A chromosome-level genome assembly for Chinese plum‘Wushancuili'reveals the molecular basis of its fruit color and susceptibility to rain-cracking

Chinese plum(Prunus salicina Lindl.)originates from China and makes a large contribution to the global production of plums.The P.salicina‘Wushancuili'has a green coloration and high fruit quality and is economically important in eliminating poverty and protecting ecology in the Yangtze River Three Gorges Reservoir.However,rain-induced cracking(rain-cracking,literally skin cracking caused by rain)is a limitation to‘Wushancuili'fruit production and causes severe losses.This study reported a high-quality‘Wushancuili'genome assembly consisting of a 302.17-Mb sequence with eight pseudo-chromosomes and a contig N50 of 23.59 Mb through the combination of Illumina sequencing,Pacific Biosciences HiFiⅢsequencing,and high-throughput chromosome conformation capture technology.A total of 25109 protein-coding genes are predicted and 54.17%of the genome is composed of repetitive sequences.‘Wushancuili'underwent a remarkable orthoselection during evolution.Gene identification revealed that loss-of-function in four core MYB10 genes results in the anthocyanin deficiency and absence of red color,revealing the green coloration due to the residual high chlorophyll in fruit skin.Besides,the occurrence of cracking is assumed to be closely associated with cell wall modification and frequently rain-induced pathogen enrichment through transcriptomic analysis.The loss of MYB10 genes might render fruit more susceptible to pathogen-mediated cracking by weakening the epidermal strength and reactive oxygen species(ROS)scavenging.Our findings provided fundamental knowledge regarding fruit coloration and rain-cracking and will facilitate genetic improvement and cultivation management in Chinese plums.

Pre-harvest fruit bagging influences fruit color and quality of apple cv. Delicious

An attempt was made to observe the effect of pre-harvest bagging with spun-bound fabric bags on color and quality of Delicious apple. Bagging was done about a month before harvesting and removed 3-day before harvesting. Bagged and non-bagged fruits were stored at 2℃ ± 1℃ and 90%-95% RH. Observations were recorded on color and fruit quality attributes such as total phenolics, AOX activity, fruit Ca contents, LOX activity, SSC and ascorbic acid contents at harvest and during storage. Our studies have revealed that bagged fruits have better color development (Hunter “a” = 52) than non-bagged fruits at harvest (Hunter “a” = 38), which declined slightly during storage. Similarly, at harvest, bagged fruits contained high amounts of Ca (5.38 mg/100g) and total phenolics (9.3 mg GAE/100gpulp) exhibited higher AOX activity (12.6 μmoles Trolox g-1), and had better SSC and ascorbic acid contents than non-bagged fruits, and there was a decline in all recorded parameters during storage. Bagged fruits exhibited lower LOX activity (1.38 μmoles min-1 g-1 FW) at harvest than non-bagged fruits (2.14 μmoles min-1 g-1 FW), indicating that non-bagged fruits were more senescent than bagged fruits. Further, LOX activity increased during storage both in bagged and non-bagged apples but increase in LOX activity was slower in bagged apples than in non-bagged apples.

A novel histone methyltransferase gene Cg SDG40 positively regulates carotenoid biosynthesis during citrus fruit ripening

The flesh color of pummelo(Citrus maxima)fruits is highly diverse and largely depends on the level of carotenoids,which are beneficial to human health.It is vital to investigate the regulatory network of carotenoid biosynthesis to improve the carotenoid content in pummelo.However,the molecular mechanism underlying carotenoid accumulation in pummelo is not fully understood.In this study,we identified a novel histone methyltransferase gene,CgSDG40,involved in carotenoid regulation by analyzing the flesh transcriptome of typical white-fleshed pummelo,red-fleshed pummelo and extreme-colored F1 hybrids from a segregated pummelo population.Expression of CgSDG40 corresponded to flesh color change and was highly coexpressed with CgPSY1.Interestingly,CgSDG40 and CgPSY1 are located physically adjacent to each other on the chromosome in opposite directions,sharing a partially overlapping promoter region.Subcellular localization analysis indicated that CgSDG40 localizes to the nucleus.Overexpression of CgSDG40 significantly increased the total carotenoid content in citrus calli relative to that in wild type.In addition,expression of CgPSY1 was significantly activated in overexpression lines relative to wild type.Taken together,our findings reveal a novel histone methyltransferase regulator,CgSDG40,involved in the regulation of carotenoid biosynthesis in citrus and provide new strategies for molecular design breeding and genetic improvement of fruit color and nutritional quality.

Insights into flavonoid biosynthesis during cucumber fruit peel coloration based on metabolite profiling and transcriptome analyses

The fruit peel color is a crucial trait of cucumber.To better understand the molecular mechanisms underlying cucumber peel coloration,we compared the UPLC-ESI-MS/MS-based flavonoid metabolomic and RNA sequencing-based transcriptomic profiling of the brown peeled cucumber line‘PW’at six developmental stages.A total of 210 flavonoid metabolites were identified.Of which,117 flavonoid metabolites were differentially accumulated.In this study,weighted gene co-expression network analysis combined with Kyoto Encyclopedia of Gene and Genomes enrichment analysis revealed key genes coding for seven enzymes and eight transcription factors(TFs)associated with flavonoid biosynthesis.Among them,the R2R3MYB CsaV3_4G001130 is the best candidate gene that is responsible for controlling mature fruit colors in cucumber.Sanger sequencing revealed one nonsynonymous SNP in the exon of CsaV3_4G001130 among the selected 11 cucumber lines,which introduced a premature stop codon,generating a truncated protein in pale yellow or creamy peeled fruits.Yeast two-hybrid assays showed a direct interaction of CsaV3_4G001130 with the bHLH TF CsaV3_1G002260 and the WD40 protein CsaV3_5G001800.However,the interactions were influenced by the nonsynonymous SNP we identified.Our finding revealed that the integrated transcriptome and metabolome analysis further demonstrated that the abundance of some pigmented flavonoids(especially anthocyanins and chalcones)contributed to the coloration of‘PW’fruits.These findings pave the way for elucidation of flavonoid biosynthesis and improvement of cucumber peel color in the future.

Inter-specific and intra-specific variability in fruit color preference in two species of Turdus

One of the main hypotheses proposed to explain the evolution of fruit color deals with a preference of avian frugivores for specific colors,mainly black and red,which are the most common fruit colors in many of the studied habitats.I analyzed fruit color preferences by wild birds belonging to 2 species of the highly frugivorous genus Turdus(Eurasian Blackbird Turdus merula Linnaeus,1758 and Redwing Turdus iliacus Linnaeus,1758)by means of captivity experiments with artificial fruits.Despite important within-individual(i.e.temporal)and among-individual variability,consistent patterns of species-specific color preferences emerged.Eurasian Blackbirds tended to prefer red over blue,green and black,whereas Redwings seemed to prefer black over the rest.Green was systematically avoided by both species,suggesting that it might signal unripeness of fruits.Both preferred colors have been previously reported as the most common among fleshy-fruited plants.The high variability,both within and between individuals,in preferences suggests that they can be subject to changes through experience and learning and,therefore,are not likely to drive the evolution of fruit color.The main differences between both species could be related to the most common fruit color they fed upon during the last months before capture.

Genetic diversity and offspring fitness in the red and white fruit color morphs of the wild strawberry Fragaria pentaphylla

Aims Fruit color polymorphisms are widespread in plants,but what maintains them is largely unclear.One hypothesis is that some morphs are preferred by dispersers while others have higher pre-or postdispersal fitness.This leads to the prediction that fruit color morphs will differ in pre-or postdispersal fitness.Methods We compared genetic and clonal diversity,mating system,morphological traits that might be associated with resistance to freezing,and germination,survival and seed production of progeny of the red and white fruit morphs in a population of a diploid,wild strawberry,Fragaria pentaphylla,from south-central China.Important Findings The red morph was much more abundant than the white but did not show higher genetic diversity as measured by observed and effective numbers of alleles,Shannon information index,or expected or observed heterozygosities.AMOVA showed that most of the genetic variation in the population was within rather than between morphs.Morphs did not differ in mating system parameters,and no significant biparental inbreeding was found in either morph.Gene flow between two morphs was high(N_(m)=6.89).Seeds of the red morph germinated about 2 days earlier and had a 40%higher rate of germination than those of the white morph,but survival of seedlings and seed production by surviving offspring did not differ between morphs.The whole postdispersal fitness of the red morph was about two times higher than that of the white morph.Red morphs had hairier petioles but not more surface wax on leaves.Overall,results showed partial evidence for difference in pre-and postdispersal fitness between fruit color morphs in F.pentaphylla.Differences in fitness independent of dispersal may thus partially account for fruit color polymorphism in all cases.

Reduction in Activity/Gene Expression of Anthocyanin Degradation Enzymes in Lychee Pericarp is Responsible for the Color Protection of the Fruit by Heat and Acid Treatment

Heat and acid treatments were reported to be a promising substitute for SO2 fumigation in color protection of postharvest lychee （Litchi chinensis） fruits, but the mechanism was not clear. In the present study, hot water （70℃） dipping followed by immersion in 2% HC1 （heat-acid） substantially protected the red color of the fruit during storage at 25℃ and inhibited anthocyanin degradation while hot water dipping alone （heat） led to rapidly browning and about 90% loss in anthocyanin content. The pH values in the pericarp of the heat-acid treated fruit dropped to 3.2, while the values maintained around 5.0 in the heat-treated and control fruit. No significantly different pH values were detected among the arils of heat-acid, heat treated and control fruit. Heat-acid treatment dramatically reduced the activities of anthocyanin degradation enzyme （ADE）, peroxidase （POD） and polyphenol oxidase in the pericarp. A marked reduction in LcPOD gene expression was also detected in heat-acid treated fruit, in contrast, induction was found in heat treated fruit. The pericarp of heat-acid treated fruit exhibited significantly lower respiration rate but faster water loss than that of the untreated or heat treated fruit. Taken together, heat treatment triggered quick browning and anthocyanin loss in lychee fruit, while heat-acid treatment protected the fruit color by a great reduction in the activities/gene expression of anthocyanin degradation enzymes and acidification of lychee pericarp.

氯吡苯脲对贵妃杧果果实产量、品质和采后贮运特性的影响

氯吡苯脲(forchlorfenuron,CPPU)是杧果生产上使用的膨大剂,由于使用不规范,造成了品质下降、果实畸形等诸多问题。本研究选用12 a树龄的贵妃杧果树为试材,在盛花期后15 d,喷施不同质量浓度(10、20、60 mg/L)的CPPU,花后15、25、35d各喷1次,共喷3次,生理成熟期后采摘,研究CPPU对贵妃杧果果实产量、品质和采后贮运特性的影响。结果表明:幼果期经10~20 mg/L CPPU处理后能够增加杧果的果形指数、促进果实膨大和产量增加,当CPPU浓度增加至60 mg/L时,果实膨大明显,但会导致产量下降。CPPU处理后,果实采摘时(生理成熟期)果实的叶绿素、类红萝卜素含量明显升高,花色苷明显降低,果皮红度值(a^(*))偏小,其颜色偏绿;完熟期杧果的叶绿素、类红萝卜素含量高,花色苷含量低,高浓度CPPU处理果实果面红色偏少,黄色偏多,果皮a^(*)值偏小,部分果实偏绿色;完熟期的可溶性固形物含量降低,总酸增加,固酸比下降,口感甜度下降,低浓度影响较小,高浓度CPPU处理对内在影响较大。CPPU处理可降低杧果采后病害的发生,果实采后保持较高的硬度,明显延缓杧果储藏期果实软化,明显延长了杧果的贮藏时间,提高了其采后贮运特性。综合以上结论,幼果期喷施CPPU的适宜浓度为10~20 mg/L,盛花期后15~50d果实细胞旺盛分裂期效果最佳,可显著增加单果重和产量,对果实品质和果实转色影响不显著,并能延长贮藏时间,更利于采后贮运保鲜。

辣椒类胡萝卜素生物合成的分子遗传学研究进展

辣椒(Capsicumspp.)属于茄科辣椒属,作为一种蔬菜和香料作物在世界各地得到广泛栽培。除作为烹饪食材和香料应用外,辣椒在制药和化妆品领域也有广泛的用途。类胡萝卜素是一类天然色素的总称,参与植物许多重要的代谢过程,如光合作用、光保护、光形态建成和生长发育等。类胡萝卜素具有多种生物活性,是辣椒果实主要的营养物质之一,培育类胡萝卜素含量更高的辣椒品种需要全面深入了解其生物合成及其调控的分子机制。分子生物学和生物技术的发展促进了类胡萝卜素生物合成基因的鉴定,为培育类胡萝卜素含量更高的辣椒新品种提供了机会。该文描述了类胡萝卜素的生理作用、类胡萝卜素与辣椒果实颜色、类胡萝卜素生物合成途径、辣椒类胡萝卜素生物合成途径的结构基因及调控因子、辣椒果实颜色的分子遗传学及与辣椒果实颜色有关的QTL位点等方面的研究进展。牻牛儿基牻牛儿基焦磷酸合成酶(GGPS)、八氢番茄红素合成酶(PSY)、八氢番茄红素脱氢酶(PDS)、ζ-胡萝卜素去饱和酶(ZDS)、番茄红素环化酶(LCY)、辣椒红素-辣椒玉红素合成酶(CCS)等是辣椒类胡萝卜素生物合成通路的端口酶和限速酶,其表达丰度和活性高低直接调控辣椒体内类胡萝卜素的含量。MYB306、DIVARICATA1、BBX20等转录因子参与辣椒类胡萝卜素生物合成的调控。类胡萝卜素生物合成和调控基因的多样性决定类胡萝卜素单体的数量和含量,影响辣椒果实呈现的颜色。基于目前研究进展,该文对未来辣椒类胡萝卜素代谢研究进行了展望,以期为今后培育富含类胡萝卜素的生物强化型辣椒新品种提供新思路。

喷施石硫合剂对促进沃柑果实着色的影响

为验证喷施石硫合剂对沃柑果实着色的效果,在广西南宁市武鸣区城厢镇开展石硫合剂不同处理的试验。结果表明,在沃柑成熟转色关键期(12月30日)喷施石硫合剂对促进沃柑转红和着色有显著促进作用,对促进转红和着色效果最显著的均是单次喷施石硫合剂1.2波美度,红度值a*比对照(CK)提升了15.24%,柑橘综合着色指数CCI比CK提升了40.07%,均达极显著差异水平。单次喷施石硫合剂0.8波美度,a*和CCI分别比CK提升了11.67%和32.31%。所有喷施石硫合剂的处理均表现出对转红和着色有提升效果。经过田间观察,石硫合剂还对溃疡病、灰霉病、蚜虫、蓟马、蚧壳虫、红蜘蛛等病虫害有良好防效。

“环境影响番茄果实色泽变化”实验的PBL教学实践

运用问题导向学习(PBL)教学方法,以番茄果实着色不均的品质问题为教学实验切入点,引导学生查阅文献解析影响果实品质的环境因子,鼓励学生基于文献查阅结果提出合理设想。根据实验假设,教师引导学生设计不同温度及光照强度组合的多因子实验。通过果实表型观察、叶绿素/番茄红素含量测定、果实硬度分析及荧光定量PCR检测基因表达等植物生理学综合性实验,逐步引导学生发现高温通过抑制番茄红素关键基因的表达抑制番茄红素的合成,从而导致果实着色不均的机理。通过实验,学生能切实感受农业生产与科学研究的紧密联系,体会理论指导实践的重要意义。因此,PBL法结合农业生产实际问题设计的教学实践对培养学生专业知识的综合应用、训练学生的科学思维及创新研究能力具有重要作用。

3个红梨品种在湖南的引种观察

对引入湖南省浏阳的3个红梨品种美人酥、红酥脆与满天红进行了生长结果习性、适应性以及果实品质的观察比较。结果表明,3个红梨品种在浏阳地区均能正常完成年生长周期,美人酥与满天红生长旺,坐果稳,盛果期树666.7 m 2产量1400 kg,红酥脆长势稍弱,产量1200 kg。3个红梨品种着色均不稳定,果皮锈斑较严重,对着色影响大,以满天红着色相对较好,美人酥次之,红酥脆较差。3个红梨品种均在9月中旬前后成熟,单果重300 g以上,肉质细,石细胞少。可溶性固形物含量13.0%~13.8%,可溶性糖含量9.05%~9.36%,均以美人酥含量最高,其次为满天红、红酥脆。总酸含量1.13~1.42 g/kg,以满天红最高,美人酥与红酥脆相近。综合分析认为,3个品种均不适宜在湖南地区大面积发展。

9个粉(白)果草莓品种在贵州贵阳栽培比较试验

为筛选出适宜贵州省贵阳地区栽培的粉、白果草莓品种,丰富贵阳地区栽培草莓品种结构,促进贵阳地区草莓产业发展。以9个粉、白果草莓品种为试材,观察物候期,测定植株生长指标及果实品质、产量,比较不同品种在贵阳地区的栽培表现。结果表明:粉玉产量高,硬度最大,可溶性固形物含量高,风味酸甜可口,有香气,口感佳;小白果实成熟期最早,可溶性固形物、可滴定酸含量最高,有香气,风味浓郁酸甜;淡雪果面粉色,果肉浅粉色,可溶性固形物含量、固酸比较高,白粉病病果率低。根据产量、可溶性固形物含量、固酸比、白粉病病果率4个性状的加权得分建立草莓品种筛选标准,筛选出在贵阳地区具有推广前景的草莓品种有粉玉、小白、淡雪。

不同果肉颜色欧李果实酚类物质的变化及其抗氧化活性研究

【目的】探讨3种不同果肉颜色欧李果实中酚类物质含量及其抗氧化活性,为欧李的进一步研究和应用提供依据。【方法】选果皮果肉色泽不同的具有代表性的3种蒙原欧李资源类型(红皮深红肉、红皮黄肉、红皮浅红肉),分别选择1个代表性资源为材料,研究果实发育过程(幼果期、硬核前期、硬核后期、着色膨大期、硬熟期、完熟期)及采后贮藏过程(0~40 d)中总酚、总黄酮、原花青素及花青素含量的变化规律,测定完熟期果实色度值(亮度值L*、红绿值a*、黄蓝值b*),比较硬熟期和完熟期3种类型欧李果实中4种酚类物质的总抗氧化能力、铁离子还原力、DPPH·清除率及·OH清除率,分析酚类物质含量与其抗氧化活性之间的相关性。【结果】3种类型欧李果实中,果皮色度值表现为红皮黄肉L*、a*、b*均最高,红皮深红肉b*最低;果肉色度值表现为红皮黄肉L*、b*最高,a*最低,红皮深红肉a*最高,红皮浅红肉b*最低。在欧李果实发育过程中,3种类型果实中总酚、总黄酮及原花青素含量整体均表现为先升高后降低,花青素含量呈逐渐增加的趋势;在采后贮藏过程中,3种类型欧李果实总酚、总黄酮、原花青素含量整体表现为先升高后降低再升高。不同类型欧李果实中4种酚类物质含量均有差异,其中总酚、总黄酮及原花青素含量基本表现为红皮黄肉果实最高,红皮深红肉次之,红皮浅红肉最低;花青素含量则表现为红皮深红肉明显高于其他2种类型。3种类型欧李硬熟期和完熟期果实4种酚类物质的总抗氧化能力、铁离子还原力、DPPH·清除率及·OH清除率均表现为总酚最高,其次为总黄酮和原花青素,花青素最低;不同类型果实的抗氧化活性表现不一。3种类型欧李果实的各酚类物质含量与其抗氧化活性均具有正相关关系,其中与总抗氧化能力、铁离子还原力和DPPH·清除率的相关性均较高,与·OH清除率的相关性较低。【结论】在发育及采后贮藏过程中,不同类型欧李果实中总酚、总黄酮及原花青素含量变化一致,花青素含量与之不同;3种类型欧李果实中,红皮黄肉果实酚类物质的抗氧化能力总体较高,其次为红皮深红肉,红皮浅红肉最低。

LED光质对辣椒果实色泽品质的影响

为探究LED光质处理对辣椒果实色泽的影响,采用光强为140μmol·m^(-2)·s^(-1)的LED蓝光(450 nm)、LED绿光(520 nm)、LED红光(660 nm)和LED白光,其中LED白光为对照,在温度25℃、相对湿度80%和光周期12 h的条件下,对花后30 d的辣椒果实分别进行照射,测定照射前及花后38、46 d辣椒果实的色泽指标、总叶绿素含量、总类胡萝卜素含量、总类黄酮相对含量、总花青素相对含量、β-胡萝卜素含量、叶黄素含量、β-隐黄质含量、玉米黄质含量、辣椒红素含量、美国香料贸易协会标准(ASTA)色值和国际色价标准(ICU)等变化。结果表明,与对照相比,LED红光能加速辣椒果实的转色,花后38和46 d,LED红光照射下辣椒果实的色泽指标均显著优于对照。在花后38 d时,LED红光照射下的辣椒红素含量显著增加至花后30 d的27倍,ASTA色值则显著提高至花后30 d的约3.5倍(P<0.05)。在花后46 d时,LED红光照射下的辣椒红素含量和ASTA色值均显著高于对照(P<0.05)。相比之下,LED绿光和LED蓝光则延缓了辣椒果实正常转色。综上,对位于绿熟前期的辣椒果实采用LED红光照射可以加速其转色,并显著加快辣椒红素积累速率和ASTA色值提高速率(P<0.05)。本研究结果为LED光质加速采前辣椒果实转色,尤其是加快辣椒红素的积累及果实色泽品质提升提供了新思路。

山楂种质资源果实颜色与花青苷含量的关系

测定国家山楂种质资源圃(沈阳)中51份山楂地方品种(Crataegus pinnatifida Bge.var.major N.E.Br.)的花青苷含量,结合果实色差值,以评价山楂果实颜色性状。利用色差仪测定山楂果皮、果肉的色差值(L^(*),a^(*),b^(*))值并计算h°、C^(*)、CIRG值(红色葡萄果实颜色指数);采用酶标仪测定山楂果皮、果肉的花青苷含量;通过相关性分析、主成分分析、聚类分析,明确山楂果实颜色与花青苷含量的关系。结果表明山楂果皮花青苷含量与果皮CIRG值、果肉花青苷含量呈极显著正相关;果肉花青苷含量与果肉a^(*)、C^(*)、CIRG值,及果皮的CIRG值呈极显著正相关。根据果实色差值及花青苷含量可将山楂资源聚为4类:第Ⅰ类果皮a^(*)值较低、花青苷含量最高,果肉a^(*)值与花青苷含量最高;第Ⅱ类果皮a^(*)值最高、花青苷含量较低,果肉a^(*)值与花青苷含量较低;第Ⅲ类果皮a^(*)值呈中等水平、果皮花青苷含量较高,果肉a^(*)值与花青苷含量较高;第Ⅳ类果皮a^(*)值较高、花青苷含量呈中等水平,果肉a^(*)值与花青苷含量呈中等水平。本研究通过对山楂资源果实颜色性状进行数字化赋值,并分析其与花青苷含量之间的关系,为完善山楂种质资源评价提供参考依据。

冠菌素对‘火焰无核’葡萄果实着色及品质的影响

【目的】研究新型植物生长调节剂冠菌素Coronatine(COR)对‘火焰无核’葡萄果实着色及品质的影响,以期筛选出COR的最佳处理浓度,探明COR对葡萄果实着色及品质的影响,为COR的推广应用和葡萄生产提供理论依据和技术参考。【方法】以优良早熟葡萄品种‘火焰无核’葡萄为试材,果实转色初期设置3个COR蘸穗浓度处理,处理后至成熟期分6次采样,对果粒质量、果粒纵横径、果柄耐拉力、硬度、可溶性固形物、总酸、果实色泽、果皮花色苷、叶绿素、胡萝卜素、类胡萝卜素和酚类物质等指标进行连续测定,通过综合分析确定COR的最佳处理浓度。【结果】COR不同浓度处理均可以显著提高果实的单粒质量、可溶性固形物含量,降低总酸含量,提高果实固酸比,提高果皮花色苷含量,降低叶绿素含量,改善果实品质,促进果实着色。其中以COR 2000倍处理的综合品质最佳,与对照相比,可溶性固形物含量提高了8.43%,总酸含量降低了26.19%,固酸比提高了46.31%,花色苷含量提高了1.53倍,叶绿素含量降低了18.18%,a^(*)值提高了1.01倍,CIRG值提高了38.04%,h°值下降了67.13%;COR 3000倍处理促进着色的效果最佳,与对照相比,花色苷含量提高了1.61倍,叶绿素含量降低了27.27%,胡萝卜素降低了20%,a^(*)值提高了1.24倍,CIRG值提高了52.17%,h°值下降了82.78%。【结论】COR不同浓度处理均可提高‘火焰无核’葡萄果实品质,促进果实着色,其中在提高果实品质方面,COR2000倍处理效果最好;在促进果实着色方面,COR 3000倍处理效果最好。

辣椒野生型与果色突变体果实不同发育阶段色泽比较与品质分析

本研究以野生型6421和果色突变体E55为对象,通过测定二者不同发育阶段果实色价、色素含量及品质成分,探讨果实发育过程中色泽和品质成分变化规律。结果表明,从绿熟期至成熟期,6421、E55果色分别由绿转褐再转红和由绿转黄再转橙,二者色价指标a^(*)、C^(*)值增加而色度角(h)值降低,叶绿素(chlorophyll,Chl)含量降低,而类胡萝卜素(carotenoid,Car)含量增加,VC、可溶性糖、可溶性蛋白质以及辣椒素含量增加而纤维素含量下降。对6421、E55果实同一发育阶段色价和品质成分进行比较,绿熟期时,6421与E55果实5个色价指标(L^(*)、a^(*)、b^(*)、C^(*)和h值)、Chl、Car含量以及6个品质指标(纤维素、VC、可溶性糖、可溶性蛋白、辣椒素含量)均无显著差异(P>0.05)。转色期至成熟期,E55果实L^(*)、b^(*)、C^(*)值以及VC、可溶性糖含量均显著高于6421果实(P<0.05),可溶性蛋白质和纤维素含量均显著低于6421果实(P<0.05),辣椒素含量与6421无显著差异(P>0.05)。相关性分析表明,6421和E55果实Chl、Car含量分别与除纤维素含量之外的各品质指标呈显著或极显著负相关、正相关。各品质指标中,纤维素含量与其他指标呈显著或极显著负相关,可溶性糖、可溶性蛋白和辣椒素含量两两之间均呈显著或极显著正相关。本研究可为辣椒果色呈色机理和选育高品质型辣椒奠定理论基础。

多壁碳纳米管对‘夏黑’葡萄果实品质及着色的影响

以九年生‘夏黑’葡萄为试材,采用多壁碳纳米管(MWCNTs)对‘夏黑’葡萄叶面以及果实表面进行喷施的方法,分别设置0 mg·L^(-1)(CK)、4 mg·L^(-1)(M1)、8 mg·L^(-1)(M2)、12 mg·L^(-1)(M3)MWCNTs 4个处理,研究了MWCNTs对‘夏黑’葡萄果实品质的影响,筛选出提高‘夏黑’葡萄果实品质的最佳MWCNTs浓度,以期为纳米材料在葡萄生产中的应用提供参考依据。结果表明:MWCNTs显著提高了葡萄果实质量、纵径。处理后第35天,M1、M2、M3处理的果实色泽指数(CIRG)、固酸比、花色苷含量、苯丙氨酸裂解酶(PAL)及查尔酮异构酶(CHI)活性均高于CK,果皮叶绿素含量及可滴定酸含量低于CK。处理后第35天,M2处理的果实色泽指数、可溶性固形物含量、pH、固酸比、花色苷含量、PAL活性、CHI活性均显著高于CK 7.7%、5.9%、3.8%、26.6%、19.7%、25.22%、16.55%;可滴定酸含量、叶绿素含量分别比CK低16%、16%。综合得分表明M2>M1>M3>CK。对‘夏黑’葡萄喷施8 mg·L^(-1)MWCNTs(M2)对其综合品质提升效果最好。

山楂枸杞复合果汁悬浮和色泽稳定性的研究

为研究黄原胶、羧甲基纤维素钠、海藻酸钠等稳定剂添加量对山楂枸杞复合果汁饮料悬浮稳定性和色泽稳定性的影响,以山楂和枸杞为原料,采用单因素试验和响应面试验方法确定复合稳定剂最佳配方,通过测定在4℃储藏条件下果汁总酸、色泽和VC含量的变化,评估复合稳定剂对果汁稳定性的影响。结果表明,各因素对山楂枸杞复合果汁稳定性影响的顺序为:黄原胶添加量>麦芽糊精添加量>结冷胶添加量>羧甲基纤维素钠添加量。复合稳定剂的最佳配方为0.09%黄原胶、0.22%羧甲基纤维素钠、0.04%结冷胶、0.8%麦芽糊精,此时山楂枸杞复合果汁的稳定性最高,为80.56%。添加稳定剂的果汁在储藏过程中的VC损失和色差变化均比未添加稳定剂的果汁小。复合稳定剂可增加果汁的色泽和悬浮稳定性,提高复合果汁的品质。