Relationship of ammonium ion and abscisic acid in bunchstem tissue to the incidence of the disorder bunchstem necrosis in grapevine

Bunchstem tissue from three Cabernet Sauvignon vineyards during three years were analysed for ammonium ion and abscisic acid to test whether their levels correlated with the incidence of the disorder bunchstem necrosis (BSN, Stiellähme). Levels of free ammonium ion, known to be toxic to plant tissue when excessive, were found to be low, considerably lower than those reported in the literature. Neither free nor released ammonium ion levels correlated with BSN incidence. Similarly the levels of abscisic acid, a stress hormone that can induce BSN symptoms when applied to bunches, showed no correlation with BSN incidence.     

Incidence of grapevine bunchstem necrosis in South Australia: effects of region, year and pruning

The incidence of grapevine bunchstem necrosis (BSN) in cv. Cabernet Sauvignon was assessed in three South Australian regions during three years. The percentage of bunches affected varied widely—from nil to 26%-between years and regions. At the site with most BSN, high incidence was related to lower temperatures during 20 days before flowering and not to low temperatures during flowering. Also, incidence was higher when rain fell during veraison. Minimally pruned vines had significantly less BSN than spur-pruned vines in each of the three test years.     

The relationship between the expression of abscisic acid biosynthesis genes, accumulation of abscisic acid and the promotion of Vitis vinifera L. berry ripening by abscisic acid

Background and Aims:  Grapevines ( Vitis vinifera L.) are considered to have non-climacteric fruit, but the trigger initiating ripening (veraison) is poorly understood. This study aimed to further investigate the role of abscisic acid (ABA) during berry ripening.
Methods and Results:  In field-grown grapes over three seasons, free ABA levels increased at veraison then subsequently declined to low levels. Bound ABA increased as the free ABA level decreased after 10–11 weeks post-flowering (wpf), but ABA must also be degraded and/or exported. The absence of a large pool of bound ABA before veraison makes it unlikely that the increase in free ABA is due to the mobilization of conjugated ABA. The expression pattern of genes crucial for ABA synthesis, zeaxanthin epoxidase and two 9-cis-epoxycartenoid dioxygenases (NCEDs) indicates that berries may have the potential to synthesize ABA in situ . However, the expression profile of these genes did not correlate well with ABA levels indicating that ABA accumulation is under more complex control. The application of (+)-ABA advanced ripening as measured by colour formation, berry size increase and to a lesser extent sugar accumulation and altered the expression of one of the NCED genes.
Conclusions:  The changes in berry ABA levels around the time of veraison, which influence the timing of ripening, are under complex developmental control.
Significance of the Study:  The improved understanding of the control of berry ripening is vital to attempts to successfully manipulate this process.     

脱落酸处理对苹果成熟、乙烯合成及其信号转导基因表达的影响

为研究脱落酸（abscisic acid,ABA）对苹果果实采后成熟、乙烯合成及其信号转导基因表达的影响,本实验以‘Granny Smith’苹果果实为实验材料,将其进行外源ABA处理后置于20 ℃贮藏（以无菌水处理为对照）,测定贮藏过程中的硬度、可滴定酸质量分数、纤维素酶活力、果胶甲酯酶活力、叶绿素含量、内源ABA含量、乙烯产生速率及乙烯生物合成基因（ACO1、ACO2、ACS1、ACS3）、苹果乙烯信号转导基因（ERS1、ERS2、ETR2、ERF3、ERF4、ERF5）的表达量。结果表明,与对照组相比,ABA处理能降低苹果果实贮藏过程中的硬度和可滴定酸质量分数,提高果实中的纤维素酶和果胶甲酯酶活性,促进叶绿素a、叶绿素b和总叶绿素含量降低。定量聚合酶链式反应分析结果表明,与对照组相比,ABA处理能够显著提高苹果乙烯生物合成基因的表达量（P＜0.05）。同时,参与苹果乙烯信号转导的ERS2、ETR2和ERF3、ERF4、ERF5表达量随着果实采后成熟明显增加,并且ABA处理组果实中的表达量总体显著高于对照组（P＜0.05）。综上,外源ABA处理能够促进苹果内源ABA的合成,提高苹果乙烯生物合基因和信号转导基因的表达,促进苹果内源乙烯合成和乙烯信号的转导,加快苹果果实的采后成熟进程。     

脱落酸的生物合成及对水果成熟的调控研究进展

作为一种重要的植物激素,脱落酸（abscisic acid,ABA）除具有引起植物芽体休眠、叶子脱落、气孔关闭、抑制植株生长和增强植物抗逆性等生理作用外,在果实生长发育和成熟衰老的过程中也具有重要的调控作用。高等植物组织中ABA生物合成主要是通过C40类胡萝卜素的间接途径来实现的。植物内源ABA的含量水平处于动态平衡状态,受其生物合成和分解代谢等因素影响,在此过程中有关基因转录表达水平和酶活性起着关键作用。内源ABA含量的升高会导致水果成熟和果肉软化,ABA可能同时调控了呼吸跃变型和呼吸非跃变型水果的成熟衰老。探究ABA的生物合成及其调控作用,对揭示水果的生长发育、品质形成、着色软化、成熟衰老等过程具有重要的现实意义。本文综述了ABA及其生成代谢相关基因调控水果成熟的研究进展,并展望了ABA在提高水果品质、延长水果货架期等方面的商业应用。     

Effects of partial rootzone drying on yield, ripening and berry ABA in potted Tempranillo grapevines with split roots

Our objective was to investigate whether grape berry growth and colour development is associated with variation in abscisic acid (ABA) levels during ripening under an irrigation regime of partial rootzone drying (PRD). The study was carried out using container‐grown Tempranillo grapevines (established as fruit‐bearing cuttings) with a split root system (occupying two contiguous pots) and grown under controlled conditions. Three irrigation treatments were imposed – a control (well watered), and two forms of deficit irrigation, viz. partial rootzone drying (PRD), and sustained deficit irrigation (SDI). Under SDI, a given volume of irrigation water was applied uniformly and simultaneously to both sides of the split roots of each vine. Under the PRD regime, the same total volume of irrigation was applied, but as separate allocations to each side of the split root system in turn, and alternating on a 10‐day cycle. Because both deficit treatments received the same total amount of irrigation water (about 50% of the volume applied to controls), we were able to distinguish between the effects of deficit irrigation per se, versus any specific impact PRD might be having on vine performance. Outcomes were as follows. Compared to well‐watered control vines, yield per plant, and weight per bunch were both reduced significantly under SDI, but were sustained close to control values under the PRD regime. SDI and PRD thus differed significantly in their respective impacts on vine performance, and comparing just these two forms of deficit irrigation, PRD resulted in greater yield, higher bunch weight, bigger leaf area and increased berry weight compared with the SDI treatment. Moreover, PRD also induced greater accumulation of skin anthocyanins at harvest, compared to SDI. Berry ABA concentration increased continuously throughout veraison, achieving a maximum at the end of this period. The increase of berry ABA concentration was earlier and faster in PRD than in SDI, which exhibited only a slight increase in berry ABA by the end of veraison. These distinctive responses to PRD compared to SDI imply that the alternating wet‐dry cycles of PRD, rather than simply a deficit irrigation, as in SDI, had a distinctive effect on growth, ripening and berry composition. Our data imply that these different responses might be related to ABA physiology, and especially to ABA levels in berries during ripening.     

赤霞珠葡萄生长发育过程中内源激素的变化及其与果实成熟的关系

为研究赤霞珠葡萄果实发育过程中不同组织(果皮、果肉和种子)内源激素的含量变化及其与果实成熟的关系,用高效液相色谱-质谱联用技术测定果实发育过程中果皮、果肉以及种子中脱落酸(abscisic acid,ABA)、生长素(indole acetic acid,IAA)、赤霉素(gibberellin A_3,GA_3)、茉莉酸(jasmonic acid,JA)和水杨酸(salicylic acid,SA)的含量。结果发现,在葡萄果实生长发育过程中,葡萄果皮和果皮中ABA含量呈双S型变化,花后20 d左右,ABA含量较高,随着果实膨大开始下降,随后开始上升,至转色中期达到最大值,随着果实的成熟缓慢下降;果皮、果肉和种子中GA_3含量均是从果实膨大期开始上升,膨大后期下降,随后在转色初期又开始上升,随后下降;JA含量的变化与GA_3类似;果皮和果肉中IAA含量首先略微下降,在果实快速生长期迅速上升,并达到峰值,随着果实进入转色期,含量逐渐下降并保持稳定,果实膨大期之前,种子中IAA含量较高,随着果实膨大降低,并维持在较低水平,SA含量的变化与IAA类似。结论:ABA、GA_3、JA含量与赤霞珠果实成熟有关,IAA、GA_3、SA、JA含量与赤霞珠果实生长有关。     

Effects of exogenous abscisic acid on fruit quality, antioxidant capacities, and phytochemical contents of southern high bush blueberries

Abscisic acid (ABA) is a plant growth regulator that has a potential to increase antioxidant capacity and phenolic content of fruits and vegetables. The objective of this study was to examine whether an exogenous ABA application can positively affect fruit quality, antioxidant capacity, and phytochemical content of southern high bush blueberries (Vaccinium darrowii). Two varieties, namely Star and Windsor, were tested with ABA water solutions of three concentrations (0, 200, and 400 ppm) using a randomised complete block design. Results showed that ABA significantly increased the firmness of berries in both varieties, suggesting a ripening delay effect. Such effect was more pronounced in Windsor variety as reflected by a lower percentage of ripe berries and smaller sized berries on ABA treated bushes. In conclusion, ABA delayed the ripening of blueberries, but did not affect total phenolic content, antioxidant capacity, or the content of individual phytochemicals in ripe blueberries.     

ABA和乙烯利处理对京优葡萄果皮花色苷和果实品质的影响

以京优葡萄为试材,研究不同浓度ABA和乙烯利处理果穗对果皮花色苷含量及果实品质的影响.结果表明,ABA和乙烯利处理皆能促进果实软化、有机酸降解、可溶性固形物和果皮色素积累,具有促进果实成熟的作用.乙烯利软化果实的效果明显好于ABA,但促进果实可溶性固形物积累的效果弱于ABA.300 mg/L ABA和乙烯利处理的催熟效果不明显,仅能使果实提前3～6d成熟;高浓度乙烯利处理(600 mg/L和900 mg/L)可以有效促进果实成熟,但会导致着色不良、裂果和落果等问题;600 mg/LABA处理效果最佳,可以使果实提前13～16 d成熟,且果实理化指标皆能满足商品要求.     

The effect of chemical treatment on reduction of aflatoxins and ochratoxin A in black and white pepper during washing

The effect of 18 different chemicals, which included acidic compounds (sulfuric acid, chloridric acid, phosphoric acid, benzoic acid, citric acid, acetic acid), alkaline compounds (ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide), salts (acetate ammonium, sodium bisulfite, sodium hydrosulfite, sodium chloride, sodium sulfate) and oxidising agents (hydrogen peroxide, sodium hypochlorite), on the reduction of aflatoxins B(1), B(2), G(1) and G(2) and ochratoxin A (OTA) was investigated in black and white pepper. OTA and aflatoxins were determined using HPLC after immunoaffinity column clean-up. Almost all of the applied chemicals showed a significant degree of reduction on mycotoxins (p < 0.05). The lowest and highest reduction of aflatoxin B(1), which is the most dangerous aflatoxin, was 20.5% ± 2.7% using benzoic acid and 54.5% ± 2.7% using sodium hydroxide. There was no significant difference between black and white peppers (p < 0.05).     

Effect of delayed gutting on biogenic amine contents during ripening of European anchovies

The effect of delayed gutting on biogenic amine formation during ripening of European anchovies (Engraulis encrasicholus) was studied. The main difference between the two processes was the use of gutted or ungutted fish in the first step of ripening. Biogenic amines and microbial counts were studied in seven batches of samples taken during manufacturing from fresh anchovies and from anchovies throughout ripening. The formation of amines commonly related to fish spoilage (histamine, tyramine, cadaverine, putrescine and agmatine) was significantly higher in the first step of ripening of batches in ungutted fish. In contrast, no differences were observed between the content of the natural polyamines spermine and spermidine.     

Auto‐fluorescence for analysis of ripening in Thompson Seedless and colour in Crimson Seedless table grapes

Background and Aims: Ripening of table grapes is routinely followed by measurement of soluble solids, acidity, colour and firmness. Non‐destructive means to measure ripening can be of great value to determine optimal harvest time and to compare the effect of treatments on ripening. Methods and Results: The portable fluorescence detector (Multiplex III, Force A, France) generates 12 signals which are processed to ratios which compensate for the structural complexity of the cluster. Sampling was carried out in a Thompson Seedless vineyard in four blocks and over 9 weeks. The simple fluorescence ratio (SFR_R) (correlated to chlorophyll level) decreased exponentially with an R² value of 0.97, while flourscence excitation ratio (FER_RG) (correlated to anthocyanin level) displayed an increasing linear trend with an R² of 0.98. The flavonoids (FLAV) ratio which was shown to correlate to the level of flavonoids increased during the first 5 weeks of veraison and then reached a steady level. In an experiment on Crimson Seedless grapes, application of abscisic acid (ABA) resulted in a dose response using the anthocyanin (ANTH) ratio which is the log expression of FER_RG. In a further experiment on Crimson Seedless, the clusters were separated into three colour groups after veraison; ABA and Ethrel were applied, leaving untreated clusters in each colour group as control. The ANTH ratio was able to quantify a significant increase in colour for each group with respect to its control. Conclusions: The results suggest that portable fluorescence detectors may become important tools to study ripening of table grapes. Significance of the Study: This is the first report of the use of fluorescence to follow ripening of table grapes.     

The effect of chemical treatment on reduction of aflatoxins and ochratoxin A in black and white pepper during washing

The effect of 18 different chemicals, which included acidic compounds (sulfuric acid, chloridric acid, phosphoric acid, benzoic acid, citric acid, acetic acid), alkaline compounds (ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide), salts (acetate ammonium, sodium bisulfite, sodium hydrosulfite, sodium chloride, sodium sulfate) and oxidising agents (hydrogen peroxide, sodium hypochlorite), on the reduction of aflatoxins B₁, B₂, G₁ and G₂ and ochratoxin A (OTA) was investigated in black and white pepper. OTA and aflatoxins were determined using HPLC after immunoaffinity column clean-up. Almost all of the applied chemicals showed a significant degree of reduction on mycotoxins (p?<?0.05). The lowest and highest reduction of aflatoxin B₁, which is the most dangerous aflatoxin, was 20.5%?±?2.7% using benzoic acid and 54.5%?±?2.7% using sodium hydroxide. There was no significant difference between black and white peppers (p?<?0.05).     

Involvement of abscisic acid and polyamines in berry ripening of Vitis vinifera (L.) subjected to water deficit irrigation

Background and Aims: Partial rootzone drying (PRD) is an irrigation system that permits better control of vegetative growth without reducing fruit yield. However, little is known about how grapevine reproductive development is regulated when irrigated under PRD. Therefore, the aim of this work was to investigate the relationship between abscisic acid (ABA) and polyamines (PAs) in leaves and berries during ripening, and how hormonal balance is affected under different irrigation regimes.
Methods and Results: The study was carried out using container-grown Superior Seedless grapevines with a split-root system and grown under controlled conditions in a greenhouse. Three irrigation treatments were imposed: control (well watered), and two forms of deficit irrigation – PRD and sustained deficit irrigation (SDI). PRD plants have higher yield and berry size than SDI vines. At the onset of veraison, PRD berries have higher ABA, free PAs and free to bound PA ratio than other treatments.
Conclusions: Although the restriction of vegetative growth in PRD might be partly a response to the volume of water applied and therefore similar to a SDI response, our results suggest that specific hormonal factors may explain the effects on reproductive growth and yield.
Significance of the Study: The study demonstrates that changes induced in berry ABA during PRD conditions could be counterbalanced by changes in PA metabolism so that berry size and yield are maintained.     

The effect of water stress and form of nitrogen on the incidence of blossom-end rot in tomatoes

The effects of water stress, ammonium sulphate, sodium nitrate and ammonium nitrate on the incidence of blossom-end rot (BER) in tomatoes was studied, using plants grown in peat modules. There was little evidence that water stress per se affected BER incidence, which was largely determined by the ammonium ion, as found in previous studies. Water stress increased ammonium and nitrate levels in both the peat modules and the leaves of the plants. This effect may account for the relation between moisture stress and BER reported by others.     

Influence of potassium nutrition and water stress on the content of abscisic acid in grains and flag leaves of wheat during grain development

Increasing the potassium (K) supply to wheat plants grown in pots extended the period of grain filling and increased the rate of grain growth, thus increasing the single grain weight. In all K treatments abscisic acid (ABA) content in the grain reached a maximum and this occurred when the growth rate of the grain declined and full ripening commenced. Increasing the K supply delayed the occurrence of the ABA maximum and reduced its absolute value. It seems that an extension of the grain filling period by better K nutrition might not only be due to a longer production of assimilates, but also due to a retarded and lower production of ABA in the grain. This result is supported by the finding that withholding of water supply for 1-week periods during grain development increased ABA content in the grain and reduced single grain weight.     

Effect of proteolytic starter cultures of Staphylococcus spp. on biogenic amine formation during the ripening of dry fermented sausages

The effect of proteolytic starter cultures of Staphylococcus carnosus and Staphylococcus xylosus on biogenic amine production was examined during the fermentation process of dry sausages. Microbial counts (lactic acid bacteria, Micrococcaceae and Enterobactenaceae), pH, moisture and proteolysis-related parameters were also studied. The polyamines spermine and spermidine were the main amines found in the raw material and they only showed slight fluctuations during the fermentation. The four elaborated batches presented a significant (P < 0.001) formation of tyramine and putrescine. The main rate of amine production was during the first three days, when a sharp pH decrease and the development of lactic acid bacteria occurred. Sausages fermented with starters had lower amounts of tyramine than naturally fermented sausages (control), but differences in the Micrococcaceae counts were only significant during the first week of the ripening process. A slight formation of diaminopropane, cadaverine, agmatine, tryptamine and phenylethylamine was observed. The amounts of histamine were constant and remained below 0.5 mg/kg of dry matter, while serotonin, octopamine and dopamine were not detected. The sausages with Staphylococcus as starter culture showed strong proteolysis that was correlated with higher pH values than those of the control sausages. However, no positive correlation was found between the proteolysis index and biogenic amine production. Since proteolysis was stronger during the second half of the ripening process, the release of free amino acids as amine precursors occurred later than the early amine production.     

Abscisic Acid in the Response of ‘Fortune’ Mandarins to Chilling. Effect of Maturity and High-Temperature Conditioning

The possible role of abscisic acid (ABA) and peel colour in chilling tolerance of ‘Fortune’ mandarins has been examined. Fruit stored at 2·5°C, but not at 12°C, showed pitting damage. The degree of damage changed considerably during development and maturity from November until May. Green fruit were more tolerant to chilling injury (CI). After colour break, chilling susceptibility increased from the beginning of December until January and February (the coolest season during the growing period) and declined towards May. This trend did not parallel changes in fruit colour index or free and bound ABA levels, which increased from November until May. At the time of chloroplast transformation to chromoplast a noticeable shift in free but not in bound ABA occurred. During storage, free ABA levels increased in fruits stored at 12°C, but not at 2·5°C. Changes in ABA with storage temperature depended on the stage of maturity of the fruits, but not on their susceptibility to CI. It has also been shown that there was no relationship between ABA content following exposure to 37°C and chilling tolerance. At all stages of maturity, the susceptibility of the fruits to CI and the free ABA levels of the flavedo decreased after conditioning the fruits for 3 days at 37°C. After storage at 2·5°C, the ABA levels of the conditioned fruit were similar or even lower than those of non-conditioned fruit. Treatment of fruit for 3 days with 10 μl litre^-1 ethylene increased free ABA about four times, whereas bound ABA remained nearly constant. This treatment enhanced cold-induced peel damage after prolonged storage. Thus, the ethylene-induced changes in free ABA appear not to be related to the induced changes in chilling susceptibility. The results obtained indicated, therefore, that free and bound ABA appear not to be involved on the adaptative mechanism developed in ‘Fortune’ mandarins to cope with chilling stress. © 1997 SCI.     

Effects of high-pressure treatment on free fatty acids release during ripening of ewes' milk cheese

The free fatty acid (FFA) profile of high pressure treated ewes' milk cheeses were studied to assess the effect of pressure treatment on cheese lipolysis. Cheeses were treated at 200, 300, 400 or 500 MPa (2P to 5P) at two stages of ripening (after 1 and 15 days of manufacturing; P1 and P15) and FFA were assayed at 1, 15 and 60 d ripening. On the first day of ripening, 3P1-cheeses showed levels of FFA twice that of the control cheeses. However, no significant differences were found between 3P1 and control cheeses at 60 d ripening. On the contrary, 4P1 and 5P1-cheeses had the lowest total FFA levels. The point at which pressure treatment was applied influenced the FFA profile of cheeses; cheeses pressurized at pressures<400 MPa on the first day of ripening were more similar to untreated cheeses than their homologues treated at 15 d.     

草莓果实成熟衰老影响因子及其调控机制研究进展

草莓味道可口,营养丰富,是世界上栽培最广泛的水果之一,但其生育周期短,采后极易衰老腐烂,不耐贮藏。因此,研究草莓果实成熟衰老相关影响因子及其调控机制意义重大。本文就近年来草莓果实成熟衰老过程中植物激素（乙烯、脱落酸）、相关酶类（脂肪氧合酶、抗氧化酶类、软化酶类）、外源物质（Ca2+、钙调素、NO、热水）和成熟衰老相关基因（PLDa基因、FAD基因家族、细胞壁水解酶相关基因）及其调控机制进行综述,认为内源激素和酶类等在不同层次上发挥着作用,直接或间接通过影响乙烯、NO等小分子物质发挥作用,相互影响,共同调控着果实的成熟衰老进程。基因层面的研究尚处于起步阶段,可能是通过编码细胞膜和细胞壁的合成分解相关酶类来发挥作用。本文旨在为草莓采后生理、贮藏保鲜的研究提供综合信息。