外源5-氨基乙酰丙酸对设施番茄果实发育及糖酸品质的影响北大核心CSCD

番茄果实糖酸类物质的含量及比例直接影响其风味品质,前期研究表明,适宜浓度的外源5-氨基乙酰丙酸(ALA)能够促进果实的成熟并提高其芳香品质。该试验为探究外源ALA对番茄果实发育及其糖酸品质的影响,以番茄‘原味1号’(Solanum lycopersicum cv.Yuanwei No.1)品种为试材,于第4穗果授粉后10 d果实表面喷施0、100和200 mg·L^(-1)的ALA溶液,分析ALA对番茄果实形态、果皮色泽及果实不同部位组织中糖、酸类物质组分及含量的影响。结果表明:(1)外源ALA溶液能显著促进番茄果实横径、纵径的增加,提高果实单果重,还显著降低果实硬度,促进果实软化,提升果实口感,并提高了果实V_(C)和可溶性固形物含量。(2)果实不同部位组织(包括果肉、小柱和隔膜)糖类物质组分含量测定结果显示,外源ALA处理能够显著提高果实可溶性总糖含量(包括果糖、葡萄糖和蔗糖),并有利于糖类物质向果肉中积累。(3)在有机酸类物质中,除酒石酸含量增加外,外源ALA处理均能不同程度地降低果实各部位组织中酸类物质含量,从而显著提高番茄果实果肉部位糖酸比,提升果实糖酸品质。研究发现,在番茄果实发育过程中外源施用200 mg·L^(-1) ALA不仅能够促进果实发育及着色,提高单果重,提升果实的外观品质,还有利于果实糖酸品质的形成。     

Seasonal Evolution of the Quality of Fresh Glasshouse Tomatoes under Mediterranean Conditions, as Affected by Air Vapour Pressure Deficit and Plant Fruit Load

Changes in yield and quality of fresh tomatoes in response toair vapour pressure deficit (VPD) and plant fruit load werestudied under Mediterranean summer conditions. Plants thinnedto three or six fruits per truss were grown in two compartments,one at a VPD below 1.5 kPa, the other without VPD control. Theseasonal trend in fruit yield and quality was assessed fromApril to September by weekly measurement of number, fresh weightand dry matter content of harvested fruits, together with theoccurrence of blossom-end-rot (BER) and cracking. On two occasions,in July and September, sugar and acid content was measured atthree ripening stages. The seasonal decrease in fresh yieldwas attenuated at low VPD, because of higher individual fruitfresh weight, especially at low fruit load. Low VPD decreasedoccurrence of BER but like low fruit load, it increased fruitcracking. Fruit dry matter content was lower at low VPD, butwas unaffected by fruit load. Sugar content and the ratio ofsugars:acids was increased at high VPD and low fruit load, withinteractive effects depending on season and ripening stage.The influence of VPD on acid content differed with fruit loadand also changed during ripening and between seasons. Resultsshowed that water was the main limiting factor for growth offruits picked in July; at this time, reducing fruit load topromote mean fruit size had negative effects on BER and cracking.Reducing VPD reduced BER but had a negative effect on crackingand diluted both the dry matter and sugar content. For fruitsharvested later in summer, these negative effects were attenuatedbecause fruit growth was also carbon limited. Copyright 2000Annals of Botany Company Lycopersicon esculentum Mill., tomato, water and carbon stress, yield, quality, dry matter, sugar, acid, BER, volatile composition     

Regulation of tomato fruit ascorbate content is more highly dependent on fruit irradiance than leaf irradiance

Background and Aims

The mechanisms involving light control of vitamin C content in fruits are not yet fully understood. The present study aimed to evaluate the impact of fruit and leaf shading on ascorbate (AsA) accumulation in tomato fruit and to determine how fruit sugar content (as an AsA precursor) affected AsA content.

Methods

Cherry tomato plants were grown in a glasshouse. The control treatment (normally irradiated fruits and irradiated leaves) was compared with the whole-plant shading treatment and with leaf or fruit shading treatments in fruits harvested at breaker stage. In a second experiment, the correlation between sugars and AsA was studied during ripening.

Key Results

Fruit shading was the most effective treatment in reducing fruit AsA content. Under normal conditions, AsA and sugar content were correlated and increased with the ripening stage. Reducing fruit irradiance strongly decreased the reduced AsA content (−74 %), without affecting sugars, so that sugar and reduced AsA were no longer correlated. Leaf shading delayed fruit ripening: it increased the accumulation of oxidized AsA in green fruits (+98 %), whereas it decreased the reduced AsA content in orange fruits (−19 %), suggesting that fruit AsA metabolism also depends on leaf irradiance.

Conclusions

Under fruit shading only, the absence of a correlation between sugars and reduced AsA content indicated that fruit AsA content was not limited by leaf photosynthesis or sugar substrate, but strongly depended on fruit irradiance. Leaf shading most probably affected fruit AsA content by delaying fruit ripening, and suggested a complex regulation of AsA metabolism which depends on both fruit and leaf irradiance and fruit ripening stage.Key words: Ascorbate, fruit quality, irradiance, shading, Solanum lycopersicon, sugars, tomato, vitamin C     

Improved growth,productivity and quality of tomato (Solanum lycopersicum L.) plants through application of shikimic acid

A field experiment was conducted to investigate the effect of seed presoaking of shikimic acid (30, 60 and 120 ppm) on growth parameters, fruit productivity and quality, transpiration rate, photosynthetic pigments and some mineral nutrition contents of tomato plants. Shikimic acid at all concentrations significantly increased fresh and dry weights, fruit number, average fresh and dry fruit yield, vitamin C, lycopene, carotenoid contents, total acidity and fruit total soluble sugars of tomato plants when compared to control plants. Seed pretreatment with shikimic acid at various doses induces a significant increase in total leaf conductivity, transpiration rate and photosynthetic pigments (Chl. a, chl. b and carotenoids) of tomato plants. Furthermore, shikimic acid at various doses applied significantly increased the concentration of nitrogen, phosphorus and potassium in tomato leaves as compared to control non-treated tomato plants. Among all doses of shikimic acid treatment, it was found that 60 ppm treatment caused a marked increase in growth, fruit productivity and quality and most studied parameters of tomato plants when compared to other treatments. On the other hand, no significant differences were observed in total photosynthetic pigments, concentrations of nitrogen and potassium in leaves of tomato plants treated with 30 ppm of shikimic acid and control plants. According to these results, it could be suggested that shikimic acid used for seed soaking could be used for increasing growth, fruit productivity and quality of tomato plants growing under field conditions.     

Application of PSX biocontrol preparation confers root-knot nematode management and increased fruit quality in tomato under field conditions

PSX is a combination of biocontrol bacteria that can potentially prevent and control soil-borne diseases for a variety of crop cultivars. In this study, we investigated the utility of PSX in controlling root-knot nematodes in tomato under field conditions. The application of PSX reduced the severity of disease caused from Meloidogyne incognita by 63–69% and increased tomato yield by 31.5–39%. Furthermore, to investigate the effect of PSX treatment on tomato fruit quality, we quantified the soluble sugar, titratable acid, soluble solids, and vitamin C contents in fruit postharvest. We demonstrated that PSX treatment improved tomato fruit quality. Finally, we also showed that the total nitrogen (N), available N, potassium, and organic matter contents in the soil increased after PSX treatment. PSX is a promising biocontrol preparation that can provide beneficial effects to tomato growers, including biological control of root-knot disease, plant growth promotion, enhanced tomato fruit quality, and increased levels of organic fertilisers in the soil.     

The effects of Penicillium digitatum and Fusarium oxysporum rots on nutritional content of pawpaw (Carica papaya L.)

Investigations were carried out on the effects of Penicillium digitatum and Fusarium oxysporum on the nutritional value of pawpaw (Carica papaya). Decreases were observed in ash content, phosphorus, sodium, reducing sugars and ascorbic acid levels of fruits infected with P. digitatum, but increases in calcium and potassium content. In fruits infected by F. oxysporium, there were decreases in phosphorus, calcium, sodium ascorbic acid and reducing sugar levels; but the levels of ash content increased. The total protein level increased in the fruits infected with both fungi. These results revealed a reduction in fruit quality.     

Chemical and sensory characteristics of the fruits of eight cultivars of field grown tomato

The physical and sensory characteristics of tomato fruits (cf. Gajc-Wolska et al.: Physical and sensory characteristics of the fruits …, this issue) were supplemented by total sugars and titratable acid analysis and flavor. The instrumental and sensory methods were highly statistically correlated. Comparison of cultivars always requires that physical and chemical analysis of tomato fruit quality should always include results of sensory evaluation.     

沼液部分替代化肥在日光温室秋番茄上的应用效果

为探索沼液和化肥协同促生的效果,以3种常见禽畜粪便(鸭粪、猪粪、牛粪)作为发酵原料的沼液为母液,以氮磷钾镁肥作为化学肥料辅助,平衡不同稀释比例之间的养分差异,研究沼液配施对番茄生长发育的影响. 结果表明: 沼液部分替代化肥可以显著改善土壤速效氮、磷、钾的肥力状况,依发酵原料和稀释比例不同,沼液对土壤水溶性钙、镁和有效铁、锰、铜、锌有不同程度的活化作用. 与完全施用化肥相比,沼液配施化肥可显著促进番茄生长,且随生育期的延长,沼液的促生作用愈发凸显,最终增产幅度达55.9%～232.8%,化肥用量减少18.2%～85.0%;番茄果实品质显著改善,番茄红素、Vc、总糖含量均显著提高,果实酸度显著降低,NO₂^-降幅达35.6%～90.3%,而口感得分比化肥处理高出7.0%～20.3%.相关分析发现,番茄产量和品质呈非线性关系,口感与糖酸比呈显著正相关,番茄果实口感受肥料种类的影响亦显著. 总之,沼液配施化肥用于番茄生产可以实现高产、优质、环保、培肥和资源高效利用的目的.     

Phenotypic and fine genetic characterization of the D locus controlling fruit acidity in peach

Background  

Acidity is an essential component of the organoleptic quality of fleshy fruits. However, in these fruits, the physiological and molecular mechanisms that control fruit acidity remain unclear. In peach the D locus controls fruit acidity; low-acidity is determined by the dominant allele. Using a peach progeny of 208 F₂ trees, the D locus was mapped to the proximal end of linkage group 5 and co-localized with major QTLs involved in the control of fruit pH, titratable acidity and organic acid concentration and small QTLs for sugar concentration. To investigate the molecular basis of fruit acidity in peach we initiated the map-based cloning of the D locus.     

Improved functional and nutritional properties of tomato fruit during cold storage

The use of synthetic antioxidants has been associated with serious concerns for human and environmental health. During ripening stages, tomato fruit is exposed to different abiotic stresses which not only influence its nutritional, mechanical, and functional properties at harvest, but also affect the quality and shelf life of the fruit during storage. This study investigated the pattern of changes in dietary antioxidants during various ripening stages of tomato fruit (cv. Red Rose) and their impact on storage behavior of the fruit during cold storage. Tomato fruits were harvested at mature green, breaker, turning, pink, light-red and red stages of maturity. Then, they were analysed for flesh firmness, soluble solids content, titratable acidity, total sugars, pH, dry matter content, lipophilic (lycopene, β-carotene, and total carotenoids), and hydrophilic (ascorbic acid, phenolic and flavonoids) antioxidants. Additional fruits were harvested at each maturity stage and divided into three equal lots, then were subjected to low-temperature (10 ± 1 °C) storage with 80 ± 5% RH, for 7, 14, and 21 days. Flesh firmness, and the levels of dietary antioxidants were analysed following the subsequent storage periods. The results revealed that the peak of hydrophilic antioxidants such as ascorbic acid, phenolic compounds, and flavonoids was between the ‘pink’ and the ‘light-red’ stages of fruit maturity. Whereas tomatoes harvested at the ‘red’ stage of maturity had the highest levels of lycopene and β-carotene. Both the stage of fruit maturity at harvest and duration of cold storage influenced flesh firmness, organoleptic and functional properties of ‘Red Rose’ tomato fruit. In conclusion, the results of the current investigation have practical implications in formulating foods with improved functional properties at processing industries.     

The effect of nitrogen and phosphorus deficiency on flavonol accumulation in plant tissues

The flavonol content of Arabidopsis thaliana and tomato seedlings was assessed in conditions of reduced nitrogen or phosphorus availability. In both systems, a significant inverse relationship was observed between nutrient availability and flavonol accumulation, with nitrogen limitation promoting the greatest increase in flavonols. A trial was established to determine the effects of decreased nitrogen and phosphorus availability on the flavonol content of leaf and fruit tissues of tomato plants (Lycopersicon esculentum cv. Chaser) in a commercial situation. Nutrients were supplied by a hydroponic system with nutrient regimes designed to provide the highest and lowest nitrogen and phosphorus levels with which it is possible to support plant growth and fruit set. Fruiting was abundant and tomato fruits were harvested at mature green, breaker and red stages of ripening; leaves were also harvested from the tops of the plants. All tissues were analysed for flavonol content using reversed‐phase high‐performance liquid chromatography. Flavonol accumulation in the leaves of mature tomato plants was found to increase significantly in response to nitrogen stress, whereas phosphorus deficiency did not elicit this response. Reduced nitrogen availability had no consistent effect on the flavonol content of tomato fruits. Phosphorus deficiency elicited an increase in flavonol content in early stages of ripening. Effects of nutrient stress on the flavonol content of tomato fruits were lost as ripening progressed. The findings suggest that nutrient status may be employed to manipulate the flavonol content of vegetative tissues but cannot be used to elevate the flavonol content of tomato fruit.     

Response of Tomato Sugar and Acid Metabolism and Fruit Quality under Different High Temperature and Relative Humidity Conditions

The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture. However, there is little information about the precise interaction between them on tomato fruit quality. The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits, and to determine the best relative air humidity for fruit quality under high temperature environments. Four temperature treatments (32°C, 35°C, 38°C, 41°C), three relative air humidity (50%, 70%, 90%) and four duration (3, 6, 9, 12 d) orthogonal experiments were conducted, with 28°C, 50% as control. The results showed that under high temperature and relative air humidity, the activity of sucrose metabolizing enzymes in young tomato fruits changed, which reduced fruits soluble sugar content; in addition, enzyme activities involved phosphopyruvate carboxylase (PEPC), mitochondria aconitase (MDH) and citrate synthetase (CS) increased which increased the content of organic acids (especially malic acid). Eventually, vitamin C, total sugar and sugar-acid ratio decreased significantly, while the titratable acid increased, resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit. Specifically, a temperature of 32°C and a relative air humidity of 70% were the best cultivation conditions for tomato reproductive growth period under high temperature. Our results indicating that fruit quality reduced under high temperature at the flowering stage, while increasing the relative air humidity to 70% could alleviate this negative effect. Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.     

成串采收对番茄果实采后乙烯合成及贮藏品质的影响

为研究成串采收对番茄果实采后乙烯合成及贮藏品质的影响,对广西田阳县两个栽培区两种嫁接砧木的串收番茄的采后生理指标进行测定,探讨了该采收方式对番茄果实采后保鲜的作用机制。结果表明:整个贮藏期,不同栽培区不同嫁接砧木的番茄成串采收的果实,乙烯生成量明显低于对照的常规单果采收。其中,砧木1号Ⅰ区的串收番茄的乙烯生成量,采后5 d即下降至最低点(0.35 nL·g~(-1)·h~(-1)),显著低于其对照(1.36 nL·g~(-1)·h~(-1)),其他栽培区和砧木组合的串收番茄,在采后15 d乙烯生成量达到最低值。串收番茄的类胡萝卜素、番茄红素和抗坏血酸等果实内天然抗氧化物质的含量,在贮藏前期快速升高,且峰值显著高于对照。此外,成串采收处理还一定程度抑制了果实后熟阶段可溶性糖的积累和可滴定酸的分解。因此,番茄成串采收处理,可能通过抑制果实采后乙烯的合成,同时提高类胡萝卜素、番茄红素和抗坏血酸的水平,并且推迟糖和酸等营养物质的后熟变化进程,实现其延长果实货架期,提高商品品质的作用。     

Improved yielding and reduced puffiness under extreme temperatures induced by fruit-specific expression of <Emphasis Type="Italic">rolB</Emphasis> in processing tomatoes

Tomato fruit production is severely hampered by both extremely high and low temperatures, mainly due to impaired microsporogenesis and pollination under these conditions. Even mild temperature stress, leading to partial damage to pollen viability can result in the production of under-fertilized puffy fruits of poor quality, while severe stress can abolish fruit set completely. Genetic or transgenic parthenocarpy that enables fertilization-independent fruit development offers a solution for tomato yielding under conditions unfavorable for pollen production and/or fertilization. A transgenic processing tomato UC82 line, expressing rolB specifically during early stages of fruit development was compared to the parental line with respect to yield and fruit quality under extreme temperatures. Under both high and low temperatures the transgenic line performed significantly better than the parental line. Its yield was significantly higher mainly due to a higher number of fruits that did develop, and also because of increased fruit weight. While the UC82 fruits developed under high temperatures were very puffy and severely malformed, the transgenic fruits maintained improved jelly fill and were of smooth and regular shape. Interestingly, under high temperatures the improved jelly fill in the transgenic line was accompanied by a higher number of seeds, suggesting that not only the developing seeds promote development of the placental tissue but also that proliferation of this tissue supports better seed development.     

不同供氮水平下施硅对辣椒产量与营养品质及其养分吸收利用的影响

为探究不同供氮水平下施硅对辣椒产量、果实品质及养分吸收利用的影响，以辣椒品种‘奥黛丽’为试验材料，采用基质栽培，设置正常施氮肥（1.0N：260.9 kg/667 m2）、氮肥减施40%（0.6N：149.1 kg/667 m2）、氮肥减施60%（0.4N：104.3 kg/667 m2）、不施氮肥（0N：0 kg/667 m2）4个不同供氮（基施）水平和2个硅肥（根施）水平（0 mmol/L、1.5 mmol/L），研究不同供氮水平下硅对辣椒产量、品质及氮肥利用效率的影响效应，并筛选出最佳施肥处理，旨在为辣椒的增产提质提供理论基础和技术参考。结果表明：（1）0.6N供氮水平较1.0N、0.4N和0N供氮水平下的辣椒果实产量分别提高了7.18%、74.14%和87.99%，施硅处理后则进一步促进了果实产量，其中0.6N供氮水平下施硅较正常供氮量下的辣椒果实产量提高了15.33%；（2）0.6N供氮水平更有利于促进辣椒果实中可溶性糖、还原糖、可溶性蛋白、维生素C含量的提高和可滴定酸、NO3?含量的降低，施硅后不同供氮水平下辣椒果实品质均显著提高；（3）0.6N供氮水平更有利于辣椒果实矿质元素的积累与土壤氮肥利用率的提高，其中0.6N供氮水平较1.0N供氮水平下的氮肥利用率与氮肥农学效率分别显著提高了97.57%和69.20%，施硅处理后不同供氮水平下辣椒果实矿质元素含量与土壤氮肥利用率均显著提高；（4）通过对辣椒产量及果实品质指标的主成分分析，结果表明，0.6N+Si处理下的综合得分最高，即氮肥减施40%配施1.5 mmol/L的外源硅肥对辣椒产量、品质及氮肥的吸收利用促进效果最佳。     

Effect of postharvest salicylic acid treatment on fungal decay and some postharvest quality factors of kiwi fruit

The effect of salicylic acid (SA) treatment at different concentrations on fungal decay and some quality factors of kiwi fruit (Actinidia deliciosa var. Hayward) in postharvest conditions were studied. Results experiment showed that SA at all applied concentrations inhibited grey mould growth. The SA application significantly decreased weight loss percentage and increased life storage fruits. Also, SA positively affected on postharvest quality factors including total soluble solids (TSS), titratable acidity (TA), antioxidant, ascorbic acid and pH value. It was observed that treated fruits with SA at concentration 5?mM had the highest TSS, TA, ascorbic acid and antioxidant content and it had the lowest decay and acidity. Thus, these results showed that SA has strong impact on postharvest decay and fruit quality of kiwi fruit.     

Effects of the Lycopersicon chmielewskii sucrose accumulator gene (sucr) on fruit yield and quality parameters following introgression into tomato

A gene controlling fruit sucrose accumulation, sucr, was introgressed from the wild tomato species Lycopersicon chmielewskii into the genetic background of a hexose-accumulating cultivated tomato, L. esculentum. During introgression, the size of the L. chmielewskii chromosomal segment containing sucr was reduced by selection for recombination between RFLP markers for the sucr gene and flanking loci. The effects of sucr on soluble solids content, fruit size, yield and other fruit parameters were studied in the genetic background of the processing tomato cultivar Huntl00. In a segregating BC₅F₂ generation, the smallest introgression containing sucr-associated markers was necessary and sufficient to confer high-level sucrose accumulation, the effects of which were completely recessive. Fruit of sucr/sucr genotypes were smaller than those of +/sucr or +/+ genotypes at all stages of development. The timing of sugar accumulation and total sugar concentration were unaffected by sugar composition. No differences in total fruit biomass (fresh weight of red and green fruit) at harvest were observed between the genotypes, and sucrose accumulators produced greater numbers of fruit than hexose accumulators in one family. However, the proportion of ripe fruit at harvest, and hence yield of ripe fruit, as well as average ripe fruit weight and seed set were reduced in sucr/sucr genotypes. Sucrose accumulation was also associated with increased soluble solids content, consistency, serum viscosity, predicted paste yield and acidity, and decreased color rating. In the first backcross to L. chmielewskii, hexose accumulators (+/sucr) had larger fruit than sucrose accumulators (sucr/sucr), while no difference in soluble solids was detected.     

Effects of exogenous quercetin on the levels of carbohydrates and amino acids in fruits ofLycopersicon esculentum

Low doses of the exogenous flavonoid quercetin increased the content of sugars in tomato fruits of various cultivars. The content of glucose in tomato fruits of cv.Ukrainskii teplichnyi increased from 3.62 to 11.24% per unit dry weight. Increases in the content of glucose were found in all tomato cultivars examined. An analysis of qualitative and quantitative compositions of amino acids showed that their levels were markedly decreased in fruits of quercetin-treated plants. Our studies and data found in the literature suggest that this effect is due to the synthesis of sugars from amino acids by gluconeogenesis. The reverse process of sugar hydrolysis does not occur because exogenous quercetin inhibits the activity of pyruvate kinase.     

Contrasted responses to carbohydrate limitation in tomato fruit at two stages of development

The metabolic consequences of long‐term carbohydrate depletion have been well documented in many sink organs but not extensively in fruit. Therefore, in the present study the response to sugar limitation in tomato fruit (Lycopersicon esculentum Mill.) was investigated at two developmental stages; during the cell division and cell expansion phases. First, the response in excised fruit cultured in vitro was characterized. Sugar depletion caused an arrest of growth and an exhaustion of carbon reserves. The proteins that were degraded and the nitrogen released was transiently stored as asparagine and glutamine in both developmental stages and also as γ ‐aminobutyric acid (GABA) in expanding fruit. Fruit at the cell division stage appeared to be more sensitive to sugar limitation. The response to sugar depletion was then characterized in fruit from plants submitted to extended darkness. In planta, the effects of sugar‐limitation were similar to those described in vitro but much more attenuated, especially in expanding fruit, which still accumulated dry matter. The expression of cell cycle genes, sugar‐ and nitrogen‐related genes was reduced by darkness. Only asparagine synthetase gene expression was induced in both dark‐treated fruit. Together the present data revealed that the effects of the carbon limitation are more pronounced in the youngest fruits as it is probably controlled by the relative sink strength of the fruit.