ORCID Profile
0000-0002-6992-9155
Current Organisations
University of the Sunshine Coast
,
University of Queensland
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Publisher: Wiley
Date: 10-1998
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.PLAPHY.2015.11.012
Abstract: Breadfruit (Artocarpus altilis) is a traditional staple tree crop in the Oceania. Susceptibility to windstorm damage is a primary constraint on breadfruit cultivation. Significant tree loss due to intense tropical windstorm in the past decades has driven a widespread interest in developing breadfruit with dwarf stature. Gibberellin (GA) is one of the most important determinants of plant height. GA 2-oxidase is a key enzyme regulating the flux of GA through deactivating biologically active GAs in plants. As a first step toward understanding the molecular mechanism of growth regulation in the species, we isolated a cohort of four full-length GA2-oxidase cDNAs, AaGA2ox1- AaGA2ox4 from breadfruit. Sequence analysis indicated the deduced proteins encoded by these AaGA2oxs clustered together under the C19 GA2ox group. Transcripts of AaGA2ox1, AaGA2ox2 and AaGA2ox3 were detected in all plant organs, but exhibited highest level in source leaves and stems. In contrast, transcript of AaGA2ox4 was predominantly expressed in roots and flowers, and displayed very low expression in leaves and stems. AaGA2ox1, AaGA2ox2 and AaGA2ox3, but not AaGA2ox4 were subjected to GA feedback regulation where application of exogenous GA3 or gibberellin biosynthesis inhibitor, paclobutrazol was shown to manipulate the first internode elongation of breadfruit. Treatments of drought or high salinity increased the expression of AaGA2ox1, AaGA2ox2 and AaGA2ox4. But AaGA2ox3 was down-regulated under salt stress. The function of AaGA2oxs is discussed with particular reference to their role in stem elongation and involvement in abiotic stress response in breadfruit.
Publisher: Inderscience Publishers
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 04-01-2014
DOI: 10.1007/S10863-013-9538-4
Abstract: Plasma membrane (PM) plays central role in triggering primary responses to chilling injury and sustaining cellular homeostasis. Characterising response of membrane lipids to low temperature can provide important information for identifying early causal factors contributing to chilling injury. To this end, PM lipid composition and ATPase activity were assessed in pineapple fruit (Ananas comosus) in relation to the effect of low temperature on the development of blackheart, a form of chilling injury. Chilling temperature at 10 °C induced blackheart development in concurrence with increase in electrolyte leakage. PM ATPase activity was decreased after 1 week at low temperature, followed by a further decrease after 2 weeks. The enzyme activity was not changed during 25 °C storage. Loss of total PM phospholipids was found during postharvest senescence, but more reduction was shown from storage at 10 °C. Phosphatidylcholine and phosphatidylethanolamine were the predominant PM phospholipid species. Low temperature increased the level of phosphatidic acid but decreased the level of phosphatidylinositol. Both phospholipid species were not changed during storage at 25 °C. Postharvest storage at both temperatures decreased the levels of C18:3 and C16:1, and increased level of C18:1. Low temperature decreased the level of C18:2 and increased the level of C14:0. Exogenous application of phosphatidic acid was found to inhibit the PM ATPase activity of pineapple fruit in vitro. Modification of membrane lipid composition and its effect on the functional property of plasma membrane at low temperature were discussed in correlation with their roles in blackheart development of pineapple fruit.
Publisher: MDPI AG
Date: 10-2020
DOI: 10.3390/HORTICULTURAE6040061
Abstract: The Kingdom of Tonga has one of the highest rates of diet-related non-communicable diseases (NCDs) in the world. Initiatives to promote pro-health dietary behaviour are possibly being compromised by poor or inconsistent consumer accessibility to affordable and safe fresh fruits and vegetables, referred to as the agriculture–nutrition–income nexus. While donors increasingly focus on nutrition-sensitive agriculture across the Pacific, there is little contemporary information concerning Tonga’s domestic horticultural distribution and market system, particularly in regards to food loss. This study surveyed 292 municipal and road-side vendors on Tongatapu and ‘Utu Vava’u Islands, with the aim of mapping and analyzing horticultural markets and farm supply, transport logistics, and quantifying postharvest practice and market loss. Tonga’s domestic horticultural market structure consists of a central municipal market and on Tongatapu Island, a supplementary network of urban and rural based road-side vendors. There is limited inter-island trade, with most farms located within 25 km of the central municipal market. Mean postharvest horticultural loss was very low, at 1.4% to 5.3%, with road-side vendors more vulnerable to loss. This level of loss was thought to reflect short intra-island transport distance, the type of crops being traded, and rapid market throughput, rather than a level of value chain efficiency. Vendors regulated market supply volume and price discounting and were the principal strategies to mitigate postharvest loss. While low levels of postharvest loss, short transport logistics, and fast market throughput are consistent with a relatively efficient horticulture market system, vendor practice may be impeding fresh fruit and vegetable accessibility.
Publisher: Informa UK Limited
Date: 13-03-2017
Publisher: Informa UK Limited
Date: 04-2020
Publisher: Elsevier BV
Date: 07-1993
Publisher: International Society for Horticultural Science (ISHS)
Date: 11-2013
Publisher: International Society for Horticultural Science (ISHS)
Date: 04-2002
Publisher: International Society for Horticultural Science (ISHS)
Date: 04-2002
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/EA97092
Abstract: Summary. ‘Eureka’ and ‘Lisbon’ lemons (Citrus limon L.) from the Burnett region in Queensland were stored for 14, 28 or 42 days at 1˚C followed by 7 days at 20˚C to compare their relative susceptibility to chilling injury. The potential effect of cultivar on injury development was examined by harvesting fruit from trees subjected to the same growing conditions to minimise all other variability. Injury appeared in both cultivars after storage at 1˚C for 14 days and 7 days at 20˚C. The incidence of commercially unacceptable chilling injury (moderate and severe) was significantly higher in Lisbon than Eureka fruit after all storage treatments, except for 42 days at 1˚C plus 7 days at20˚C. Eureka and Lisbon lemons had similar respiration rates at 20˚C, but respiration of Lisbon following storage at 1˚C for 14, 28 and 42 days was significantly higher than that of Eureka. Storage at 1˚C for 14 days resulted in elevated respiration in both cultivars, with a peak occurring during the first 24 h. After 28 days at 1˚C, peak respiration increased to 51 mg/kg.h for Lisbon and 34 mg/kg.h for Eureka lemons. Respiration increased significantly with longer storage periods, consistent with extensive chilling injury. It is suggested that the lack of commercial success of cold-treated Queensland-grown Eureka lemons is not because they are more sensitive to chilling injury than Lisbon lemons.
Publisher: MDPI AG
Date: 07-10-2022
DOI: 10.3390/HORTICULTURAE8100916
Abstract: Breadfruit (Artocarpus altilis) is a traditional fruit tree of 15–30 m tall in Oceania. The species is a staple crop for food security in the tropics. Tree loss from tropical windstorms, together with transition toward high-density planting has driven an interest in the dwarf phenotype of the species. Information on dwarfing rootstocks for breadfruit is currently limited. The aim of this study was to assess the performance of breadfruit growth with lakoocha (Artocarpus lakoocha) as rootstocks. We compared the phenotype of breadfruit trees on lakoocha rootstocks with those on self-graft and non-graft within 21 months after grafting. These led to the discovery of a rootstock-induced dwarf trait in breadfruit species. Breadfruit scions on lakoocha rootstocks displayed a reduction in tree height, stem thickness, and internode length, with fewer branches and leaves, resulting in about 32% of the standard height at the end of 21 months after grafting. These suggest lakoocha rootstocks have the potential to control breadfruit tree vigor. Non-structural carbohydrate analysis showed the composite trees exhibited lower hexose concentration in both scion stems and roots, but higher sucrose level in scion stems, and higher starch level in roots. The significance of these parameters in rootstock dwarfing is discussed.
Publisher: International Society for Horticultural Science (ISHS)
Date: 07-2016
Publisher: International Society for Horticultural Science (ISHS)
Date: 11-2016
Publisher: Elsevier BV
Date: 07-1999
Publisher: MDPI AG
Date: 16-09-2023
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/EA9940115
Abstract: Mature red lychee fruit were stored at 3 different temperature and relative humidity regimes. Total anthocyanin concentration, pigment distribution, pH of the pericarp homogenate, Hunter a values (redness index), and visual colour were measured as a function of pericarp weight loss. Pericarp colour rapidly deteriorated during both ambient and high temperature storage, resulting in a uniform browning of the pericarp surface. The degree of tissue browning was proportional to the rate of pericarp desiccation. Although anthocyanin degradation occurred concurrently with tissue browning, visual colour and Hunter a values were not consistent with total anthocyanin concentration. Instead, a more significant correlation was seen between Hunter a values and the pH of the pericarp homogenate. Pericarp colour could be altered by external pH. Acidification of whole fruit increased pericarp redness, whereas alkaline treatment caused discoloration. Both colour responses occurred independently of anthocyanin synthesis and degradation and were completely reversible. These results question the current theory that browning is due to anthocyanin degradation. No evidence of browning was observed in the anthocyanin-containing mesocarp, and acidification of already brown tissue significantly increased pericarp redness independently of anthocyanin synthesis. We believe that anthocyanin pigments were progressively decolorised during ambient storage, possibly due to changes in pericarp pH. Once colourless, independent tissue browning became visual and was enhanced.
Publisher: CSIRO Publishing
Date: 1997
DOI: 10.1071/EA96051
Abstract: Summary. Prestorage heat treatments at 47–53°C for 1–3 min were investigated as a potential control of chilling injury in cold disinfested ‘Eureka’ lemons (Citrus limon). Hot water dips significantly reduced the incidence of chilling injury in fruit stored at 1°C for 28 and 42 days. Storage at 1°C for 14 days resulted in comparatively minor chilling injury, so that hot water dips gave little additional benefit. This result is thought to reflect the low incidence of chilling injury, rather than the lack of effectiveness of heat treatments. Scald damage (surface browning) occurred after 3 min at 53°C. Heat treatments had no significant effect on the incidence of disease at all durations of storage. The rate of fruit weight loss during 7 days at 20°C after storage for 14, 28 or 42 days at 1°C was significantly lower in heat- treated fruit.
Publisher: Wiley
Date: 30-08-2018
DOI: 10.1111/PLB.12879
Abstract: Breadfruit (Artocarpus altilis) is primarily grown as a staple tree crop for food security in Oceania. Significant wind damage has driven interest in developing its dwarfing rootstocks. Due to the predominantly vegetative propagation of the species, grafting onto interspecific seedlings is an approach to identifying dwarfing rootstocks. However, grafting of breadfruit onto unrelated Artocarpus species has not been investigated. Here we first report the success of breadfruit grafting onto interspecific rootstocks, marang (A. odoratissimus) and pedalai (A. sericicarpus). To address the low graft survival, we investigated the relationship of plasma membrane (PM) H
Publisher: International Society for Horticultural Science (ISHS)
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 31-07-2015
Publisher: MDPI AG
Date: 15-05-2020
Abstract: Breadfruit (Artocarpus altilis) is a traditional staple tree crop throughout the tropics. The species is an evergreen tree 15–20 m there are currently no size-controlling rootstocks within the species. Through interspecific grafting, a dwarf phenotype was identified in breadfruit plants growing on Marang (Artocarpus odoratissimus) rootstocks, which displayed ~60% reduction in plant height with ~80% shorter internodes. To gain insight into the molecular mechanism underlying rootstock-induced dwarfing, we investigated the involvement of gibberellin (GA) in reduction of stem elongation. Expression of GA metabolism genes was analysed in the period from 18 to 24 months after grafting. In comparison to self-graft and non-graft, scion stems on marang rootstocks displayed decrease in expression of a GA biosynthetic gene, AaGA20ox3, and increase in expression of a GA catabolic genes, AaGA2ox1, in the tested 6-month period. Increased accumulation of DELLA proteins (GA-signalling repressors) was found in scion stems growing on marang rootstocks, together with an increased expression of a DELLA gene, AaDELLA1. Exogenous GA treatment was able to restore the stem elongation rate and the internode length of scions growing on marang rootstocks. The possibility that GA deficiency forms a component of the mechanism underlying rootstock-induced breadfruit dwarfing is discussed.
Publisher: Springer Science and Business Media LLC
Date: 22-03-2014
DOI: 10.1007/S00232-014-9650-3
Abstract: Vacuole represents a major storage organelle playing vital roles in pH homoeostasis and cellular detoxification. The chemical and functional properties of tonoplast in response to chilling temperature and their roles in chilling injury are largely unknown. In the current study, lipid composition of tonoplast and the activities of two vacuolar proton pumps, H?-ATPase (V-ATPase) and H?-pyrophosphatase (V-PPase), were investigated in accordance with the development of blackheart, a form of chilling injury in pineapple fruit (Ananas comosus). Chilling temperature at 10 °C for 1 week induced irreversible blackheart injury in concurrence with a substantial decrease in V-ATPase activity. By contrast, the activity was increased after 1 week at 25 °C. The activity of V-PPase was not changed under both temperatures. Level of total phospholipids of tonoplast decreased at 10 °C, but increased at 25 °C. There was no change at the level of total glycolipids under both temperatures. Thus, low temperature increased the ratio of total glycolipids vs. total phospholipids of tonoplast. Phosphatidylcholine and phosphatidylethanolamine were the predominant phospholipids of tonoplast. Low temperature increased the relative level of phosphatidic acid but decreased the percentage of both phosphatidylcholine and phosphatidylethanolamine. Unsaturated fatty acids accounted for over 60 % of the total tonoplast fatty acids, with C18:1 and C18:2 being predominant. Low temperature significantly decreased the percentage of C18:3. Modification of membrane lipid composition and its effect on the functional property of tonoplast at low temperature were discussed in correlation with their roles in the development of chilling injury in pineapple fruit.
Publisher: Springer Science and Business Media LLC
Date: 03-03-2023
DOI: 10.1186/S40066-023-00406-8
Abstract: When the global COVID-19 pandemic and state of emergency was declared in early 2020, South Pacific Island nations rapidly closed their borders resulting in significant socio-economic upheaval. With the South Pacific region highly vulnerable to external shocks, there was concern amongst Pacific governments and international donors as to the implications of COVID-19 restrictions on the local food system. Horticultural farmers and market vendors ( n = 825) were surveyed in Fiji, Tonga, and Samoa, using local enumerators, over a five-month period (July to November 2020), which represented the initial phase of COVID-19 restrictions in the region. Data were disaggregated based on location, farmer and vendor impacts, and postharvest loss. Farmers in Fiji (86%) were more likely to experience difficulties in selling their crops during the initial stages of COVID-19 restrictions, compared to farmers on the smaller Pacific Island nations of Tonga (10%) or Samoa (53%). While market vendors in Fiji (73.2%) and Tonga (56.8%) were similarly impacted, few vendors (22%) in Samoa were affected. Farmers and market vendors on the islands of Viti Levu (Fiji) and Upolu (Samoa), specifically those supplying or located in the key urban centres were more likely to experience elevated postharvest loss. Elevated postharvest loss due to COVID-19 was more prevalent amongst municipal market vendors, peri-urban farms and vendors sourcing from larger commercial farms. Road-side vendors and vendors in the rural areas were less likely to incur elevated loss. While fresh horticultural food systems in Fiji, Tonga, and Samoa were all adversely effected by COVID-19 restrictions, these impacts were more acute in Fiji. Given value chains associated with main urban centres were more likely to incur elevated postharvest loss, this would imply consumers were avoiding town centres and alternatively sourcing fresh fruit and vegetable from rural road-side vendors. Pacific road-side vendors appear to have provided an important fresh food distribution capacity during local COVID-19 travel restrictions.
Publisher: Springer Science and Business Media LLC
Date: 27-11-2017
Publisher: Informa UK Limited
Date: 22-10-2016
Publisher: Elsevier BV
Date: 04-2003
Publisher: Springer Science and Business Media LLC
Date: 21-07-2017
Publisher: International Society for Horticultural Science (ISHS)
Date: 12-2011
Publisher: MDPI AG
Date: 17-07-2019
DOI: 10.3390/NU11071622
Abstract: Ongoing dietary transitions in the Solomon Islands has resulted in an over-reliance on commercially sourced foods, leading to food insecurity, and a subsequent rise in multiple forms of malnutrition. The aim of this study was to investigate the in idual dietary ersity and food preferences of the adult population living in Auki, Solomon Islands. A cross-sectional study involving 133 adults was undertaken in the Auki district via an interviewer-administered questionnaire. In idual dietary ersity scores (DDS) were determined based on the results of a 24-h recall method. Overall mean DDS was 7.27 (range 2–12). Females and participants who lived outside the Auki town center had significantly higher dietary ersity scores. Low consumption of a variety of nutritious foods within food groups and high consumption of energy dense processed foods, indicates that diet quality is likely limited in some of this population. Participants desire for a erse diet including local foods suggests that current dietary ersity status in this population may be influenced by food security rather than food preference.
Publisher: MDPI AG
Date: 10-01-2019
DOI: 10.3390/HORTICULTURAE5010005
Abstract: Honiara’s fresh horticultural markets are a critical component of the food distribution system in Guadalcanal, Solomon Islands. Most of the population that reside in Honiara are now dependent on the municipal horticultural market and a network of smaller road-side markets to source their fresh fruits and vegetables. Potentially poor postharvest supply chain practice could be leading to high levels of postharvest loss in Honiara markets, undermining domestic food security. This study reports on a preliminary assessment of postharvest horticultural market loss and associated supply chain logistics at the Honiara municipal market and five road-side markets on Guadalcanal Island. Using vendor recall to quantify loss, we surveyed a total of 198 vendors between November 2017 and March 2018. We found that postharvest loss in the Honiara municipal market was 7.9 to 9.5%, and that road-side markets incurred 2.6 to 7.0% loss. Based on mean postharvest market loss and the incidence of in idual vendor loss, Honiara’s road-side market system appears to be more effective in managing postharvest loss, compared to the municipal market. Postharvest loss was poorly correlated to transport distance, possibly due to the inter-island and remote intra-island chains avoiding high-perishable crops. Spatial mapping of postharvest loss highlighted a cohort of villages in the western and southern parts of the main horticultural production region (i.e., eastern Guadalcanal) with atypically high levels of postharvest loss. The potential importance of market-operations, packaging type, and mode of transport on postharvest market loss, is further discussed.
Publisher: Informa UK Limited
Date: 02-11-2017
Publisher: Elsevier BV
Date: 02-1998
Publisher: CSIRO Publishing
Date: 1995
DOI: 10.1071/PP9950627
Abstract: Cellular localisation of visual browning and oxidative activity studies were conducted to determine the relative significance of polyphenol oxidase (PPO) and peroxidase (POD) activities during pericarp browning. Pericarp browning was first observed on the protuberance apices and subsequently extended uniformly over the entire pericarp surface. Anatomically, browning was highly localised and restricted to the epicarp and the upper mesocarp. PPO and POD activities were highest in the epicarp, with progressively less activity in both the mesocarp and endocarp. In situ localisation of oxidative activity using tissue blots confirmed high epicarp PPO activity. POD activity, although primarily restricted to mesocarp vascular tissue, was also detected in the epicarp. We believe that litchi pericarp browning is due to highly localised oxidative activity in the epicarp and upper mesocarp. As PPO and POD activities were significantly higher in this tissue and browning was not observed when both enzymes were selectively inhibited, it is postulated that both PPO and POD activities are associated with litchi pericarp browning. The current theory that litchi pericarp browning is only caused by PPO activity needs to be re-appraised to determine the relative role of POD activity.
Publisher: MDPI AG
Date: 11-2019
DOI: 10.3390/HORTICULTURAE5040074
Abstract: The Fiji Islands, like many small Pacific island nations, are thought to incur high rates of postharvest loss. Little work has been undertaken to quantify the amount of loss within Pacific horticultural value chains, or identify the key determinants. This study sought to quantify postharvest loss within Fijian smallholder tomato value chains and to examine the relative importance of current on-farm practices as possible contributors to this loss. A semi-structured survey of 115 smallholder tomato farmers in Sigatoka Valley and eastern Viti Levu was undertaken, covering socio-economic and demographic parameters, production and postharvest handling practice, and postharvest loss based on farmer recall. On-farm postharvest loss for smallholder farmer tomato value chains was between 26.1% in Sigatoka Valley and 27.6% in eastern Viti Levu. This finding was consistent with quantification of postharvest loss in Fijian tomato chains by direct determination, but is relatively high when compared to smallholder tomato value chain loss in Sub-Saharan Africa. When Fijian tomato value chains were segregated according to specific postharvest handling practice, the contributors to postharvest loss were often associated with on-farm decision-making. Those value chains that only harvested once a week, or in the early morning (before 7 am) or mid-day onwards, stored harvest product in the field for more than three hours, did not sort or grade prior to on-farm ripening, or used packing sheds that had relatively open designs, all had consistently higher levels of postharvest loss. The prevalence of specific postharvest handling practice in both locations is further reported. While this study highlights the impact of current on-farm postharvest handling practices on tomato value chain loss, what remain unclear are the underlying drivers associated with current postharvest handling behaviour and the decision-making that shapes quality and logistic control activities.
Publisher: MDPI AG
Date: 17-05-2019
DOI: 10.3390/HORTICULTURAE5020040
Abstract: Breadfruit (Artocarpus altilis) is a tropical fruit tree primarily grown as a staple crop for food security in Oceania. Significant wind damage has driven an interest in developing its dwarf phenotype. The presence of any dwarf breadfruit variety remains unknown. Little is known regarding the growth of the species on rootstocks. Here, we examined the phenotype of breadfruit plants growing on marang (Artocarpus odoratissimus) rootstocks within 18 months after grafting we identified a rootstock-induced dwarf trait in the species. This dwarf phenotype was characterized by shorter stems, reduced stem thickness and fewer branches, with 73% shorter internode length, 51% fewer and 40% smaller leaves compared to standard size breadfruit plants. The height of breadfruit plants on marang rootstocks was reduced by 49% in 9 months, and 59% in 18 months after grafting. The results suggest marang rootstocks can be applied to breadfruit breeding program for tree vigor control. Further biochemical characterization showed plants on marang rootstocks displayed leaves without change of total chlorophyll content, but with lower total soluble sugars, and stems with reduced activity of plasma membrane H+-ATPase, a well-known primary proton pump essential for nutrient transport. The significance of the two parameters in rootstock dwarfing is discussed.
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