新疆红肉苹果杂交二代2个功能型株系果实风味品质的评价

【目的】探讨杂交二代(F2)2个功能型苹果优株及对照品种‘嘎拉’的果实风味品质,旨在为新疆野苹果资源的利用保存及功能型苹果育种理论与技术提供基本资料。【方法】以2个功能型苹果优株‘红心7号’和‘红心9号’为试材,以栽培品种‘嘎拉’为对照,对果实的类黄酮组分、糖酸组分、挥发性成分等风味物质的组成和含量进行检测分析。【结果】‘红心7号’与‘红心9号’硬度、Ca、Fe、Zn和花青苷含量及抗氧化能力均显著或极显著高于‘嘎拉’;3个参试材料均以果糖和苹果酸含量最高,2个功能型苹果优株糖、酸总量均显著高于‘嘎拉’;‘红心9号’果实各类挥发性成分种类数和特征香气成分种类数最高,含量以‘嘎拉’最高,但‘红心7号’各类挥发性成分和特征香气成分的种类数及含量均最低;‘红心9号’与‘红心7号’类黄酮含量分别是‘嘎拉’的3.1倍和2.3倍,但‘红心9号’味感偏酸,而‘红心7号’味感甜酸适口,与‘嘎拉’基本一致。【结论】‘红心7号’硬脆多汁,甜酸适口,果实类黄酮、花青苷和Ca、Fe、Zn含量及抗氧化能力均显著或极显著高于‘嘎拉’。因此,从新疆红肉苹果杂交二代分离群体中能够选育出综合品质优良的功能型苹果新品系。     

不同贮藏处理对‘槜李’果实采后生理特性的影响

本研究以‘槜李’果实为材料,分别进行外源乙烯、减压浸钙和低温贮藏处理,研究各处理条件下‘槜李’果实成熟软化过程中硬度、乙烯释放量、ACS和ACO活性等指标的变化。结果表明:‘槜李’果实软化过程中,硬度逐渐降低,乙烯释放量和ACS活性的峰值同时出现在软化后期;外源乙烯(0.5μl·L^-1)处理后,果实硬度迅速下降,乙烯跃变提前,乙烯释放量增大,ACS活性增强,促进果实迅速软化;用2%CaCl2溶液浸泡处理显著减缓果实软化,降低乙烯释放速率;低温贮藏显著抑制果实硬度下降,表明一定条件的低温贮藏对乙烯释放速率及其相关酶活的控制效果极为显著。     

苹果3个早熟品种果实发育后期硬度及其相关生理指标的初步研究

 以‘泰山早霞’、‘极早红’和‘辽伏’3个早熟苹果品种为试材,研究果实发育期间果实硬度、细胞壁水解酶及淀粉酶活性、乙烯释放量的变化,旨在为探讨果实软化机理提供基本资料,并为早熟苹果品种软化的调控奠定基础。结果表明：① 3个参试品种果实发育过程中果实硬度基本均呈下降趋势,但品种间下降的幅度存在明显差异,其中‘辽伏’花后75 d硬度的下降幅度为35%,‘泰山早霞’50%,‘极早红’53%;② 3个品种果胶甲酯酶（PE）和淀粉酶（Amylase）活性差异不明显,‘泰山早霞’、‘极早红’的多聚半乳糖醛酸酶（PG）、纤维素酶（Cx）活性明显高于‘辽伏’,3个品种PG酶、Cx酶活性变化与其果实硬度变化呈显著负相关;③ 3个参试早熟苹果品种果实发育过程中,乙烯释放量与PG酶、Cx酶活性呈显著正相关。     

‘徐香’与‘海沃德’猕猴桃冷藏期间组织结构与生理变化差异

以猕猴桃‘徐香’（较不耐贮藏）和‘海沃德’（耐贮藏）果实为试材，研究其在0 ℃贮藏期间生理及组织结构的变化差异，从而探究其与耐贮性的关系。结果表明：贮藏期间两品种果肉硬度均不断下将，‘海沃德’果肉硬度降至10 N的时间为150 d，而‘徐香’仅为95 d；‘徐香’的呼吸高峰和乙烯释放高峰的出现分别较‘海沃德’早20 d和10 d，且峰值分别高出16%和250%。贮藏期间‘徐香’果实的质量减少率也显著高于‘海沃德’。在整个贮藏期间，‘海沃德’果实的淀粉、原果胶、纤维素含量均高于‘徐香’，而淀粉酶（AM）、果胶代谢相关酶（多聚半乳糖醛酸酶PG、果胶甲酯酶PE、β–半乳糖苷酶β-Gal）和纤维素酶（Cx）的活性高峰值均低于‘徐香’。‘海沃德’的表皮毛极显著细短于‘徐香’；且角质层厚度及表皮细胞层数都大于‘徐香’；贮藏期间果肉细胞的形变程度‘海沃德’小于‘徐香’；‘海沃德’的细胞壁厚于‘徐香’，且贮藏期间中胶层分裂缓慢，线粒体较完整。总之，耐贮性好的猕猴桃品种角质层和表皮细胞厚，质量减少率较低，呼吸速率和乙烯释放速率慢，细胞壁酶活性低。     

采后‘嘎拉'苹果果实糖和淀粉代谢及关键酶基因表达特性

以‘嘎拉’苹果为试材,研究了采后果实后熟软化过程中可溶性糖和淀粉含量、相关酶活性及关键酶基因表达的变化,分析了低温、乙烯因子(1-MCP、乙烯利)处理对它们的影响,探讨了糖和淀粉代谢与采后‘嘎拉’果实软化的关系。结果表明:‘嘎拉’果实软化的初始阶段,淀粉降解对果实软化的影响最显著,并伴随淀粉酶(AM)活性和MdAM基因表达的快速上升,且淀粉含量、AM活性及它们与硬度的相关性均显著受到低温和乙烯因子的调节,表明淀粉降解与‘嘎拉’果实软化关系密切。糖代谢中,蔗糖、果糖和葡萄糖含量变化与果实软化表现显著的相关性,均受到低温和乙烯因子的调节,但仅有蔗糖磷酸合成酶(SPS)活性与果实硬度的变化显著相关。随着果实软化SPS活性和MdSPS基因的表达量不断增加,并显著受乙烯利的促进,受低温与1-MCP的抑制,其活性及其与硬度间的相关性也受到同样的影响,表明蔗糖代谢参与了‘嘎拉’果实的后熟软化,SPS在蔗糖代谢中起重要作用。     

1-甲基环丙烯和温度对桃和油桃贮藏品质的影响

 以‘秦光2 号’油桃和‘秦王’桃为试材, 在0 ℃和5 ℃两种贮藏温度条件下研究了1-甲基环丙烯(1-MCP) 对果实呼吸速率、乙烯释放速率、硬度、可滴定酸含量、可溶性固形物含量及果肉褐变的影响。结果表明, 0 ℃的贮藏温度能显著降低秦光2号油桃和秦王桃的呼吸速率和乙烯释放速率, 减缓果实软化。1μL·L ^-1的1-MCP 处理能降低果实的呼吸速率和乙烯释放速率, 抑制果实软化, 减少果肉褐变,但对可滴定酸和可溶性固形物含量无明显影响。     

‘大久保’桃常温贮藏过程中香气成分变化及其与乙烯释放的关系

 以‘大久保’桃为材料,研究了果实在采后常温贮藏过程中特征香气及乙烯释放量和相关酶活性的变化。结果表明：果实中“青草型”香气成分含量的降低对风味的影响大于“花香型”香气成分的增加对风味的影响,以“青草型”与“花香型”香气成分的比值为衡量指标,比值最低时风味最佳。乙烯释放量与醛类物质含量和“青草型”香气成分含量呈显著负相关,ACC氧化酶与LOX酶共同调控乙烯的合成,进而调节香气的释放,影响果实的风味。     

苹果果实β-Gal和LOX活性变化特性及其与果实软化的关系

 以‘富士’和‘金冠’苹果果实为试材, 研究了β-半乳糖苷酶(β-Gal) 和脂氧合酶(LOX) 在果实发育、成熟和软化过程中的变化规律及采后乙烯调控对其活性的影响。结果表明: 在果实发育后熟过程中, 金冠果实β-Gal活性显著高于富士, 在果实后熟软化期间这种差异尤为突出; 而富士和金冠果实LOX活性呈相似的变化规律, 虽然花后富士的活性高峰显著高于金冠, 但之后其活性下降迅速,并一直低于金冠。采后苹果果实β-Gal和LOX均受乙烯调控, 乙烯抑制剂1-MCP极显著地抑制β-Gal和LOX的活性, 而乙烯利对二者活性起促进作用, 但因品种耐藏性不同其促进效应不同。综合来看, 苹果果实β-Gal和LOX活性表现相似的变化规律, 并且β-Gal在果实贮藏初期受乙烯的调控作用较LOX显著, 因此认为在苹果果实软化早期β-Gal的作用可能大于LOX。     

番茄果胶裂解酶基因SlPL参与调控裂果机制研究

以裂果率差异极显著的番茄为材料,分析了SlPL(Solyc03g111690)基因的表达差异,进一步利用基因遗传转化对其进行功能验证。结果表明,SlPL在易裂番茄‘NT189’中的表达量显著高于耐裂番茄‘NT91’;在番茄果实中的表达量显著高于根、茎、叶、花等器官,且在果实转色期和红熟期表达量较高;通过灌水处理和ABA处理诱导果实开裂,发现在相同处理时期,易裂果材料果实中SlPL表达量总体显著高于耐裂果材料。通过遗传转化获得SlPL过表达（OEPL）和敲除（pl）的株系,与野生型相比,OEPL更易裂果,且果实硬度显著降低,pl果实硬度升高。OEPL果实中原果胶含量显著低于野生型,水溶性果胶含量显著高于野生型,pl果实中原果胶和总果胶含量显著高于野生型;OEPL果实中果胶裂解酶活性显著高于野生型,pl果实中果胶裂解酶活性显著低于野生型。基因表达分析发现,OEPL果实中细胞壁代谢相关基因SlPG2、SlPME2.1、SlCel2、SlGH9C5和乙烯合成途径相关基因SlACS4、SlACO1的相对表达量显著高于野生型,pl果实中则相反。pl果实中乙烯响应因子SlERF2的相对表达量显著高于...     

乙烯与脂氧合酶在番茄果实香气合成中的作用

通过对番茄成熟突变体和野生型果实香气物质、乙烯释放量、氢过氧化物裂解酶(HPL)、脂氧合酶(LOX)活性及基因表达的测定,明确LOX与乙烯在番茄果实香气物质合成中的作用。以番茄成熟突变体rin、nor、cnr、nr(均为乙烯合成缺陷突变体)、hp-1(高色素突变体,乙烯生成正常)和野生型Ailsa Craig(AC)为试材,分别在果实破色期(0 d)、破色3 d(3 d)和破色7 d(7 d)取果实,测定香气物质、乙烯释放量、LeHPL基因表达、LOX活性和TomloxC基因表达。结果表明,随着果实的成熟,4种乙烯合成突变体果实中的香气物质种类和含量与野生型AC相比均减少,但突变体hp-1果实中香气物质与AC无显著差异;rin、nor、cnr突变体中不产生乙烯,nr中产生少量乙烯,hp-1和AC果实中能正常生成乙烯;除AC果实外,突变体rin、nor、cnr果实中LOX酶活性和TomloxC基因表达水平均较低,而在hp-1和nr破色7 d果实中酶活性和基因表达量均最高;Le HPL表达量在AC和hp-1果实中随果实成熟显著增加,在nor破色7 d显著高于破色期(0 d)和破色3 d的,而在cnr、rin和nr破色7 d均显著下降。在乙烯合成缺陷突变体果实中香气物质种类和含量较野生型减少,且不能合成乙烯或合成少量乙烯,同时LOX酶活性降低,TomloxC及LeHPL表达下降,表明番茄果实香气物质合成的LOX途径是依赖乙烯的过程。     

都市型哈密瓜品种比较试验

本试验以14个哈密瓜品种为试材,记录了其田间长势及果实品质的相关的数据,并进行了分析,以期筛选出适宜在北京种植的白皮白肉和白皮绿肉厚皮甜瓜品种。结果表明:14个参试品种田间长势及果实品质均有显著差异,其中,‘众天7号’的心糖、边糖均为所有品种中最高的,分别为16.5%和13.0%,果实精致、果肉偏厚、口感酥,并且果香浓厚。‘甘甜9号’单果质量最大,可达2.392 kg、肉厚最厚3.8 cm、心糖最高、口感酥脆。综合看来,‘众天7号’和‘甘甜9号’这两个品种可进一步在北京地区推广种植。     

MA贮藏对桑果细胞壁组分和水解酶活性的影响

研究了在(2±1)℃下,MA贮藏对桑果细胞壁组分和水解酶活性的影响,结果表明:MA贮藏可抑制桑果呼吸强度和乙烯释放量,MA贮藏桑果的纤维素酶、果胶甲酯酶和多聚半乳糖醛酸酶等细胞壁水解酶活性和水溶性果胶含量显著低于对照,而果实的纤维素和原果胶含量显著高于对照,从而延缓桑果的软化。     

Effect of calcium dissolved in slightly acidic electrolyzed water on antioxidant system,calcium distribution,and cell wall metabolism of peach in relation to fruit browning

To improve storage of peach fruit, the effect of slightly acidic electrolyzed water (SAEW) dissolved without and with Ca(NO₃)₂ (at concentrations of 0.5, 1, and 2%) on fruit browning, antioxidant system, tissue Ca²⁺ content and distribution, metabolism of cell wall polysaccharides, and related modifying enzymes was evaluated at 25°C for 8 d. Results showed that Ca(NO₃)₂ and SAEW had synergistic effects on reducing ethylene production, respiration rates, and browning index; inhibiting the accumulation of free radicals and lipid peroxidation, and polyphenol oxidase activity; maintaining fruit firmness and higher levels of phenolic compounds, enzymatic and non-enzymatic antioxidants; increasing tissue Ca²⁺ content and distribution; and delaying the disassembly of cell wall polysaccharides and activities of cell wall-modifying enzymes. These results revealed that 1% Ca(NO₃)₂ in SAEW treatment has potential as a commercial cleaning process to extend fruit life, through suppressing browning and solubilization of pectin, protecting the antioxidant system, and facilitating Ca²⁺ absorption.     

嫁接对网纹甜瓜果实中四种特征酯类香气物质含量及其合成相关酶活性的影响

以网纹甜瓜“新汉城翠蜜”为接穗,“圣砧一号”白籽南瓜为砧木,研究嫁接对网纹甜瓜果实中酯类香气物质含量及其合成相关酶活性的影响.结果表明:嫁接降低了网纹甜瓜果实中乙酸乙酯、乙酸己酯、乙酸苯甲酯、乙酸-2-甲基丁酯的含量,在果实完熟时分别较自根网纹甜瓜降低了26.36％、18.52％、13.76％和14.7％.嫁接降低了酯类香气物质合成相关酶-醇脱氢酶(ADH)和醇酰基转移酶(AAT)酶活性,对AAT酶活性影响尤为明显.     

Effect of exogenous putrescine on post-harvest life of strawberry (Fragaria ananassa Duch.) fruit,cultivar Selva

Effect of different concentrations of putrescine on post-harvest life of strawberry (Fragaria ananassa Duch.) fruit, cultivar Selva at 5 °C was studied. Fruits were immerged in 0.3, 0.5, 1 and 2 mM putrescine as well as distilled water (control) for 5 min, then transferred into the fridge (5 °C) together with untreated fruits (dry treatment). The rate of weight loss, ethylene production, flesh firmness, soluble solids content, titratable acidity and pH of fruits were determined 5, 9 and 13 days after the beginning of storage. Flesh firmness, appearance, color change and taste of fruits were also determined in the same intervals using a taste panel. Storage life of the strawberry fruits was significantly increased by the use of putrescine, so that the untreated and control fruits had 6 and 8 days storage life, respectively, while the immerged fruits in 1 and 2 mM putrescine were still suitable to be exposed in the market 12 and 14 days after the beginning of storage, respectively. No significant weight losses were observed in treated fruits compared to controls and dry treatment at all determination times. Ethylene production was decreased significantly by the use of putrescine. Untreated fruits (dry treatment) had the highest rate of ethylene production and the lowest rate was occurred in 2 mM putrescine treatment at all determination times (5, 9 and 13 days after the beginning of storage). The use of putrescine also prevented the softening of fruit flesh during the storage and kept their firmness, so that, the 2 mM putrescine treatment caused the highest fruit firmness at all determination times. Distilled water treatment (control) had the lowest fruit firmness 5 and 9 days after storage, while this occurred for the dry treatment 13 days after storage. Soluble solids content, pH and titratable acidity of the fruits were not significantly affected by the use of putrescine, but the highest and lowest rate of titratable acidity were related to the 2 mM putrescine and dry treatment, respectively, at the three determination times. Overall, the quality of fruits was improved by the use of 2 mM putrescine in terms of properties evaluated by the taste panel.     

梨采后细胞壁成分及果胶酶活性与果肉质地的关系

 以果实质地有明显差异的‘黄花’和‘湘南’梨为试材, 研究了细胞壁组分、钙含量、果实硬度以及果胶代谢酶类活性的变化。结果表明, 两品种上述指标有相同的变化趋势, 但还存在以下差异: 1) 贮藏性差的黄花梨纤维素含量、原果胶含量、果实硬度相对较低, 而果实钙含量、水溶性果胶含量较高; 2) 黄花梨木质素含量较高, 且生成木质素的速率较快; 3) 黄花梨果实的多聚半乳糖醛酸酶(PG) 活性在贮藏前期极显著高于湘南梨果实, 末期两品种差异较小, 而果胶甲酯酶(PME) 活性极显著高于湘南梨。     

子瓜果实贮存期细胞壁超显微结构及相关成分的变化

以大板黑瓜子子瓜为材料,西农8号西瓜为对照,测定和观察不同贮藏期果实硬度、果皮、果肉细胞壁超显微结构、中果皮果胶及其相关酶的变化,研究子瓜果实耐贮性机理。结果表明,贮藏前期子瓜果实硬度较大、中果皮原果胶含量呈上升趋势,25d后平缓下降,西农8号西瓜中果皮果胶酶(PE)、多聚半乳糖醛酸酶(PG)活性在贮藏期存在明显的高峰,子瓜相应酶的活性变化趋势平缓,果皮果肉组织相关细胞结构解离,破坏时期与程度早于、重于子瓜,至实验结束时,已基本丧失其原有的结构,而子瓜还维持一定程度的完整性。由此认为,子瓜贮存期原果胶含量较高,PE、PG活性变化平缓,细胞壁和细胞膜系统超显微结构相对稳定可能与耐贮性有关。     

Effect of low temperatures on pulp browning and endogenous abscisic acid and ethylene concentrations in peach (Prunus persica L.) fruit during post-harvest storage

Summary

Changes in the severity of pulp browning, endogenous abscisic acid (ABA) and ethylene concentrations, and related gene expression in peach (Prunus persica L. ‘Bayuecui’) fruit stored at the biological freezing-point temperature (BFT; 1ºC), at 4ºC, or at room temperature (20ºC; as a control) were investigated.The results showed that fruit stored at room temperature showed climacteric changes in ethylene and ABA concentrations and in levels of expression of the corresponding ethylene synthetase genes (PpACS1, PpACO1) and the gene for a key enzyme of ABA synthesis (PpNCED), concomitant with a significant decrease in fruit firmness and an increase in juice yield. Meanwhile, two sucrose synthase genes (PpSUS1 and PpSUS2) were expressed at relatively low levels. However, fruit firmness decreased slightly and chilling injury (CI) increased significantly 40 d after storage (DAS) at 4ºC, with a significant accumulation of proline [from 8.33 µg g^–1 (at t = 0 d) to 9.125 µg g^–1 (at t = 40 d)]. In contrast, fruit firmness decreased slowly and pulp browning increased slightly 80 DAS at the BFT ( 1ºC), with a lower accumulation of proline than in fruit stored at 4ºC. The concentrations of soluble sugars and titratable acidity decreased during storage at 1ºC, 4ºC, or 20ºC, but there was a peak of soluble sugars at a late stage of storage at the BFT ( 1ºC). The fruit browning index was significantly and positively correlated (R ² = 0.967) with ABA concentration. The decrease in ABA concentration in cold-stored fruit (at both 1ºC and 4ºC) inhibited ethylene production. Moreover, there was no significant correlation between CI in fruit and ethylene production. In conclusion, the decrease in ABA concentration reduced ethylene concentrations and inhibited the development of pulp browning, which resulted in an improved taste, but crisper fruit, when fruit were stored at the BFT (–1ºC).     

The effects of storage temperature and fruit size on firmness,extractable juice,woolliness and browning in two nectarine cultivars

Fruit firmness, extractable juice, woolliness and browning of the mesocarp tissue in ‘Independence’ and ‘Flavortop’ nectarines stored at —0.5°, 3°, 5° and 7°C for four weeks were determined during ripening at 15°C. The firmness of both ‘Independence’ and ‘Flavortop’ during ripening decreased as storage temperatures increased. The percentage extractable juice after cold storage and during ripening varied considerably between cultivars and between the storage temperatures. The extractable juice of fruit stored at higher temperatures tended to increase during ripening, whereas fruit stored at lower temperatures tended to decrease first before increasing. At storage temperatures of —0.5° and 3°C both cultivars passed through a stage of woolliness during ripening, while less woolliness occurred after storage at 5° and 7°C. In both cultivars the percentage extractable juice during ripening was higher on average at storage temperatures of 5° and 7°C. Severe browning of mesocarp tissue in both cultivars occurred during ripening after storage at 3°C. The effect of fruit size on changes in firmness, development of woolliness and mesocarp browning in ‘Flavortop’ nectarines stored at — 0.5°C for four weeks and ripened at 15°C was also determined. Larger nectarines lost firmness more rapidly, woolliness occurred sooner and the mesocarp tissue was more prone to browning than smaller fruit during ripening.     

猕猴桃PG基因在果实贮藏过程中的表达及其与硬度的关系

为鉴定猕猴桃果实贮藏过程中参与果胶降解的关键酶多聚半乳糖醛酸酶（PG）基因,以‘徐香’猕猴桃为试材,利用转录组测序（RNA-seq）和实时荧光定量（qRT-PCR）技术,研究了猕猴桃PG基因在不同成熟进程及外源乙烯诱导后果实中的表达变化。根据RNA-seq结果,可以将37个PG基因在采后不同时期的表达趋势分为4类,Achn325011、Achn240441、Achn071601和Achn100411,分别在采后2、4、6和8 d有表达高峰。鉴于果实硬度在常温贮藏6 d较4 d时急剧下降,因此利用qRT-PCR重点验证了其中的2类14个基因,发现4个基因在采后2 d和4 d明显上调,与果实硬度在6 d时的下降相关。进一步利用外源乙烯处理果实,发现其中1个基因Achn071601在处理与对照果实中的差异表达与同时期果实硬度的变化趋势一致,是猕猴桃关键的PG基因。