采后光照条件对白凤桃果实品质和挥发性香气物质形成的影响

研究了白凤桃果实贮藏过程中光照条件对果实成熟的影响。在7月12日(未熟期)和7月16日(硬熟期)采收果实,分别贮藏在光条件(白色荧光灯照明,果顶部光强为80μmol m~(-2)s~(-1))和暗条件中,室温均为25℃。硬熟期采收果实贮藏在光条件下,达到完熟期时,乙烯生成量较低。果肉的硬度在各个采收期,各种贮藏条件下均没有差别。光条件贮藏果实中花青苷含量较高。未熟期采收果实贮藏在光条件下时,可溶性固形物含量增加较多。光条件贮藏果实中天冬酰胺的下降比暗贮藏果实中更多。各时期采收的果实中,在光下贮藏时,果肉和果皮γ-癸内酯和γ-十二内酯的含量都明显增加。以上结果表明,白凤桃果实采收后在光下贮藏,可以明显改善果实的品质。     

Tomato fruit ascorbic acid content is linked with monodehydroascorbate reductase activity and tolerance to chilling stress

Quantitative trait loci (QTL) mapping is a step towards the identification of factors regulating traits such as fruit ascorbic acid content. A previously identified QTL controlling variations in tomato fruit ascorbic acid has been fine mapped and reveals that the QTL has a polygenic and epistatic architecture. A monodehydroascorbate reductase (MDHAR) allele is a candidate for a proportion of the increase in fruit ascorbic acid content. The MDHAR enzyme is active in different stages of fruit ripening, shows increased activity in the introgression lines containing the wild-type ( Solanum pennellii ) allele, and responds to chilling injury in tomato along with the reduced/oxidized ascorbate ratio. Low temperature storage of different tomato introgression lines with all or part of the QTL for ascorbic acid and with or without the wild MDHAR allele shows that enzyme activity explains 84% of the variation in the reduced ascorbic acid levels of tomato fruit following storage at 4 °C, compared with 38% at harvest under non-stress conditions. A role is indicated for MDHAR in the maintenance of ascorbate levels in fruit under stress conditions. Furthermore, an increased fruit MDHAR activity and a lower oxidation level of the fruit ascorbate pool are correlated with decreased loss of firmness because of chilling injury.     

黄肉红心猕猴桃‘东红’果实在不同贮藏方式下的生理和品质变化研究

以中华猕猴桃( Actinidia chinensis Planch.)黄肉红心新品种‘东红’为材料,对其果实在常温和低温贮藏方式下的生理及品质变化进行了研究。结果表明,果实硬度在2种贮藏方式下均呈先快速下降后缓慢下降的趋势。可溶性固形物含量、总糖含量、固酸比和糖酸比等4个品质指标均表现为先快速上升后维持在较高水平(低温贮藏下)或继续小幅上升(常温贮藏下)的趋势。总酸含量整体上均呈现逐渐下降之势,至果实软熟时稳定在0. 9%的水平。维生素C含量却在常温贮藏下基本呈逐渐上升之势,而在低温贮藏下大致表现为先上升后轻微下降。果实失重率和腐烂率均随贮藏时间的延长而逐渐增加,在常温贮藏时上升较快,而在低温贮藏时上升非常缓慢。总体而言,‘东红’果实主要的生理和品质指标在常温贮藏2 ~ 3周后或低温贮藏9周后发生明显转变,果实进入可食用阶段;并且继续低温贮藏15周内还能较好地保持果实品质,耐贮性较好。     

黄肉红心猕猴桃‘东红’果实在不同贮藏方式下的生理和品质变化研究

以中华猕猴桃（Actinidia chinensis Planch.）黄肉红心新品种‘东红’为材料,对其果实在常温和低温贮藏方式下的生理及品质变化进行了研究。结果表明,果实硬度在2种贮藏方式下均呈先快速下降后缓慢下降的趋势。可溶性固形物含量、总糖含量、固酸比和糖酸比等4个品质指标均表现为先快速上升后维持在较高水平（低温贮藏下）或继续小幅上升（常温贮藏下）的趋势。总酸含量整体上均呈现逐渐下降之势,至果实软熟时稳定在0.9%的水平。维生素C含量却在常温贮藏下基本呈逐渐上升之势,而在低温贮藏下大致表现为先上升后轻微下降。果实失重率和腐烂率均随贮藏时间的延长而逐渐增加,在常温贮藏时上升较快,而在低温贮藏时上升非常缓慢。总体而言,‘东红’果实主要的生理和品质指标在常温贮藏2~3周后或低温贮藏9周后发生明显转变,果实进入可食用阶段;并且继续低温贮藏15周内还能较好地保持果实品质,耐贮性较好。     

三个产地猕猴桃品种‘金梅’在低温贮藏及货架期内的采后生理和品质变化

以湖北武汉、湖南花垣和贵州大方3个不同产地的中华猕猴桃（Actinidia chinensis Planch.）黄肉新品种‘金梅’果实为材料,对‘金梅’果实在低温贮藏和常温货架期内的生理特征和品质变化规律进行研究。结果显示：3个产地‘金梅’的果实硬度均在低温贮藏12周后快速下降至可食用硬度水平;而可溶性固形物含量（SSC）和总糖含量均表现为先快速上升然后稳定在较高水平,其中大方果实的SSC和总糖含量仅低温贮藏3周后就较早上升到稳定水平,但低于武汉和花垣的果实。3地‘金梅’果实中总酸含量则在较小的范围内波动,在武汉、花垣和大方产的软熟果实中含量依次降低。3地‘金梅’果实中维生素C含量约在70~90 mg/100 g鲜重范围内小幅波动,其中花垣‘金梅’维生素C含量整体较低。3地‘金梅’果实在低温贮藏过程中均表现出较高的失重率和较低的腐烂率,其中大方果实失重率低于武汉和花垣,但其较早出现较高的腐烂率。花垣和大方‘金梅’果实在分别低温贮藏4、12、20周后转入到常温货架期的寿命可达4、3、2周之久;其中,大方‘金梅’较早较快软熟,并且其SSC含量明显低于花垣‘金梅’。研究结果表明3地‘金梅’均表现出较好的耐贮性和较长的货架期,其中花垣‘金梅’表现出较好的果实综合品质,可能与其干物质含量较高有关。     

Date palm,potential source for refined sugar

The total sugars in the mesocarp of the date palm fruit is between 70 and 80%. Approximately 60% of the dry weight of the mesocarp at the Khalal and early Rutab stages of fruit development is sucrose. High-yielding varieties of date palm have fruit yield potentials of 12.0 tons/ha, equivalent to an estimated production of 7.2 tons/ha of sucrose if the fruit is harvested at the stage of maximum sucrose accumulation. The estimated sucrose production from the date palm compares very favourably with the world average of 6.6 tons/ha for canesugar and the beet sugar average of 5.6 tons/ha for Europe. The relatively high sugar content of the fruit suggests that the date palm may have an important agro-industrial future as a potential source for refined sugar.     

不同贮藏条件对沙田柚果实苦味物质含量的影响

沙田柚原产广西,营养丰富且适合高血压和糖尿病等患者食用,近年来在沙田柚产业中存在品质下降、有苦味、异味生成等问题。为了研究不同贮藏条件下沙田柚苦味物质的含量变化,该文利用高效液相色谱仪,对室温包薄膜袋(A)、室温不包薄膜袋(B)和4℃低温不包薄膜袋(C)三种不同贮藏条件下,沙田柚外果皮、中果皮、囊衣、汁胞和种子中柚皮苷、柠檬苦素和诺米林在贮藏过程中的含量变化进行了测定。结果表明：沙田柚果实苦味物质以柚皮苷为主,主要分布在中果皮和囊衣中,柠檬苦素主要分布在种子和外果皮中,诺米林主要分布在种子中。各处理果实在贮藏过程中苦味物质含量变化不同,其中柚皮苷含量略有上升,柠檬苦素和诺米林含量整体呈下降趋势,略有波动,而汁胞中柠檬苦素和诺米林含量先上升再下降。三种不同贮藏条件相比,4℃低温不包薄膜袋贮藏的果实汁胞中柚皮苷和柠檬苦素的含量最高,在贮藏第30天,A、B、C 三种不同贮藏条件果实汁胞中柚皮苷含量分别为(0.139±0.006)、(0.190±0.009)和(0.194±0.019) mg?g-1,柠檬苦素含量分别为(47.28±1.91)、(33.64±1.90)和(84.19±5.56)μg?g-1。与此相反,外果皮、中果皮、囊衣和种子中柚皮苷、柠檬苦素和诺米林含量最低。该研究结果为采后沙田柚贮藏保鲜方式的选择提供了理论指导。     

田间应用拮抗酵母菌对甜樱桃果实采后病害的防治效果

研究了应用拮抗酵母菌丝孢酵母(Trichosporon pullulans(Lindner.)Diddens et Lodder)、罗伦隐球酵母(Cryptococcus laurentii(Kuffer.)Skinner)和粘红酵母(Rhodotorula glutinis(Fresenius)Harrison)后拮抗菌在果实表面的繁殖能力以及对不同贮藏条件下甜樱桃(Pranus avivum L.cv.Hongdeng)果实采后病害的防治效果.酵母菌的使用浓度为1×108CFU/mL.结果表明,田间3种拮抗菌都能够在果实表面增值,但是只有C.laurentii和R.glutinis能够持续稳定地生长.C.laurentii的抑病效果最好,它对田间环境和采后低温低氧及高CO2都具有很强的适应能力.     

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit

AIMS: To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated. METHODS AND RESULTS: Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi. CONCLUSION: Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.     

山胡椒及其挥发物对马铃薯块茎蛾产卵选择的影响

【目的】为了确定山胡椒Lindera glauca(Sieb.Zuce)是否对马铃薯块茎蛾Phthorimaea operculella Zeller的产卵有驱避作用。【方法】利用选择性产卵试验方法在室内分别测定了山胡椒的完整果实、压碎果实、根以及不同浓度(0.25~4.0 g E/m L)的压碎山胡椒果实正己烷提取物对马铃薯块茎蛾产卵选择性的影响;在模拟仓库内测定了压碎的果实对其产卵的影响;进而在室内测定了柠檬醛、沉香醇、香叶醇和α-水芹烯不同浓度(0.00075~0.012 g/L)的溶液对其产卵选择性的影响。【结果】山胡椒完整果实、压碎果实、根在室内对马铃薯块茎蛾产卵具有驱避效果,其中压碎果实的产卵驱避效果最好,20 g压碎果实的产卵驱避率可达93.7%。山胡椒压碎果实正己烷提取物在0.5~4.0 g E/m L的浓度范围内随着浓度的升高,产卵驱避效果逐渐增强。在模拟仓库内20 g压碎的果实产卵驱避率是82.5%;0.003~0.012 g/L的柠檬醛,0.012 g/L沉香醇,0.00075~0.012 g/L的香叶醇,0.003~0.012 g/L的α-水芹烯对马铃薯块茎蛾产卵有显著的驱避效果。【结论】山胡椒及其挥发物对马铃薯块茎蛾产卵有驱避效果。     

短波紫外线照射对‘金都’火龙果采后保鲜的影响

以‘金都’火龙果(Hylocereus polyrhizus ‘Jindu’)果实为试材,采用波长254 nm紫外杀菌灯为辐射源,给予不同剂量短波紫外线(Ultraviolet-C,UV-C)照射处理,探讨低剂量UV-C对火龙果采后保鲜的影响及作用机理。结果表明,不同剂量UV-C照射处理能有效抑制‘金都’火龙果果实腐烂和电导率上升,降低果实TSS含量,其中1.0 kJ·m–2紫外线辐照效果最好。1.0 kJ·m–2 UV-C处理能极显著提高贮藏期火龙果的SOD和CAT活性,显著提高贮藏早中期的几丁质酶活性和PPO活性,β-1,3葡聚糖酶活性在贮藏后期也显著高于对照,但降低了火龙果贮藏中期(第6天)的POD活性。此外,1.0 kJ·m–2 UV-C处理显著提高火龙果贮藏期H2O2含量(除第6天外),对果实的失水率无影响。采后火龙果应用适当剂量UV-C照射可提高抗病性,延长贮藏保鲜期。     

Commercial techniques for preserving date palm (Phoenix dactylifera) fruit quality and safety: A review

The popularity of date palm (Phoenix dactylifera) fruit is increasing, therefore the demand for high-quality date palm fruit with less or no chemical treatment is the topic of interest for date producers and consumers. The quality of date palm fruit is much dependent on its postharvest handling and processing. For preventing the degradation and maintenance of the high quality of dates during the storage an appropriate harvest and post-harvest processes are required. The process should control the biotic and abiotic factors like insects, fungus, temperature, as well as handling and processing of dates. Therefore, in this work, we reviewed the literature related to the protection of date fruits during their post-harvest life. The commercially viable advance and updated techniques that can be used to avoid storage losses and problems while keeping fruit quality (nutritional, color, flavor, and texture) and microbial safety under optimal conditions are discussed.     

Genome-wide identification and expression analysis of the lipoxygenase gene family during peach fruit ripening under different postharvest treatments

In plants, lipoxygenase (LOX), facilitated by the LOX family genes is closely related to fruit ripening and senescence, but research on LOX in peach fruit is limited. To study the roles of LOX family genes in fruit ripening during storage, a comprehensive overview of the LOX gene family in peach is presented, including their phylogenetic relationships, gene structures and subcellular localizations. Additionally, the fruit quality, including fruit firmness, ethylene production and soluble solids content under different storage conditions, were assessed. Finally, 12 peach genes that encode LOX proteins have been identified, and comparisons of the PpaLOX gene expression levels under different postharvest treatments in peach fruit suggest that PpaLOX2.1, PpaLOX7.1, PpaLOX7.2, and especially PpaLOX2.2, may be required in peach fruit ripening during storage. The results will be useful to further analyze the functions of the LOX family of genes in plants.     

Timing of canopy closure influences carbon translocation and seed production of an understorey herb, Trillium apetalon (Trilliaceae)

BACKGROUND AND AIMS: The light availability on a temperate, deciduous-forest floor varies greatly, reflecting the seasonal leaf dynamics of the canopy trees. The growth and/or reproductive activity of understorey plants should be influenced by the length of the high-irradiance period from snowmelt to canopy closure. The aim of the present study was to clarify how spring-blooming species regulate the translocation of photosynthetic products to current reproduction and storage organs during a growing season in accordance with the changing light conditions. METHODS: Growth pattern, net photosynthetic rate, seed production, and shoot and flower production in the next year of Trillium apetalon were compared between natural and experimentally shaded conditions. Furthermore, translocation of current photosynthetic products within plants was assessed by a labelled carbon-chase experiment. KEY RESULTS: During the high-irradiance period, plants showed high photosynthetic ability, in which current products were initially used for shoot growth, then reserved in the rhizome. Carbon translocation to developing fruit occurred after canopy closure, but this was very small due to low photosynthetic rates under the darker conditions. The shading treatment in the early season advanced the time of carbon translocation to fruit, but reduced seed production in the current year and flower production of the next year. CONCLUSIONS: Carbon translocation to the storage organ had priority over seed production under high-irradiance conditions. A shortened bright period due to early canopy closure effectively restricts carbon assimilation, which greatly reduces subsequent reproductive output owing to low photosynthetic products for fruit development and small carbon storage for future reproduction. As populations of this species are maintained by seedling recruitment, acceleration of canopy closure timing may influence the maintenance and dynamics of populations.     

Ionizing irradiation quarantine treatment against oriental fruit moth (Lepidoptera: Tortricidae) in ambient and hypoxic atmospheres

Oriental fruit moth, Grapholita molesta (Busck), is a pest of many rosaceous temperate fruits, including pomes, Malus spp., and stone fruits, Prunus spp., in much of the world. However, some areas are free of the pest, and shipments of fruit hosts from infested to noninfested areas may be regulated. Current quarantine treatments for oriental fruit moth include methyl bromide fumigation and cold storage for several weeks. Methyl bromide use is being restricted because it is a stratospheric ozone-depleting substance, and alternatives are sought. Cold is not tolerated by many hosts of oriental fruit moth. The objective of this research was to develop irradiation quarantine treatments against the pest under ambient and hypoxic storage conditions because some hosts of oriental fruit moth are stored in hypoxic atmospheres, and hypoxia is known to lessen the effects of irradiation. In ambient atmospheres, no adults emerged from 58,779 fifth instars (the most radiotolerant stage present in fruit) irradiated with a target dose of 200 Gy (195-232 Gy measured). In atmospheres flushed with nitrogen, 5.3% of adults emerged from 44,050 fifth instars irradiated with a target dose of 200 Gy (194-230 Gy measured), but they died at a faster rate than control adults and without laying eggs. A dose of 232 Gy (the maximum recorded when 200 Gy was targeted) is recommended to disinfest any fruit of oriental fruit moth under ambient and hypoxic atmospheres.     

Use of Tissue Culture and Biotechnology for the Genetic Improvement of Watermelon

Watermelon is an important vegetable crop world-wide with over 81 million metric tons produced annually. Despite these high production figures, million of metric tons of fruit are lost in fields to disease. Genetic improvement through tissue culture and biotechnology offer potential routes of improving fruit harvest by offering higher quality products, like seedless fruit, or by introducing recombinant genes or generating somaclonal variants with improved resistance to biotic or abiotic stresses. The purpose of this review is to highlight how tissue culture and biotechnology have been used for the genetic improvement of watermelon and provide suggestions for future application of these methods to facilitate further genetic improvement.     

授粉对黄瓜果实发育和品质的影响

以 津绿 3号 黄瓜为试材 ,研究了授粉对黄瓜果实发育、营养成分变化及采后果形变化的影响 .结果表明 ,授粉可减少化瓜、刺激果实发育、提高果实商品性 ,并提高产量 ,其坐瓜率、商品瓜率、单瓜重及产量分别较单性结实提高 6 3.0 %、6 8.7%、2 2 .6 %和 12 7.6 % .授粉瓜和单性结实瓜均表现为随着果实发育 ,可溶性蛋白质和维生素 C含量呈减少的趋势 ,可溶性糖含量呈逐渐增长的趋势 ,游离氨基酸含量呈波动变化 ,但授粉瓜的 4种营养成分均高于单性结实瓜 .在采后 1～ 5 d,授粉瓜头部易膨大形成大头瓜 ,而单性结实瓜果形变化不大     

The structure of the fruit peel in two varieties of Malus domestica Borkh. (Rosaceae) before and after storage

The structure of fruit peel of two apple varieties ‘Szampion’ and ‘Jonagold’ was investigated using light microscopy as well as scanning and transmission electron microscopy. The samples were taken immediately after harvest and after 6-month controlled atmosphere storage. The Szampion and Jonagold fruit differed in terms of the surface type, number of lenticels, thickness of the cuticular epithelium, height of epidermal cells and thickness of the hypodermis as well as the amount of crystalline wax and the number of microcracks formed on the fruit surface. The 6-month storage resulted in fruit weight loss, increased numbers and depth of microcracks, thickening of the amorphous wax layer and enhanced production of platelet forms of crystalline wax, which filled the microcracks abundantly. Compared with Jonagold, the Szampion fruit exhibited a fewer lenticels, a bigger number of microcracks, smaller amounts of crystalline wax and more substantial weight loss. The apple varieties studied had a reticulate–lamellate cuticle, and at harvest, the epidermal and hypodermal cells contained numerous amyloplasts filled with starch grains, which were not found after the storage period. Additionally, after storage, the cell protoplasts in the apple peel displayed a disorganised structure, and their vacuoles contained fragments of cell membranes, intravacuolar precipitates and deposits, and spherical bodies. The results may facilitate better understanding of changes occurring in fruits of Szampion and Jonagold during storage and help choose the best storage conditions to reduce loss of weight and prevent impairment of fruit quality.     

Corn Residue Supply in the Irrigated Corn Belt

The present study quantifies the profit-maximizing supply of corn stover per unit of land under alternative crop rotations in irrigated cropland with and without limits to irrigation. The model is parameterized based on growing conditions in Nebraska, USA. Our analysis quantifies a trilemma between stover supply, groundwater consumption, and food/feed supply per unit of land. In the absence of water conservation policies, higher stover prices are associated with higher supply and increased irrigation application. If an upper limit is imposed on irrigation at the baseline level (for groundwater conservation purposes), an increase in net revenue from stover sale from $15 to $25/metric ton is associated with an increase in stover supply of 5 metric tons/ha and a 2-metric ton reduction in corn yield under continuous corn. Under corn/soybean rotation, such an increase in net revenue is associated with an increase in stover supply of 10 metric tons/ha, and reductions of 0.5 metric tons in corn yield and 0.7 metric tons in soybean yield.