appearance, and at senescence. All samples were scanned by near-infrared reflectance spectroscopy (NIRS). One-third of the samples, covering the range of spectral characteristics, were analysed for in vitro digestible organic matter (DOMD), organic matter, crude protein (CP), neutral detergent fibre (NDF), lignin, cellulose, and the hemicellulosic polysaccharide monomers arabinose, xylose, mannose, galactose, and rhamnose. These data were used to develop calibration equations from which the composition of the remaining samples was predicted by NIRS. The higher temperature resulted in plants reaching respective phenological stages earlier, but did not affect either DM yields of total plant, stem, leaf, and petiole tissues or the proportions of each fraction. In vitro DOMD and arabinose and galactose levels decreased, while lignin, cellulose, NDF, xylose, mannose, and rhamnose levels increased with advancing maturity. In vitro DOMD was positively associated with contents of CP, arabinose, galactose, and the arabinose/xylose ratio and was negatively associated with contents of lignin, cellulose, NDF, xylose, mannose, and rhamnose. Lignin contents were highly correlated with levels of both xylose and mannose. Stems were more digestible than leaves in subterranean clover and T. resupinatum var. majus. The study also demonstrated that NIRS can be used routinely as a quick, inexpensive, and reliable laboratory technique to predict feed components of annual Trifolium legumes.

A low-cost mobile load cell-based weighing device is described for use in experiments that involve measuring water use by container-grown trees. The relatively lightweight (~30 kg) mobile weighing device was constructed from strong, corrosion-resistant materials readily available from commercial sources. The device has a total weighing capacity of 500 kg on the basis of rated capacity of 250 kg from each of two load cells and a maximum resolution of 0.020 kg. On the basis of a soil surface area of 825 cm2 for the containers used in the proving study, this sensitivity corresponded to an equivalent water depth of 0.23 mm.

The longevity of Grevillea ‘Sylvia’ inflorescences can be very short and is influenced by exposure to ethylene. Gibberellic acid has the potential to delay senescence in some cut flowers by acting as an anti-ethylene treatment. Gibberellic acid was therefore applied to Grevillea ‘Sylvia’ inflorescences in vase solutions to determine its effects on longevity. Treatments with gibberellic acid did not prolong the longevity of inflorescences or influence 1-aminocyclopropane-1-carboxylic acid concentrations. Treatments at high gibberellic acid concentrations enhanced flower abscission and we therefore conclude that vase-applied gibberellic acid treatments are not suitable for extending the longevity of cut Grevillea ‘Sylvia’ inflorescences.

Litchi (Litchi chinensis Sonn.) is a tropical to subtropical crop that originated in South-East Asia. Litchi fruit are prized on the world market for their flavour, semi-translucent white aril and attractive red skin. Litchi is now grown commercially in many countries and production in Australia, China, Israel, South Africa and Thailand has expanded markedly in recent years. Increased production has made significant contributions to economic development in these countries, especially those in South-East Asia. Non-climacteric litchi fruit are harvested at their visual and organoleptic optimum. They are highly perishable and, consequently, have a short life that limits marketability and potential expansion of demand. Pericarp browning and pathological decay are common and important defects of harvested litchi fruit. Postharvest technologies have been developed to reduce these defects. These technologies involve cooling and heating the fruit, use of various packages and packaging materials and the application of fungicides and other chemicals. Through the use of fungicides and refrigeration, litchi fruit have a storage life of about 30 days. However, when they are removed from storage, their shelf life at ambient temperature is very short due to pericarp browning and fruit rotting. Low temperature acclimation or use of chitsoan as a coating can extend the shelf life. Sulfur dioxide fumigation effectively reduces pericarp browning, but approval from Europe, Australia and Japan for this chemical is likely to be withdrawn due to concerns over sulfur residues in fumigated fruit. Thus, sulfur-free postharvest treatments that maintain fruit skin colour are increasingly important. Alternatives to SO2 fumigation for control of pericarp browning and fruit rotting are pre-storage pathogen management, anoxia treatment, and dipping in 2% hydrogen chloride solution for 6−8 min following storage at 0°C. Insect disinfestation has become increasingly important for the expansion of export markets because of quarantine issues associated with some fruit fly species. Thus, effective disinfestation protocols need to be developed. Heat treatment has shown promise as a quarantine technology, but it injures pericarp tissue and results in skin browning. However, heat treatment can be combined with an acid dip treatment that inhibits browning. Therefore, the primary aim of postharvest litchi research remains the achievement of highly coloured fruit which is free of pests and disease. Future research should focus on disease control before harvest, combined acid and heat treatments after harvest and careful temperature management during storage and transport.

Cut Geraldton waxflower (Chamelaucium uncinatum Schauer) flowers are often infected with Botrytis cinerea. Release of infection from quiescence can cause ethylene production by invaded host tissues and result in flower abscission. Postharvest floral organ abscission is a major problem for the commercial waxflower industry. Methyl jasmonate (MeJA) occurs naturally in plant tissue and has a signalling role in eliciting induced systemic resistance against disease. MeJA treatments have been shown to suppress B. cinerea infecting cut rose flowers. The present experiments investigated the potential of exogenous MeJA treatments for B. cinerea management on harvested waxflower. MeJA treatments of 10 and 100 µL liquid MeJA/L of air applied to cv. Purple Pride and 1 µL MeJA/L to cv. Mullering Brook gave reductions in disease severity for uninoculated stems. However, concentrations of 100 µL MeJA/L applied to Purple Pride in addition to 1 and 10 µL MeJA/L applied to Mullering Brook increased the incidence of floral organ fall. Flower abscission upon treatment with MeJA may be due to induced systemic resistance-associated upregulation of ethylene biosynthesis. MeJA treatments had no direct effect on B. cinerea hyphal elongation in vitro. Collectively, these results show that while MeJA treatment may elicit defence in waxflower against Botrytis, the chemical also causes floral organ fall. Thus, exogenous MeJA treatments do not have potential for B. cinerea management on harvested waxflower.

Postharvest abscission of Geraldton waxflower (Chamelaucium uncinatum Schauer) flower buds and flowers is ethylene-mediated. Exposure of floral organs to exogenous ethylene (1 mu L L-1) for 6 h at 20 degrees C induced separation at a morphologically and anatomically distinct abscission zone between the pedicel and. oral tube. Flower buds with opening petals and flowers with a nectiferous hypanthium were generally more responsive to exogenous ethylene than were flower buds enclosed in shiny bracteoles and aged (senescing) flowers. The anatomy of abscission-zone cells did not change at sequential stages of floral development from immature buds to aged flowers. The zone comprised a layer of small, laterally elongated-to-rounded, closely packed and highly protoplasmic parenchyma cells. Abscission occurred at a two- to four-cell-wide separation layer within the abscission zone. The process involved degradation of the middle lamella between separation layer cells. Following abscission, cells on both the proximal and distal faces of the separation layer became spherical, loosely packed and contained degenerating protoplasm. Central vascular tissues within the surrounding band of separation layer cells became torn and fractured. For flower buds, bracteoles that enclose the immature floral tube also separated at an abscission zone. However, this secondary abscission zone appeared less sensitive to ethylene than the primary ( central). oral-tube abscission zone as bracteoles generally only completely abscised when exposed to 10 mu L L-1 ethylene for the longer period of 24 h at 20 degrees C. The smooth surfaces of abscised separation-layer cells suggest that hydrolase enzymes degrade the middle lamella between adjacent cell walls.

Naturally occurring elemental signatures (or composition) of otoliths may enable aquaculture and wild-caught yellowtail kingfish (Seriola lalandi) to be distinguished from one another, so that in the event of aquaculture escapes, escaped fish could be identified. Yellowtail kingfish were obtained from aquaculture ventures in three regions of Spencer Gulf and from nine areas external to aquaculture throughout the inner and outer Spencer Gulf, South Australia. Elemental signatures (Mg, Mn, Sr, Ba) of otoliths were analysed via LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometry). A highly significant difference was detected between elemental signatures of the aquaculture and wild-caught fish, but this difference was largely attributable to wild fish from Port Augusta being different from the other groupings. For individual elements, it was difficult to detect differences between aquaculture and wild-caught fish, as there was considerable variation between locations within each group. When comparisons between aquaculture and wild fish were made of the inner and outer Spencer Gulf, aquaculture fish could be distinguished from wild fish and classified correctly with a high degree of accuracy (82–100%); the same level of accuracy was not achieved with wild fish. Comparison of elemental transects showed considerable variability between locations, with no features distinguishing aquaculture or wild-caught fish. It would be beneficial to combine naturally occurring signatures with other identification approaches (e.g. artificial elemental signatures) to accurately distinguish aquaculture from wild-caught fish. The impacts of escaped fish could then be determined.

Botrytis cinerea is the major pathogen infecting cut freesia flowers. Flecking symptoms on petals caused by this fungus result in postharvest rejections and substantial economic loss to both growers and sellers. In a limited survey for industry, numbers of freesia stems sent from a specialist grower in The Netherlands and rejected at a cut flower wholesaler in the United Kingdom were documented. Relationships between preharvest environment conditions in Holland that may predispose flowers to infection and postharvest freesia rejection levels in the United Kingdom due to B. cinerea flecking symptom expression are reported. Freesia rejections peaked during spring and, to a lesser degree, autumn periods. However, no clear correlations between preharvest growing environment conditions (e.g. 3-day means for temperature preceding harvest) and postharvest rejection frequency (%) could be discerned. Thus, sporadic freesia rejections in the United Kingdom were probably attributable either to other unresolved variables during the pre- (e.g. infection pressure) and/or postharvest (e.g. condensation events) phases or to interactions among predisposing variables.

The plant growth regulator abscisic acid induces stomatal closure, which can reduce transpiration rate and extend vase life of cut flowers by maintaining a positive water balance. Analytical-reagent grade abscisic acid is, however, expensive. In this work, the effects of 2 potentially inexpensive synthetic analogues of abscisic acid were studied as to their effects on cut Baccara roses. Abscisic acid and its analogues PBI-365 and PBI-429 reduced transpiration and helped to increase fresh weight during the first few days of vase life. However, the reduction in transpiration rate brought about by abscisic acid and the analogues did not alter vase life. Sucrose in the vase solution at concentrations of 2 and 4% increased vase life of cut Baccara roses. However, the highest sucrose concentration (4%) caused leaf crisping, thereby reducing the quality of the flower stems. Abscisic acid and the analogue PBI-365 reduced this phytotoxicity by induction of stomatal closure and reduction of vase solution sucrose flux into the leaves.

Rapid deterioration is a problem with minimally processed pineapple fruit. Effects of 1-methylcyclopropene treatment with or without ascorbic acid treatment on respiration rate, browning and other quality parameters were investigated for minimally processed fruit stored at 4.5°C for 12 days in air. 1-methylcyclopropene treatment reduced respiration rate and browning, and maintained more acceptable visual quality in pineapple fruit slices. 1-methylcyclopropene-treated pineapple fruit slices reached an unacceptable visual quality level after day 8. In contrast, untreated slices were unacceptable after 4 days storage. Respiration rate was reduced from about 5.8 mL CO2/kg.h in control fruit to about 4.8–5.0 mL CO2/kg.h in 1-methylcyclopropene-treated fruit at 12 days. Lightness of control pineapple slices reduced from L* 77 to 65 over 12 days, while 1-methylcyclopropene-treated fruits remained at about L* 72. 1-methylcyclopropene treatment increased electrolyte leakage from pineapple slices. Apart from further suppression of respiration rate, there was no benefit of using 1-methylcyclopropene at above 1.0 μL/L. 1-methylcyclopropene treatment reduced ascorbic acid loss from 44% for untreated fruit to 29% for 1-methylcyclopropene-treated fruit at the end of the 12-day storage. An additive effect of 1-methylcyclopropene treatment was recorded for pineapple fruit slices dipped in 2% (w/v) ascorbic acid solution for 3 min. Ascorbic acid treatment resulted in reduced browning, electrolyte leakage and fruit softening. Therefore, 1-methylcyclopropene treatment helps maintain the quality of minimally processed pineapple fruit at least partially by reducing the hydrolysis of endogenous ascorbic acid.

Intracellular inclusions in the pedicel and calyx-tube tissues of Chamelaucium uncinatum Schauer (Myrtaceae) flowers are irregular in shape. They were shown, by polarised light and scanning electron microscopy, to be birefringent 8.9–29.5 μm druse (i.e. aggregate) crystals. Energy-dispersive X-ray spectroscopy showed that these crystals were predominantly composed of calcium. Histochemical and acid-solubility tests indicated that the crystals were calcium oxalate. Raman microprobe spectroscopy was used to confirm this chemical identity. The calcium oxalate crystals were located in xylem-vessel lumens and also in parenchyma cells adjacent to vascular tissues. Thus, the crystals may function to regulate soluble calcium concentrations in C. uncinatum tissues near sites where calcium is unloaded from the xylem.

Postharvest flower abscission from cut Geraldton waxflower (Chamelaucium uncinatum) is mostly caused by fungal invasion. Elevated plant tissue calcium concentrations through postharvest application reduces fungal disease severity in various crops. Such results may be explained by strengthening of plant cell walls by calcium. Strengthening provides a structural barrier to fungal hyphae, thereby restricting invasion of plant cells. Postharvest pulsing with calcium solution substantially increased calcium concentrations in waxflower tissues. 45Ca�tracer revealed calcium distribution throughout flowering sprigs, including infection sites such as stylar tissue. However, pulsing waxflower sprigs with calcium did not suppress either disease or flower abscission, nor did it enhance vase life.

Physicochemical gradients occur in mango mesocarp tissue during ripening. These gradients are reflected in water activity, which is non-uniform throughout the mesocarp. Signal intensity in proton magnetic resonance images (first echo, proton density and T2) for green-mature `Kensington Pride' mesocarp tissue was highest near the endocarp and lowest near the exocarp. Relative signal intensity increased in the middle mesocarp as ripening proceeded, but remained relatively low in the outer mesocarp. T2 relaxation times for inner and middle mesocarp regions fell during ripening. The data suggest that water activity in the mesocarp tissue increased in an outward-moving flux as ripening progressed. This change in water activity was associated with starch hydrolysis and other ripening-related processes that commence near the endocarp.

Geraldton waxflower (Chamelaucium uncinatum Schauer) is Australia's most economically important cut-flower export. Its small, attractive flowers make it particularly suitable as a filler in floral arrangements. However, postharvest bud and flower abscission is a major problem during transport, handling and marketing. Abscission may be caused by wound-induced endogenous ethylene production brought about by flower tissue infection with fungal pathogens such as Botrytis cinerea. Botany and postharvest characteristics are discussed in relation to flower abscission and how resultant postharvest losses may be minimised.

Saprophytic bacteria, yeasts and filamentous fungi were isolated from Geraldton waxflower flowers and screened to identify potential antagonism towards Botrytis cinerea. Isolates from other sources (e.g. avocado) were also tested. Isolates were initially screened in vitro for inhibition of B. cinerea conidial germination, germ tube elongation and mycelial growth. The most antagonistic bacteria, yeasts and fungi were selected for further testing on detached waxflower flowers. Conidia of the pathogen were mixed with conidia or cells of the selected antagonists, co-inoculated onto waxflower flowers, and the flowers were sealed in glass jars and incubated at 20˚C. The number of days required for the pathogen to cause flower abscission was determined. The most antagonistic bacterial isolate, Pseudomonas sp. 677, significantly reduced conidial germination and retarded germ tube elongation of B. cinerea. None of the yeast or fungal isolates tested was found to significantly reduce conidial germination or retard germ tube elongation, but several significantly inhibited growth of B. cinerea. Fusarium sp., Epicoccum sp. and Trichoderma spp. were the most antagonistic of these isolates. Of the isolates tested on waxflower, Pseudomonas sp. 677 was highly antagonistic towards B. cinerea and delayed waxflower abscission by about 3 days. Trichoderma harzianum also significantly delayed flower abscission. However, as with most of the fungal antagonists used, inoculation of waxflower flowers with this isolate resulted in unsightly mycelial growth.

The potential for the ethylene binding inhibitor, 1-methylcyclopropene, to delay ripening of ‘Hass’ avocado, ‘African Pride’ custard apple, ‘Kensington Pride’ mango and ‘Solo’ papaya was examined. Fruit were gassed with 25 µL/L 1-methylcyclopropene for 14 h at 20°C, followed by treatment with 100 µL/L ethylene for 24 h, and then ripened at 20°C. Ethylene treatment alone generally halved the number of days for fruit to reach the ripe stage, compared with untreated fruit. 1-Methylcyclopropene treatment alone increased the number of days to ripening by 4.4 days (40% increase), 3.4 days (58%), 5.1 days (37%) and 15.6 days (325%) for avocado, custard apple, mango and papaya, respectively, compared with untreated fruit. Applying 1-methylcyclopropene to the fruit before ethylene prevented the accelerated ripening normally associated with ethylene treatment, so that the number of days to ripening for fruit treated with 1-methylcyclopropene plus ethylene was similar to the number of days to ripening for fruit treated with 1-methylcyclopropene alone. 1-Methylcyclopropene treatment was associated with slightly higher severity of external blemishes in papaya and custard apple, slightly higher rots severity in avocado, custard apple and papaya, and at least double the severity of stem rots in mango, relative to fruit not treated with 1-methylcyclopropene. Thus, 1-methylcyclopropene treatment has the potential to reduce the risk of premature ripening of avocado, custard apple, mango and papaya fruit due to accidental exposure to ethylene. However, additional precautions may be necessary to reduce disease severity associated with 1-methylcyclopropene treatment.

Relationships were examined between environmental conditions mediated by packaging and handling and the deterioration of harvested Geraldton waxflower cv. ‘Fortune Cookie’. Disease severity plus flower and leaf drop caused by inoculation with Botrytis cinerea were reduced by lowering handling temperatures to 0, 5 or 5/20˚C alternated daily, versus 20˚C. They were also reduced by inhibition of ethylene action with a silver thiosulfate pulse pretreatment. Additionally, treatments that enhanced water loss, such as packing dry, keeping forced air-cooling holes open and strategic placement of extra ventilation holes may also reduce disease severity and flower plus leaf fall. Inclusion of KMnO4 -based Bloomfresh ethylene scrubbing sachets in packages did not reduce disease severity or lessen flower plus leaf fall. Thus, deterioration of waxflower packaged in commercial cartons can be minimised by keeping temperatures low, packing plant material dry, use of cartons with strategically placed ventilation holes and/or pretreatment with silver thiosulfate.

This study investigated treatment of mango (Mangifera indica L.) fruit with 2 host defence-promoting compounds for suppression of anthracnose disease (Colletotrichum gloeosporioides). Cultivar ‘Kensington Pride’ fruit were treated at concentrations of up to 1000 mg/L with either potassium phosphonate or salicylic acid. Applications were by various combinations of pre- and postharvest dips and vacuum infiltration. Postharvest treatments at up to 2000 mg/L salicylic acid were evaluated in a second fruiting season. Fruit were either uninoculated or inoculated with the fungal pathogen. Colour, firmness and disease-severity were assessed during shelf life at 23°C. There were no significant (P>0.05) effects of potassium phosphonate or salicylic acid on anthracnose disease severity in the first season. Moreover, phosphonate or salicylic acid treatment did not significantly affect fruit colour or firmness changes. There were significant (P

Effects on vase life and chlorophyll fluorescence were evaluated for kangaroo paw Bush Dawn flowers harvested from 3 growth environments and kept at 3 storage temperatures for 4 storage periods. Flowers were grown in a glasshouse, shadehouse and in the open. Harvested flowers were stored at 0, 7.5 or 13°C for 1, 2, 3 or 4 weeks. Minimum fluorescence values decreased progressively from 0.103 to 0.078 as storage temperatures increased from 0 to 13°C. Relative fluorescence ratios of stored kangaroo paw flowers were altered significantly in response to storage temperature, storage duration and growth environment. Relative fluorescence ratios decreased progressively from 0.778 to 0.649 with increasing storage duration from 1 to 4 weeks. Relative fluorescence values were 0.688, 0.784 and 0.711 for 0, 7.5 and 13°C storage temperatures, respectively. Minimum fluorescence did not differ among the growth environments, but relative fluorescence was highest for the shadehouse (0.760) and lowest for the open (0.695). Vase life was also influenced by storage temperature, storage duration and flower source. Main effect vase lives of flowers were 6.6, 7.2 and 3.4 days for 0, 7.5 and 13°C storage temperatures, respectively. Shorter vase life after storage at 0 than at 7.5°C indicates that Bush Dawn is chilling sensitive. Post-storage longevity of flowers from the shadehouse (6.5 days) and glasshouse (6.3 days) was greater than from the open (4.2 days). Relative fluorescence values, which decreased in a linear manner for all storage temperatures as storage duration increased, were significantly correlated with the vase life.

Premature ripening and/or senescence and abscission induced by exposure to ethylene are significant postharvest problems. Banana fruit and grevillea and Geraldton waxflower flowers are among affected commodities. Treatment with 1-methylcyclopropene gas or silver thiosulfate liquid can be used to prevent ethylene perception and response. Treatment of banana fruit with 10 nL 1-methylcyclopropene/L for 12 h at 20 degrees C afforded protection against subsequent serial treatments over 13 days of subsets with 100 mu L ethylene/L for 24 h at 20 degrees C. Protection of Grevillea 'Sylvia' inflorescences was effective only for 2 days. Thereafter, fruit and inflorescences regained sensitivity to ethylene. In contrast, neither banana fruit nor grevillea inflorescences treated with 10 nL 1-methylcyclopropene/L for 12 h at 2 degrees C were protected against ethylene. 1-Methylcyclopropene binding to ethylene receptors was apparently not achieved at the lower temperature. Increasing the 1-methylcyclopropene concentration to 100 nL/L, applied at 2.5 degrees C to banana fruit, achieved protection against ethylene. Waxflower sprigs treated with 10 nL 1-methylcyclopropene/L for 12 h at 2 or 20 degrees C regained full sensitivity to ethylene after about 2 and 4 days, respectively. In contrast, pulsing waxflower with 0.5 mmol Ag+/L as silver thiosulfate for 12 h at 2 or 20 degrees C afforded protection against ethylene for the 10 days duration of the experiment.

This is the first report of experimentation aimed at developing a postharvest glycerol uptake treatment protocol for juvenile-form Eucalyptus cinerea foliage. Glycerol uptake and accumulation were monitored and the protocol was varied by adding the surfactant nonylphenolpolyglycol ether (Agral-600) to the preservation solution. Visual characteristics of preserved unhardened (soft or immature) and hardened (mature) foliage were assessed. Foliage respiration rate was monitored during treatment to establish when metabolic function ceased. Glycerol proved a suitable preservative for E. cinerea foliage, with 20% (v/v) solution being as effective as 30% solution. Addition of Agral-600 did not improve uptake and, in fact, lead to excessive drying of leaves. Hardened foliage was more suitable for treatment than unhardened, since it retained better colour and exhibited less tip wilt. Measurable respiration ceased within 1.5 days of commencing treatment with glycerol. Solution uptake was markedly reduced 2 days after treatment began, indicating failure of transpiration. Thus, metabolic functions ceased 1.5–2 days after uptake preservation commenced.

Summary. Treatment of cut flowering Boronia heterophylla (red boronia) stems with 10 L ethylene/L for 72 h at 20°C induced flower senescence and abscission, and thereby reduced stem fresh weight and vase life. Pre-treatment with 1-methylcyclopropene (1-MCP) reduced these ethylene effects. Treatment of B. heterophylla with 10 L ethylene/L for a shorter 12 h period at 20°C did not affect vase life. Rates of endogenous ethylene production by B. heterophylla flowers increased in association with wilting during flower senescence.

Bagging mango fruit during their development on the tree can reduce insect and disease damage. However, it is also possible that bagging can interfere with transpiration and associated calcium accumulation. Low calcium concentrations have been correlated with poor mango fruit quality. This study was conducted to evaluate the influence of bagging at various stages of fruit development on calcium concentration and postharvest quality of ‘Kensington Pride’ mangoes. Fruits were bagged at 41, 25 or 9 days before harvest. No statistically significant differences in either skin or flesh calcium concentration were found between the bagged (plastic or paper) and unbagged fruits. Postharvest weight loss was enhanced and shelf life reduced in the ‘plastic bagged’ fruits. In an ancillary study, calcium concentrations in ‘Kensington Pride’ nubbins (seedless fruit) were compared with those in seeded fruit, since it has been shown with apple fruit that greater seededness is positively correlated with increased flesh calcium concentrations. Conversely, however, calcium concentrations in the flesh of mango nubbins were found to be significantly higher (0.80 mg/g dry weight) than those in seeded fruit (0.58 mg/g dry weight) of similar size.

Sub-zero temperatures can result in freezing injury of broccoli (Brassica oleracea L. var. italica Plenck) plants and thereby reduce head yield and quality. In order to predict effects of frosts, it is desirable to know the stages of development at which broccoli plants are most susceptible to freezing injury. In this study, the effect of a range of sub-zero temperatures for a short period at different stages of crop development were assessed and quantified in terms of mortality, yield and quality of broccoli. Whole plants in pots or in the field were subjected to sub-zero temperature regimes from -1 to -19 degrees C. Extracellular ice formation was achieved by reducing temperatures slowly, at -2 degrees C per hour. The floral initiation stage was most sensitive to freezing injury, as yields (fresh and dry head weights) were significantly reduced at -1 and -3 degrees C, and the shoot apices were killed at -5 degrees C. There was no significant yield reduction when the inflorescence buttoning stage was treated at -1 and -3 degrees C. Although shoot apices survived the -5 degrees C treatment at buttoning, very poor quality heads of uneven bud size were produced as a result of arrested development. The lethal temperature for pot-grown broccoli was between -3 and -5 degrees C, whereas the lethal temperature for field-grown broccoli was between -7 and -9 degrees C. The difference was presumably due to variation in cold acclimation. Freezing injury can reduce broccoli head yield and quality and retard plant growth. With regard to yield and maturity prediction, crop development models based only on simple thermal time without restrictions will not apply if broccoli crops are frost damaged.

Pyrimethanil (Scala) is a fungicide that might be used for control of Botrytis cinerea infecting Geraldton waxflower. New treatments are sought to reduce the risk of developing strains of B. cinerea that are resistant to fungicides commonly used against it, such as benomyl (Benlate) or iprodione (Rovral). Scala was applied to waxflower as a postharvest dip at 1.5 or 2 mL product/L. Disease severity on and flower and leaf drop from waxflower bunches pre-inoculated with B. cinerea were significantly (P = 0.05) reduced by treatment with Scala. Further, flower and foliage vase lives were significantly (P = 0.05) longer as a result of postharvest treatment with Scala as compared with water-treated (control) stems. Similar degrees of disease control where achieved with either Scala or Rovral. The results demonstrate that Scala has real potential as an alternative fungicide for control of B. cinerea on waxflower.

Summary. The large and colourful cut inflorescences of the terminal flowering tropical Grevillea species and hybrids are considered by enthusiasts to have potential as a cutflower crop. Developing understanding of the characteristics of grevillea inflorescences is collated in this review article. Botany, quality, cultivars, production and marketing, physiology and biochemistry, growth and development, flowering regulation, senescence, postharvest losses, pests and diseases, loss reduction measures, and use of floral preservatives for cut inflorescences are discussed. This overview of current knowledge provides a platform for future research and development on this novel native Australian flower.

Summary.‘Kensington’ mango fruit harvested at the mature green stage were partial pressure (vacuum) infiltrated with calcium (4 g Ca 2+/L as CaCl2) at 3 reduced pressure levels (–33, –66 and –99 kPa). Concentrations of Ca2+ in unripened calcium-treated fruit were about 1-, 2- and 3-fold higher, respectively, than Ca2+ concentrations in the skin and flesh of control (untreated; i.e. not vacuum infiltrated) fruit. For example, skin tissue Ca2+ concentrations of control fruit and of those treated at –33, –66 and –99 kPa were 1.51, 1.93, 3.42 and 5.01 mg Ca2+/g dry weight, respectively. Concentrations of Ca2+ in the skin of both control fruit and of Ca2+ -treated fruit were consistently higher, by about 2-fold, than those in the fruit flesh. Compared with the –33 kPa infiltration treatment, Ca2+ levels in the fruit flesh were increased by only about 2-fold by further reductions in the partial pressure infiltration levels to –66 or –99 kPa. Infiltration of Ca2+ into mango fruit was apparently via lenticels and along xylem conduits open at the cut pedicel. These infiltration pathways were revealed by inclusion of Brilliant Blue dye in the Ca2+ solution. Undyed and dyed lenticels were separately excised for Ca2+ analysis. Dark (dyed) lenticels had higher Ca2+ concentrations (1.86 ± 0.11 mg Ca2+/g dry weight) than light (undyed) lenticels (0.83 ± 0.19 mg Ca2+/g dry weight). Partial pressure infiltration of Ca2+ at any of the 3 subatmospheric pressure levels did not result in shelf life extension. Fruit infiltrated at –66 and –99 kPa exhibited injuries, which included exacerbated lenticel blackening and anaerobic off-odour and taste evident at the end of shelf life. In comparison, both control (untreated) mango fruit and those infiltrated with Ca2+ at –33 kPa ripened normally.

Summary. Devices which offer simple, inexpensive, reliable and non-destructive objective measurement of fruit firmness assist in the monitoring of quality. For the present study, the Analogue CSIRO Tomato Firmness Meter (AFM), which measures fruit deformation under a 500 g load applied for 30 s was modified by replacing the analogue displacement gauge with a digital gauge and by using a laboratory jack for positioning the fruit in the vertical dimension. Non-destructive measurements of tomato fruit softening during ripening and determined with the Digital Firmness Meter (DFM) were strongly correlated with both firmness measured with the AFM (r2 = 0.96, n = 19) and with firmness determined subjectively by hand pressure (r2 = 0.93, n = 19). Similarly, mango fruit softening during ripening was monitored and DFM and hand firmness measurements were well correlated (r2 = 0.95, n = 10). The firmness of individual fruit could be measured around 20% faster with the DFM than with the AFM, and displacement was easier to read from the digital than from the analogue display. The DFM proved to be a suitable device for measuring fruit firmness in postharvest laboratory studies and warrants evaluation under commercial packing and handling conditions.

Summary. Short vase life (e.g. 3–7 days) is a problem with inflorescences of Grevillea used as cut flowers and may be associated with depletion of respirable substrates. A series of 4 experiments addressing this hypothesis were conducted with Grevillea hybrid ‘Sylvia’ inflorescences. In experiment 1, the effect of leaf retention on inflorescence stems and a range of sucrose concentrations (0–6% w/v) in vase solutions was investigated. In experiment 2, the relationship between inflorescence maturity (4 stages) and sucrose supply was studied. In experiment 3, the effect of sucrose concentration as a short period pulse and pulsing duration was determined. In experiment 4, simulated handling and transport was undertaken to gauge the practical usefulness of sucrose pulsing to the cut flower industry. These vase life experiments were conducted in a constant temperature room (22 ± 2°C) at 50–80% relative humidity. All vase solutions contained 10 mg chlorine/L to suppress microbial growth. Three percent sucrose (w/v) was found in experiment 1 to be the best vase solution. This treatment gave a mean vase life of 10.1 ± 0.2 days, which was 44% longer than the control (no sucrose) treatment. Inflorescences picked at the ‘early looping’ stage and provided with 3% (w/v) sucrose had the best overall vase life (12.0 ± 0 days) and visual appeal in experiment 2. Sucrose pulsing (10% w/v) for 6–24 h extended vase life by at least 1 day. The presence of leaves shortened the vase life of both sucrose-pulsed and non-pulsed inflorescences by about 1 day in experiment 3. Storage for 5 days at 5°C as handling/transport simulation in experiment 4 did not shorten the vase life of Grevillea ‘Sylvia’ inflorescences. Sucrose pulsing (10% w/v) before simulated handling/transport did not result in a significant increase in the vase life of Grevillea ‘Sylvia’ inflorescences, and is therefore not recommended. To achieve the best floral display, Grevillea ‘Sylvia’ inflorescences should be picked at the ‘early looping’ stage of maturity and then placed in a vase solution containing 3% (w/v) sucrose.

Summary. Flowering sprigs of Geraldton waxflower (Chamelaucium uncinatum Schauer cv. ‘Alba’) inoculated with Botrytis cinerea, Alternaria alternata or left uninoculated (control treatment) were kept in sealed plastic containers (model packages). Three relative humidity treatments (75, 90 or 100%) by 4 temperature treatments [5, 10, 20 or 5/20° C (alternated daily)] were maintained. An additional treatment of ethylene absorbent (Purafil) sachets in the model packages was included. Disease severity, flower fall and desiccation were monitored over 22 days. Both disease severity and flower fall were reduced in treatments with no inoculum, at lower temperatures (5, 10 and 5/20°C) and under reduced relative humidities (75 and 90%). However, desiccation was a problem at 75 and 90% relative humidity and at 20 and 5/20°C. Ethylene scrubbing at 100% relative humidity did not significantly reduce disease severity or flower fall. Considered collectively, our results show that postharvest disease severity, flower fall and desiccation can be minimised by keeping waxflower at ≤10˚C and ≥90% relative humidity.

Summary. Water loss and premature ripening during postharvest handling reduce the market quality of mango fruit. Towards investigating the use of moisture barrier liners for mango fruit trays, relationships between in-package relative humidity and weight loss and ripening of ‘Kensington Pride’ fruit were studied. Individual fruit were held at 20°C in sealed plastic containers (small 1.2 L buckets). The lid of each container had a single circular hole. Holes were of various sizes, ranging from 5 to 135 mm diameter. Ripening mature green fruit held at the lowest relative humidity of 57% (135 mm diameter hole) lost weight at a significantly (P£0.05) greater rate (10 mg/g initial FW. day) than fruit at higher relative humidities of 59 (open air), 60 (95 mm diameter hole), 61 (55 mm diameter hole), 71 (35 mm diameter hole), 74 (25 mm diameter hole) and 83% (25 mm diameter hole plus free water). These fruit at higher relative humidities lost weight at rates ranging between 9 and 4 mg/g initial FW. day. Fruit softening and skin colouring rates were similar across all relative humidities. In a second experiment, mango fruit were allowed to ripen in containers with smaller holes, ranging from 5 to 95 mm diameter, in their lids. Fruit at the lowest relative humidity (60%, 95 mm diameter hole) lost weight at a significantly (P≤0.05) greater rate (9 mg/g initial FW. day) than fruit from other treatments. Furthermore, these fruit ripened about 2 days sooner than fruit at higher relative humidities: 85 (25 mm diameter hole), 88 (15 mm diameter hole), 91 (10 mm diameter hole) and 93% (5 mm diameter hole). Fruit at the higher relative humidities lost weight at rates between 6 and 2 mg/g initial FW. day, and ripened in 6 to 12 days. Thus, hole size can be varied in order to control in-package relative humidity and regulate mango fruit weight loss and ripening. Australian Journal of Experimental Agriculture, 1997, 37, 463–7 463

Mango fruit may be bagged during their development on the tree in order to reduce disease incidence and skin blemish. However, the influence of fruit bagging on calcium accumulation and their storage and ripening characteristics has not been reported. ‘Sensation’ mango fruit were bagged with commercially available plastic or paper bags 7 weeks before normal harvest. No significant differences in calcium concentrations between bagged (plastic or paper) and unbagged fruit were recorded for either skin or flesh tissue. Plastic bags resulted in increased fruit water (weight) loss after harvest. Softening and colouring of fruit which had been bagged with plastic were both hastened. Paper bags had no apparent influence, compared with unbagged control fruit, on weight loss or ripening characteristics of ‘Sensation’ mango fruit.

In postharvest dipping treatment of Geraldton waxflower (Chamelaucium uncinatum), 13 insecticides tested at recommended application rates caused no visual injury, but some reduced vase life. Flowers of cv. Purple Pride were more sensitive to insecticides than leaves. There was no loss of vase life of flowers following dipping in chlorpyrifos, dimethoate or permethrin. Following dipping in deltamethrin, carbaryl, dichlorvos, cypermethrin, endosulfan or fenvalerate there was 31-49% loss of vase life. No loss of vase life was observed for cv. Alba, after dipping in carbaryl, fenvalerate or dimethoate. Insecticide dips containing wetting agent and a fungicide (e.g. a combination of deltamenthrin, Aqua and benomyl) was a suitable dip for Geraldton waxflower. Wetting agents varied in their effect on vase life. Aqua shortened vase life less than Agral, and D-CTrate less than D-C-Tron. Stems rapidly lost weight when held out of water following dipping, and vase life was reduced when ambient temperatures were above 30�C or drying times exceeded 60 min. It was concluded that flowers should be kept cool and well hydrated following dipping treatment.

The performance of 7 commercial zinc (Zn) foliar nutrients sprays, based on sulfate (Top ZM), hydrated sulfate (Pivot Zinsol; Pivot Mangasol-zinc), oxide (Phosyn Zintrac), and ligninsulfonate (Spray-gro Zn PC; Spray-gro Zn/Mn PC; SJB), were assessed with and without addition of a horticultural petroleum spray oil (PSO), Ampol D-C-Tron NR. Foliar Zn deposition and absorption was quantified by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) after solvent washing and acid extraction. Effects on photosystem II were measured by chlorophyll fluorescence. Although none of the Zn sprays were soluble in PSO, all but Zn oxide could be suspended adequately before spraying. A partial emulsion break occurred with Zn sulfate and hydrated sulfates. All treatments increased the Zn content of leaves by an amount likely to alleviate Zn deficiency. Addition of PSO decreased deposition and absorption of Zn when used with the inorganic formulations or with Spray-gro Zn PC. Zinc deposition and absorption were increased by PSO in Spray-gro Zn/Mn PC, and were unaffected by PSO in SJB. Plant chlorophyll fluorescence and phosphorus content did not differ among treatments. The ligninsulfonates Spray-gro Zn/Mn PC and SJB were most compatible with Ampol D-C-Tron NR, and had relatively low potential for Zn pollution of the environment.

Mycelial growth in vitro of 2 fungal pathogens responsible for postharvest loss of horticulture produce, Botrytis cinerea and Alternaria alternata, was related to equilibrium relative humidity (e.r.h) at ambient temperature (20�C) using solutes to adjust the 'osmotic water potential' of the growth medium. Colony diameter growth of B. cinerea and A. alternata on solid medium (1/2 potato dextrose agar) was initially stimulated slightly when the e.r.h. was decreased from 99.7 (unamended medium) to 99.3% (-0.4 to -1.0 MPa). Thereafter, colony diameter growth continually decreased as a function of reducing e.r.h. over the range 99.3-94.3% e.r.h. (-1.0 to -8.0 MPa). Similar trends were recorded with both pathogens for their dry matter growth in liquid medium (Oxoid Czapek Dox) as a function of osmotic potential. Initial stimulation of dry matter growth at -1.0 MPa (equivalent to 99.3% e.r.h.) was not evident in liquid medium. Fungal growth data suggest that postharvest mycelial growth of Botrytis cinerea and Alternaria alternata on wounds, senescing tissue or secretions such as cell sap or nectar could be restricted through control of e.r.h. in packages of horticulture produce.

Grevillea is a large genus containing many species, forms and hybrids bearing inflorescences with desirable cut flower characteristics. Nineteen different Grevillea spp. and forms (7), and 39 hybrids (including 11 repeat collections) were assessed for vase life. Longevity varied 3-fold, from 3 days for G. wickhamii to 9 days for a G. whiteana accession. Species with comparatively long vase lives included G. pteridifolia, G. sessilis and G. whiteana. These genotypes may be useful for cut flower production and/or in breeding programs aimed at producing new cut flower Grevillea.

A triazole compound, triadimenol, and metluidide were evaluated as vase solution ingredients for Geraldton waxflower. It was anticipated, on the basis of published literature, that these chemicals might induce endogenous abscisic acid (ABA) accumulation and associated stomatal closure, thereby providing an improved water balance. Triadimenol (10 mg/L) generally extended both foliage and flower vase life for the 3 cultivars of Geraldton waxflower studied. However, the increased longevity was associated with greater, rather than less, vase solution usage. Therefore, stomatal closure was not induced, and the beneficial effect was evidently not a function of significantly increased endogenous ABA levels. Mefluidide did not extend the vase life of Geraldton waxflower.

Film wrapping and waxing are both known to extend the shelf life of harvested avocado fruit. However, the effect of delays in film wrapping and waxing on shelf life has not been reported. Early, mid, and late season avocado cv. Hass fruit were wrapped in 'Glad Wrap' or waxed in 'Avocado and Passion-fruit Wax' at intervals of up to 96 h after harvest. Compared with untreated control fruit, both wrapping and waxing delayed softening and colour change at 22�C by about 50%. Loss in fruit weight during ripening was reduced more by wrapping than by waxing. Delaying wrapping or waxing by up to 48 h after harvest was not associated with consistent differences in shelf life. There was, however, significant (P

Changes in leaf angle and flower diameter of Geraldton wax (Chamelaucium uncinatum) in response to declining shoot water potential (ψshoot)) were assessed as indicators of plant water status. Leaves and petals in Geraldton wax moved vertically as ψshoot decreased. In cv. Purple Pride, the leaf angle of recently-matured, fully-expanded leaves and the diameter of fully developed flowers showed strong linear correlations with declining ψshoot (r2 = 0.90 and 0.94 respectively). The relationships were less strong when applied to almost fully expanded leaves (r2 = 0.51) and young flowers (r2 = 0.64). Older leaves showed no consistent correlation between leaf angle and ψshoot (r2 = 0.01). Similar results were observed in cvv. Alba and Lady Stephanie, but the change in orientation for a given change in ψshoot was smaller in cv. Alba than those observed in cvv. Purple Pride and Lady Stephanie. Vertical orientation of leaves and flower petals in droughted plants could be used as indicators of level of water deficit.

An ethylene permeation system was tested in a study of flower abscission of Verticordia nitens (Lindley) Endl. Various concentrations of ethylene in air were generated by passing air, at a flow rate of 2 L/min, through chambers containing various lengths of polyvinyl chloride (PVC) tubing pressurised (50 kPa) with ethylene. Ethylene permeating through lengths of PVC tubing of 1.5, 15, 150, and 1500 cm (8 mm internal diameter, 1.5 mm wall thickness) gave ethylene concentrations in the outflow airstreams of 0.12, 0.99, 7.8, and 100 �L/L, respectively. Increasing the ethylene pressure in 150-cm-long tubing linearly increased the permeation of ethylene (0.07 �L/L. kPa). A log-linear abscission response of V. nitens flowers to increasing ethylene concentration was demonstrated using this system. Use of silicone tubing (8-mm internal diameter, 1.5-mm wall thickness) resulted in an ethylene flux 75 times that of the same length of PVC tubing. Higher flux through silicone tubing should allow development of ethylene permeation gassing systems suitable for use in fruit ripening and degreening rooms.

Possible reasons for, and prevention of, postharvest floral organ fall in Geraldton waxflower (Chamelaucium unciizatum Schauer) were studied. An 11-kg compression load, equivalent to the lidding of a carton, caused flower fall amounting to 1% of the fresh mass of 420-g bunches. Fungal development also resulted in flower abscission. Healthy flowers produced little ethylene (e.g. 0.05 �L/kg.h), while infected flowers produced much more (e.g. 7.71 �L/kg.h) and were shed. Treatment with fungicide (iprodione + mancozeb) and antiethylene compounds [e.g. silver thiosulfate (STS) pulse, Purafil sorbant] reduced flowerfall in packaged flowers. Cut sprigs which suffered severe water deficit also shed flowers. In cv. Elegance, drying to -3.61 MPa elevated ethylene production (e.g. 1.35 �L/kg . h). Flowerfall induced by water deficit could be reduced by pretreatment with a STS pulse (0.5 mmol Ag+/L for 15-22 h at 0�C or 4 mmol Ag+/L for 20-30 min at about 20�C). Pretreatment with a naphthaleneacetic acid dip (50 mg/L for 1 min at room temperature) shortened the vase life of Elegance.

The starch distribution pattern and decline in starch content of Sonia rose petals were examined by starch-iodine staining. Flowers were harvested and held in 150 mg/L of sodium dichloroisocyanurate (DICA) or 150 mg DICA/L + 2% (w/v) sucrose, or were left on the plant. Starch was degraded initially from the outer margins of petals, then from the interveinal area nearest the petal margins, and finally towards the petal bases. Starch was first lost from the outermost petal and then sequentially towards the innermost petals. The rate of starch degradation was slowest in flowers left on the plant, intermediate in flowers harvested and kept in DICA + sucrose, and most rapid in flowers harvested and held in DICA. Preharvest treatments applied in an attempt to vary starch deposition (i.e. shading, leaf removal, and leaf removal with girdling) did not alter the normal starch-iodine staining pattern, reduce starch concentrations, or reduce vase life. However, flower pigmentation was less intense, abnormal flower development occurred, and dry weight and starch contents were reduced, suggesting that carbohydrate supply to the developing bud was affected. Thus, starch-iodine staining of cleared petals of mature Sonia roses was not useful for identifying flowers that developed under conditions of restricted carbon supply. In petals of flowers that had been harvested and held in cool storage (0-3�C) for 7 days, starch was degraded evenly from all parts across the petal. This diffuse pattern of starch degradation was sufficiently distinctive that it may prove a useful test for determining whether flowers have been cool-stored.

The potential for ethylene-induced abscission among Verticordia species used for cut flowers (V. nitens, V. chrysantha, V. plumosa, and V. densiflora) was studied by treating them with 2-chloroethyl-phosphonic acid (ethephon) or exposing them to dilute ethylene gas. The possibility that ethylene production induced by water stress may cause flower abscission was also investigated. Dipping in ethephon (500 or 1000 mg/L) failed to induce flower abscission in V chrysantha or V plumosa. Treatment with ethylene (8.6 pL/L) failed to induce flower abscission in V. densiflora. Ethephon and ethylene both induced substantial flower, pedicel, and leaf abscission in V. nitens. Pretreatment with silver thiosulfate prevented ethylene-induced flower abscission in V nitens. Dehydrating stems for periods of 6, 12, 24, or 48 h at about 20�C did not induce flower abscission in either V plunzosa or V nitens. Dehydration periods of 6 and 12 h had no effect on longevity. Longer drying periods (24 and 48 h) induced early loss in appearance (visual quality) of both species.

The Australian dried flower and foliage industry is expanding rapidly because of increasing demand overseas for unique native flora. The industry compliments the export of fresh, native cut flowers. Bleaching is an important step in the processing of plant material that is to be marketed, bleached or dyed. Profitability is dependant upon attainment of high white quality and on cost efficient utilisation of expensive bleaching chemicals. Sodium chlorite is an excellent bleaching agent because it is relatively selective for lignin. Hydrogen peroxide may be more practical for some plant materials because it is less expensive. Choice of an effective bleach activator, such as hypochlorous acid for chlorite bleach, is critical for cost efficient processing. Relative efficiency of different bleach regimes can be compared by assaying residual lignin using ultraviolet or fourier transform infrared spectroscopy. Multistage bleaching, where peroxide is used first to remove about 50% of lignin, followed by chlorite treatment, is likely to reduce processing costs.