Softening of apple fruit depends on maturity at harvest and a range of orchard and environmental factors. We investigated seasonal effects on 'Royal Gala' storage performance independent of maturity and separate from potential orchard effects. In two consecutive seasons, fruit were harvested at four times: very early (H1), early (H2), commercial (H3) and late (H4), and were cold-stored at 0.5 degrees C for 100 d followed by a shelf-life period. In Year 1, fruit from H1 and H2 softened much less during storage than did fruit from Year 2. Later-harvested fruit (H3 and H4) did not show this seasonal difference and softened similarly in storage. A combined at-harvest transcriptomic and metabolomic study was analysed using mixOmics. Retained firmness in storage was corre-lated with increased abundance of transcripts indicative of abiotic stress, including those encoding universal stress protein, a drought stress protein, and several heat shock proteins and aquaporins. Greater softening in storage was correlated with higher abundance of fewer and different stress genes, and genes involved in cell wall metabolism. The data suggest that preharvest stresses experienced by the fruit have a profound effect on sub-sequent softening, at least in early-harvested fruit before ripening-related ethylene becomes the main driver. Ten potential at-harvest biomarkers were identified, including titratable acidity, erythritol and eight transcripts (notably Universal stress protein PHOS32-like and Homeobox leucine zipper protein HAT5-like). These could be useful for predicting the subsequent storage performance of batches of fruit.

Accurate determination of kiwifruit maturity in the first half of the harvest window is crucial in predicting storage risk, since early-harvested fruit are more susceptible to disorders and rots during extended cold storage. Maturity estimations are usually based on soluble solids content (SSC), but SSC alone is unreliable at early harvest times, necessitating the need for more precise markers. To address this, we performed multi-omics on harvested, yellow-fleshed kiwifruit at four chronological ages based on days after anthesis, namely early harvest (H1), early-mid (H2), late-mid (H3) and late harvest (H4), across two seasons from the same orchard. Analysis of phenotype, transcriptome, metabolome, proteome, hormone concentrations and enzyme activity profiles identified discriminating features within the datasets that separated harvest times, particularly in the first half of the harvest window. Strong seasonal variability was observed. The most reliable variates for maturity estimation were found in the transcriptome, and two transcripts with sharply decreasing abundance during early harvest (Aquaporin TIP4-1 and MYB10) and three transcripts with sharply increasing abundance during later harvest (β-Amylase 3.2, Pectinesterase inhibitor protein and α-Terpineol synthase) with relative seasonal stability were identified. In a different season we used these five potential biomarkers in combination with SSC as a predictive tool. This allowed precise assessment of the maturity stage of fruit in the first half of the harvest window from 12 orchards in four geographical regions, and accurate prediction of their storage outcome.

Accurate assessment of apple fruit maturity at harvest is required since fruit harvested too early or too late are susceptible to physiological disorders or excessive softening during subsequent storage. Biological markers of early fruit maturity allow forecasting of optimal harvest time, contributing significant industry value through more accurate management of harvest logistics. This study investigated the changes in cortex of apple (Malus x domestica ‘Royal Gala’) fruit at four harvests: very early (H1), early (H2), commercial (H3) and late (H4), using a combination of transcriptomics, metabolomics, hormone abundances and enzyme activity profiles. Harvest times were discriminated based on several sets of variates, showing that metabolism was very active within this short time period. Good discrimination between H1 and H2 and between H2 and H3 was observed in the declining abundance of a range of photosystem transcripts and the increasing abundance of early ripening markers. Degradation of the photosynthetic apparatus was correlated with ethylene production. Multi-omics analysis using mixOmics identified groups of variates whose abundance declined or increased during the harvest period, and strong correlations between components of different pathways were evident. We identify a suite of biomarkers, including Chl a/b binding protein of LHCII, Xyloglucan glycosyltransferase 5, PG1, ACO1, internal ethylene concentration and starch pattern index, for orchardists to accurately predict harvest time several weeks in advance, thus providing time to mobilise the necessary logistical resources.

The benefits of lowering blood pressure (BP) are well established for the prevention of cardiovascular disease. While there are a number of pharmaceuticals available for lowering BP, there is considerable interest in using dietary modifications, lifestyle and behaviour changes as alternative strategies. Kukoamines, caffeic acid derivatives of polyamines present in solanaceous plants, have been reported to reduce BP. We investigated the effect of orally administered synthetic kukoamine A on BP in the Spontaneously Hypertensive Rat (SHR) laboratory animal model of hypertension. Prior to the hypertension study, we determined the safety of the synthetic kukoamine A in a single oral dose (5 or 10 mg kg -1 bodyweight) 14-day observational study in mice. No negative effects of the oral administration of kukoamine A were observed. We subsequently investigated the effect of daily oral doses of kukoamine A (0, 5, 10 mg kg -1 bodyweight) for 35 days using the SHR rat model of hypertension. The normotensive control Wistar Kyoto (WKY) strain was used to provide a baseline for normal BP in rats. We observed no effect of orally administered synthetic kukoamine A on arterial hypertension in this laboratory animal model of hypertension.

Tomato fruit stored below 12°C lose quality and can develop chilling injury upon subsequent transfer to a shelf temperature of 20°C. The more severe symptoms of altered fruit softening, uneven ripening and susceptibility to rots can cause postharvest losses. We compared the effects of exposure to mild (10°C) and severe chilling (4°C) on the fruit quality and transcriptome of 'Angelle', a cherry-type tomato, harvested at the red ripe stage. Storage at 4°C (but not at 10°C) for 27 days plus an additional 6 days at 20°C caused accelerated softening and the development of mealiness, both of which are commonly related to cell wall metabolism. Transcriptome analysis using RNA-Seq identified a range of transcripts encoding enzymes putatively involved in cell wall disassembly whose expression was strongly down-regulated at both 10 and 4°C, suggesting that accelerated softening at 4°C was due to factors unrelated to cell wall disassembly, such as reductions in turgor. In fruit exposed to severe chilling, the reduced transcript abundances of genes related to cell wall modification were predominantly irreversible and only partially restored upon rewarming of the fruit. Within 1 day of exposure to 4°C, large increases occurred in the expression of alternative oxidase, superoxide dismutase and several glutathione S-transferases, enzymes that protect cell contents from oxidative damage. Numerous heat shock proteins and chaperonins also showed large increases in expression, with genes showing peak transcript accumulation after different times of chilling exposure. These changes in transcript abundance were not induced at 10°C, and were reversible upon transfer of the fruit from 4 to 20°C. The data show that genes involved in cell wall modification and cellular protection have differential sensitivity to chilling temperatures, and exhibit different capacities for recovery upon rewarming of the fruit.

Selenium (Se) is an essential micronutrient for human health, entering the diet mainly through the consumption of plant material. Members of the Brassicaceae are Se-accumulators that can accumulate up to 1g Se kg−1 dry weight (DW) from the environment without apparent ill effect. The Brassicaceae also produce glucosinolates (GSLs), sulfur (S)-rich compounds that benefit human health. Radish (Raphanus sativus) has a unique GSL profile and is a Se-accumulating species that is part of the human diet as sprouts, greens and roots. In this report we describe the effects of Se-fertilisation on GSL production in radish during five stages of early development (from seed to mature salad greens) and on the transcript abundance of eight genes encoding enzymes involved in GSL metabolism. We tentatively identified (by tandem mass spectrometry) the selenium-containing glucosinolate, 4-(methylseleno)but-3-enyl glucosinolate, with the double bond geometry not resolved. Two related isothiocyanates were tentatively identified by Gas Chromatography-Mass Spectrometry as (E/Z?) isomers of 4-(methylseleno)but-3-enyl isothiocyanate. Se fertilisation of mature radish led to the presence of selenoglucosinolates in the seed. While GSL concentration generally reduced during radish development, GSL content was generally not affected by Se fertilisation, aside from the indole GSL, indol-3-ylmethyl glucosinolate, which increased on Se treatment, and the Se-GSLs, which significantly increased during development. The transcript abundance of genes involved in aliphatic GSL biosynthesis declined with Se treatment while that of genes involved in indole GSL biosynthesis tended to increase. APS kinase transcript abundance increased significantly in three of the four developmental stages following Se treatment. The remaining genes investigated were not significantly changed following Se treatment. We hypothesise that increased APS kinase expression in response to Se treatment is part of a general protection mechanism controlling the uptake of S and the production of S-containing compounds such as GSLs. The upregulation of genes encoding enzymes involved in indole GSL biosynthesis and a decrease in those involved in aliphatic GSL biosynthesis may be part of a similar mechanism protecting the plant’s GSL complement whilst limiting the amount of Se-GSLs produced.

Capsicums (bell peppers) are an important international crop that has specific postharvest handling requirements due to a high susceptibility to quality deterioration from water loss. When harvested green, capsicums are susceptible to chilling injury if stored below approximate to 7 degrees C for long periods, although red fruit can withstand lower temperatures. Chilling injury usually manifests as spots of surface pitting that can develop into large regions of pitted areas. Extending storage life to enable sea freight from countries distant from their final market (such as New Zealand) means that fruit must be exceptionally well cleaned to allow high humidity to be maintained during storage so that rots do not develop. A range of postharvest treatments that might reduce chilling injury is discussed, although few if any of these have entered commercial practice. This review also covers biology and consumer attributes including colour, taste and flavour, and texture.

The asparagus spear is a rapidly growing shoot, dependent on the crown and storage roots for substrate. Once harvested, spears have a very short shelf-life. Investigations to date point to a physiological cause of this deterioration rather than a pathogenic one. Since loss of membrane integrity is a notable feature of the postharvest deterioration, spears were treated immediately following harvest with cytokinin (which promotes membrane integrity), and jasmonic acid (produced by deteriorating membranes). Treated plant material was collected and monitored for physiological and compositional changes. Results show a reduction in postharvest elongation of spears treated with cytokinin, and a reduction of shelf-life of spears treated with jasmonic acid, when compared with control spears treated with water. Also an extension of shelf-life was observed for spears treated with cytokinin. We quantified jasmonates using ELISA in spears after harvest, and also in naturally senescing cladophylls. Jasmonate concentration increased in spears rapidly after harvest, which is most likely to be in response to wounding. Results also showed that jasmonates may be involved in desiccation stress and cessation of elongation in asparagus spears. Jasmonate production and metabolism appears to be more ordered during natural foliar senescence than during harvest induced senescence of the spear. Jasmonic acid and dihydrojasmonic acid are metabolised to cucurbic acid during the later stages of natural foliar senescence. The presence of jasmonates in asparagus spears was confirmed by electrospray ionisation mass spectrometry. This analysis also enabled to identify a novel jasmonate, tryptophan-dihydrojasmonic acid amino acid

The Brassicaceae are known for their capacity to produce and accumulate the sulfur (S)-rich glucosinolates, which have appreciable human health benefits. Selenium (Se) is chemically very similar to S and many plant enzymes appear unable to distinguish between these two elements. Thus Se may be metabolized through many of the S uptake and assimilation pathways. We were interested in the effect of Se-fertilization on the production of glucosinolate compounds in Brassicaceae. We fertilized broccoli, cauliflower and forage rape with Na2SeO4 and examined the glucosinolates produced in four tissues (tap root, stem, leaf and floret) of these plants using liquid chromatography-mass spectrometry (LC-MS). Several Se-containing glucosinolates were identified and measured. In each case, the Se atom substituted for the S atom normally found in the methylthioalkyl moiety of the glucosinolate and was presumably donated by selenomethionine. The highest concentration of these new Se-containing glucosinolates was in broccoli florets and forage rape roots. In forage rape leaves the majority of the methylthio class of glucosinolates was selenized. Se fertilization also appeared to increase the concentration of the non-selenized methylthioglucosinolates in the shoot tissues of these Brassica species. Our results show that Se and S metabolism of Brassica tissues vary in their responses to Se fertilization and that several enzymes of the glucosinolate biosynthetic and metabolism pathways can use Se in place of S to generate Se-containing glucosinolates.

In Brassica species, hydrolysis of (methylthio)glucosinolates produces sulfur-containing aglycons which have demonstrated anticancer benefits. Selenized Brassicaceae contain (methylseleno)glucosinolates and their selenium-containing aglycons. As a prelude to biological testing, broccoli, cauliflower, and forage rape plants were treated with sodium selenate and their tap roots, stems, leaves, and florets analyzed for selenoglucosinolates and their Se aglycons. Two new selenoglucosinolates were identified: glucoselenoraphanin in broccoli florets and glucoselenonasturtiin in forage rape roots. A new aglycon, selenoberteroin nitrile, was identified in forage rape. The major selenoglucosinolates were glucoselenoerucin in broccoli, glucoselenoiberverin in cauliflower, and glucoselenoerucin and glucoselenoberteroin in forage rape roots. In broccoli florets, the concentrations of selenglucosinolates exceeded those of their sulfur analogues. Fertilization with selenium slightly reduced (methylthio)glucosinolates and aglycons in the roots, but increased them in the florets, the leaves, and sometimes the stems. These discoveries provide a new avenue for investigating how consumption of Brassica vegetables and their organoselenides may promote human health.

Se is a trace element essential for human health due to the presence of several Se-requiring enzymes in the human body. Inadequate dietary intake of Se, leading to potential Se deficiency, has been a problem for populations living in countries with a low Se content in their soils (and therefore in the crops grown in them), such as Finland and New Zealand. An increased dietary intake of Se has been shown to provide health benefits beyond that of preventing the symptoms of Se deficiency, by reducing oxidative stress and boosting heart and lung function, and by reducing the incidence of certain cancers. Se supplementation of various fruit and vegetable species to levels within dietary recommendations is easily possible, with some Se-supplemented products (e.g., spinach, potatoes, tomatoes) being released commercially. Current research is investigating a second generation of crops enriched in organic forms of Se possessing powerful antioxidant or anticancer activity, such as methylselenocysteine or selenoglucosinolates. The product safety requirements for Se supplementation of fruit and vegetables must be rigorous to protect agricultural workers and consumers. For a commercial product, the biological variation in Se uptake and accumulation between individual plants or edible plant parts needs to be monitored and controlled through extensive product testing.

SCOPE:Selenium (Se) is a micronutrient essential for human health, including immune function. Previous research indicates that Se supplementation may cause a shift from T helper (Th)1- to Th2-type immune responses. We aim to test the potential health promoting effects of Se-enriched broccoli.METHODS AND RESULTS:In a human trial, 18 participants consumed control broccoli daily for 3 days. After a 3-day wash-out period, the participants were provided with Se-enriched broccoli containing 200 μg of Se per serving for 3 days. Plasma and peripheral blood mononuclear cell (PBMC) samples were collected at the start and end of each broccoli feeding period for analysis of total Se and measurement of cytokine production from PBMC stimulated with antigens ex vivo. Plasma Se content remained consistent throughout the control broccoli feeding period and the baseline of the Se-enriched broccoli period (1.22 μmol/L) and then significantly increased following 3 days of Se-enriched broccoli feeding. Interleukin (IL-2, IL-4, IL-5, IL-13, and IL-22) production from PBMC significantly increased after 3 days of Se-enriched broccoli feeding compared with baseline.CONCLUSION:This study indicates that consumption of Se-enriched broccoli may increase immune responses toward a range of immune challenges.

Rapid quantitative near-infrared Fourier transform Raman analyses of the key phytonutrients in carrots, polyacetylenes and carotenoids, are reported here for the first time. Solvent extracts of 31 carrot lines were analyzed for these phytonutrients by conventional methods, polyacetylenes by GC-FID and carotenoids by visible spectrophotometry. Carotenoid concentrations were 0-5586 μg g(-1) dry weight (DW). Polyacetylene concentrations were 74-4846 μg g(-1) DW, highest in wild carrots. The polyacetylenes were falcarinol, 6-1237 μg g(-1) DW; falcarindiol, 42-3475 μg g(-1) DW; and falcarindiol 3-acetate, 27-649 μg g(-1) DW. Strong Raman bands for carotenoids gave good correlation to results by visible spectrophotometry. A chemometric model capable of quantitating carotenoids from Raman data was developed. A classification model for rapidly distinguishing carrots with high and low polyacetylene (limit of detection = 1400 μg g(-1)) concentrations based on Raman spectral intensity in the region of 2250 cm(-1) was produced.

Volatiles from radiata forest litter were shown to inhibit seedling growth of Trifolium repens L. (white clover), Lolium perenne L. (perennial ryegrass), and Pinus radiata D. Don. Seed germination of ryegrass and radiata was also reduced. This effect was not due to C02, reduced 0 2 concentrations, or a compound soluble in water or paraffin wax. The authors have not yet shown that this effect occurs in the field. INTRODUCTION Pinus radiata D. Don is important economically in New Zealand not only as a forest crop but also when grown in association with agriculture. Under pure stands of radiata in Canterbury a thick layer of litter accumulates and the growth of seedlings of radiata and other species is sparse or absent. Because the lack of undergrowth might in part be due to allelopathy it was thought worthwhile to investigate the possible effects of radiata litter on the growth of seedlings of radiata and other plants. There have been reports of the production of volatile metabolites by fungal cultures (Hutchinson, 1973), and because radiata litter supports vigorous fungal growth the effect of volatile substances evolved from the litter on seed germination and seedling growth was investigated. MATERIALS A N D METHODS Basic Experimental Procedure Litter was collected from beneath a mature stand of Pinus radiata (39-yr old, 300 stems/ha) at Ashley Forest, Canterbury. Despite moist site conditions undergrowth was sparse, and there were very few radiata seedlings even though numerous seed wings were seen in the litter. In the first set of experiments cores (14 cm diam.) of the litter horizon, which ranged from 1.0 to 14.8 cm deep, were removed from positions determined by random * Present Address: Department of Microbiology, La Trobe University, Bundoora, Victoria 3083, Australia. N.Z. J. For . Sci. 5 (2): 165-70 (1975). 166 New Zealand Journal of Forestry Science Vol. 5 co-ordinates from within the sampling area (100 m). Twenty litter cores were placed in 18-litre tins fitted with inlet and outlet tubes (Fig. 1). In later experiments 40 cores of litter cut with a 10 cm diam, steel corer were placed in each tin.

Glucosinolates are sulphur-containing glycosides found in many Brassica spp. that are important because their aglycone hydrolysis products protect the plant from herbivores and exhibit anti-cancer properties in humans. Recently, synthetically produced selenium analogues have been shown to be more effective at suppressing cancers than their sulphur counterparts. Although selenium is incorporated into a number of Brassica amino acids and peptides, firm evidence has yet to be presented for the presence of selenium in the glucosinolates and their aglycones in planta. In this study broccoli and cauliflower florets, and roots of forage rape, all obtained from plants treated with sodium selenate, were analysed for the presence of organoselenides. GC-MS analysis of pentane/ether extracts identified six organoselenium compounds including selenium analogues of known myrosinase-derived Brassica volatiles: 4-(methylseleno)butanenitrile, 5-(methylseleno)pentanenitrile, 3-(methylseleno)propylisothiocyanate, 4-(methylseleno)butylisothiocyanate, and 5-(methylseleno)pentylisothiocyanate. LC-MS analysis of ethanolic extracts identified three selenoglucosinolates: 3-(methylseleno)propylglucosinolate (glucoselenoiberverin), 4-(methylseleno)butylglucosinolate (glucoselenoerucin), and 5-(methylseleno)pentylglucosinolate (glucoselenoberteroin). LC-MS/MS analysis was used to locate the position of the selenium atom in the selenoglucosinolate and indicates preferential incorporation of selenium via selenomethionine into the methylselenyl moiety rather than into the sulphate or β-thioglucose groups. In forage rape, selenoglucosinolates and their aglycones (mainly isothiocyanates), occurred at concentrations up to 10% and 70%, respectively, of their sulphur analogues. In broccoli, concentrations of the selenoglucosinolates and their aglycones (mainly nitriles) were up to 60% and 1300%, respectively of their sulphur analogues. These findings indicate the potential for the incorporation of high levels of selenium into Brassica glucosinolates.

Metabolic heat rates, determined by microcalorimetry, were used to measure the effect of controlled atmospheres (CAs) and elevated temperatures on the stored-product insects Sitophilus oryzae (rice weevil) and Tribolium confusum (confused flour beetle). Results for larval and adult stages in air, and in a range of low O2 and/or high CO2 CAs, at temperatures from 15 to 45°C, showed the general effectiveness of such atmospheres in lowering the lethal temperatures relative to those in air. Effects on adult S. oryzae at 25°C were explored in more detail in experiments using the following conditions: exposure to anoxic CAs for extended times; exposure to hypoxic CAs; and simulated hermetic storage. A simple scanning calorimetric method was developed for determining lethal temperatures and a combined thermo-gravimetric and differential thermal-analysis method was used to interpret the thermal events, due to loss of water, occurring at and above these temperatures.

Broccoli (Brassica oleracea var. italica) deteriorates rapidly following harvest. The two plant hormones ethylene and cytokinin are known to act antagonistically on harvest-induced senescence in broccoli: ethylene by accelerating the process, and cytokinin by delaying it. To determine the level at which these hormones influenced senescence, we isolated and monitored the expression of genes normally associated with senescence in broccoli florets treated with exogenous 6-benzyl aminopurine (6-BAP), 1-aminocyclopropane-1-carboxylic acid (ACC), a combination of 6-BAP and ACC, and sucrose, in the five days following harvest. Exogenous 6-BAP caused both a reduction (BoACO) and an increase (BoACS) in ethylene biosynthetic gene expression. The expression of genes used as senescence markers, BoCP5 and BoMT1, was reduced, whereas BoCAB1 levels were maintained after harvest in response to exogenous 6-BAP. In addition, the expression of genes encoding sucrose transporters (BoSUC1 and BoSUC2) and carbohydrate metabolizing enzymes (BoINV1 and BoHK1) was also reduced upon 6-BAP feeding. Interestingly, the addition of ACC prevented the 6-BAP-induced increase in expression of BoACS, but 6-BAP negated the ACC-induced increase in expression of BoACO. The culmination of these results indicates a significant role for cytokinin in the delay of senescence. The implication that cytokinin regulates postharvest senescence in broccoli by inhibiting ethylene perception and/or biosynthesis, thus regulating carbohydrate transport and metabolism, as well as senescence-associated gene expression, is discussed and a model presented.

Pinus radiata D. Don is an important tree in New Zealand where it is widely grown for timber and, to a lesser extent, in association with pasture species. In pure stands of P. radiata in Canterbury, poor development of undergrowth may in part be caused by volatile inhibitory substances released from the decomposing litter. In previous work it was shown that vapour from incubated P. radiata litter inhibited seedling growth. This inhibition was attributed to ethylene which was present in the vapour. Experiments were carried out to investigate the effects of litter vapour on the germination of Trifolium repens (clover) and Lolium perenne L . (ryegrass) seed. Clover germination was delayed by litter vapour, but when the vapour was diluted 10-fold a stimulation of germination was observed. Ryegrass germination was delayed by both undiluted vapour and a 10-fold dilution. When ethylene was removed from the litter vapour the stimulatory effect on clover germination was lost, but no change occurred in the inhibitory effect on ryegrass germination. Removing CO2 from litter vapour capable of inhibiting clover germination removed the inhibition and also greatly reduced the inhibitory effect on ryegrass germination. These results suggest that ethylene and CO2 in the litter vapour could be causing the observed effects. Ryegrass germination was inhibited by both ethylene (5 μ l/l) and CO2 (100 μp/p) but a mixture of ethylene and CO2 caused no additional inhibition. Clover seed treated with six concentrations of ethylene at four concentrations of CO2 showed stimulated germination both by CO2 in the absence of ethylene and by ethylene in the absence of CO2. As the CO2 concentration increased, the stimulation by ethylene was reduced and at ethylene concentrations above 0.5 μ l / 1, CO2 caused a reduction in germination rate. The lowest germination rate observed was in the absence of both ethylene and CO2.