特色果蔬的贮运保鲜技术取得突破

近日，广东省科技厅主持召开了由中国科学院华南植物园等单位完成的“南方特色果蔬的贮运保鲜机制与关键技术”成果鉴定会。 该项目成果由华南植物园果蔬采后生物学研究组牵头，联合华南农业大学、广州市农业科学研究院科相关科研人员历时5年完成。项目在南方特色果蔬采后衰老和品质劣变机制研究方面，揭示了生物大分子氧化在衰老和果实质地劣变中的作用；明确了NO信号分子在调控果实衰老和劣变中的作用机理；阐明了能量亏损引发果实衰老和褐变的机制；明确了果蔬在不同贮藏条件下品质变化规律和生理应答机制。发明了柑橘酸腐病控制和带叶保鲜、荔枝无硫防褐变防腐综合保鲜、蔬菜衰老和冷害控制、葡萄无硫综合保鲜等特色果蔬安全保鲜新技术；研发了新的植物源防腐保鲜剂及其配套应用技术，显著减少了柑橘、荔枝、杨梅、葡萄、番木瓜、菜心、黄秋葵等特色果蔬采后损失，减少化学杀菌剂使用，保持了果蔬的品质与安全。     

番茄果实采后一氧化氮处理对活性氧代谢的影响

 以番茄品种‘百利’为试材, 研究了NO处理对其采后活性氧代谢的影响。结果表明: NO处理可推迟果实呼吸和乙烯高峰的出现, 抑制O·₂ 和H₂O₂ 的累积, 保持了贮藏后期SOD、CAT、POD、APX 较高的活性以及GSH和AsA含量的较高水平, 延缓了MDA含量和膜相对透性的升高, 降低膜脂过氧化程度, 延缓了果实衰老。     

乙烯调控非跃变型果实成熟衰老研究进展

 非跃变型果实成熟衰老过程产生的乙烯远低于跃变型果实,20世纪70年代以来,乙烯被认为在非跃变型果实成熟衰老中发挥的作用非常有限。然而,由于该类型包含许多重要经济价值的果实,如柑橘、草莓、葡萄、枇杷等,近年来乙烯参与非跃变型果实成熟衰老相关研究陆续有报道。大量结果明确表明,非跃变型果实诸多成熟相关过程也直接受乙烯调控,且非跃变型果实和跃变型果实品质变化的某些分子调控途径非常相似。本文中主要综述了乙烯调控非跃变型果实成熟衰老研究进展。     

一氧化氮对猕猴桃果实营养品质和活性氧代谢的影响

分别用10、20和30μL.L-1一氧化氮(NO)气体熏蒸猕猴桃果实,研究NO对采后徐香猕猴桃(Actinidia chi-nensis Planch.cv.Xuxiang)的营养品质变化和活性氧代谢的影响。结果表明,20μL.L-1 NO处理后的猕猴桃果实含有较低的可溶性固形物和较高的可滴定酸、维生素C,且果实中丙二醛和超氧自由基质量分数低于其他体积分数的NO熏蒸处理(10和30μL.L-1 NO)。20μL.L-1 NO处理降低了猕猴桃果实中LOX活性,延缓了猕猴桃果实采后期间CAT活性的降低,显著提高了猕猴桃果实SOD和POD活性,且显著降低了猕猴桃果实中过氧化氢的质量分数。20μL.L-1 NO气体熏蒸保持了猕猴桃中较高的叶绿素、类胡萝卜素以及维生素E的质量分数。     

外源硝酸铵对厚皮甜瓜坐果节位叶片衰老及果实产量和品质的影响

以厚皮甜瓜品种"迎春(F1)"为试材,研究了叶面喷施不同浓度硝酸铵(NH4NO3)对坐果节位叶片衰老及果实产量和品质的影响。结果表明:叶面喷施1.0、3.0、5.0 g·L-1的硝酸铵可不同程度地增加坐果节位叶片的叶绿素和可溶性蛋白质的含量,提高光合电子传递速率(ETR)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光化学量子效率(Y(Ⅱ)),降低初始荧光参数(Fo),减缓MDA含量的增长,增加果实的可溶性固形物、可溶性糖和维生素C含量,但对单果质量影响不显著。表明叶面喷施3.0 g·L-1外源硝酸铵,对延缓厚皮甜瓜坐果节位叶片衰老,提高厚皮甜瓜果实品质的效果最佳。     

脱落酸在桃果实成熟过程中的作用

 以白凤桃为试材,分析研究了桃果实生长发育过程中脱落酸（ABA）的变化以及外源ABA和氟啶酮（Fluridone）处理对果实发育后期离体果实后熟衰老进程的影响,探讨了ABA与桃果实成熟的关系。结果表明：桃果实生长发育后期果实内源ABA的积累构成了果实成熟的启动信号,而ABA高峰的出现启动了果实的后熟衰老进程;外源ABA处理促进了采后果实的后熟衰老进程,而Fluridone处理抑制了果实内源ABA的生物合成和乙烯产生,延缓了桃果实的后熟软化;乙烯则可能作为ABA的一种辅助因子影响果实的后熟衰老进程。     

脂氧合酶与果实的成熟衰老——文献综述

概述了高等植物中的脂肪酸氧化的脂氧合酶（ＬＯＸ）途径;ＬＯＸ与乙烯、茉莉酸、脱落酸和果实成熟衰老的关系;ＬＯＸ基因及其在果实成熟衰老进程中的表达模式等。对ＬＯＸ在果实成熟衰老过程中的可能作用机理进行了讨论。     

1-甲基环丙烯延缓果实衰老作用机制研究综述

 综述了1-甲基环丙烯(1-MCP)延迟果实衰老的作用效果和作用机理。1-MCP是一种乙烯作用抑制剂，可以延缓采后果实衰老，提高果实的贮藏品质和货架寿命，调节果实衰老相关基因的表达和酶的活性，并对果实风味和采后病害有一定影响。     

桃果实采后脂氧合酶活性与内源乙烯对果实软化衰老的影响

以“南京白凤”桃果实为试验材料，研究了常温、低温和GA3处理条件下果实采后LOX(脂氧合酶)活性变化和内源乙烯发生规律。获得了后熟期间LOX活性与乙烯发生量的跃变型变化趋势；在果实软化衰老过程中，LOX启动膜脂过氧化作用导致果实软化衰老，同时内源乙烯的大量合成加速了果实的软化衰老速度；低温和GA3处理通过降低LOX活性和抑制内源乙烯合成，并延迟其高峰期的出现而延缓果实衰老进度。     

一氧化氮对冷藏过程中‘肥城桃’果实内挥发性物质的影响

【目的】探讨一氧化氮(NO)对冷藏过程中‘肥城桃’果实内挥发性物质生物合成的影响。【方法】将生理成熟期的‘肥城桃’果实用不同浓度NO气体熏蒸3 h,考察冷藏过程中桃果实内醇类、醛类和酯类物质的释放量及其相关酶的活性。【结果】冷藏过程中,‘肥城桃’果实内醇类和醛类物质总量基本呈下降趋势,而酯类总量呈上升趋势。与对照相比,NO处理延缓了‘肥城桃’果实中醇类、醛类物质总量的下降和酯类物质总量的增加,10μL·L-1NO处理比5μL·L-1NO处理效果更明显。NO处理使桃果实中醇酰基转移酶(AAT)、乙醇脱氢酶(ADH)和脂氧合酶(LOX)的活性受到抑制。【结论】NO参与桃果实中一些挥发性物质的合成,NO处理能较好地保持冷藏果实挥发性物质的含量,维持果实良好的贮藏品质。     

一氧化氮对草莓果实衰老的影响

 以硝普钠( SNP) 为一氧化氮供体, 研究不同浓度的SNP对‘丰香’草莓果实软化过程相关酶活性的影响。结果表明, 5 μmol·L ^{- 1} SNP可以显著增强果实CAT活性, 抑制PME、纤维素酶、PPO和LOX活性, 并推迟了PPO和LOX活性高峰的出现。但对exo-PG酶活性作用不明显。揭示了适宜浓度的一氧化氮通过改变果实软化酶的活性, 能够抑制果实衰老的规律, 证明了一氧化氮对果实衰老的影响具有双重生物效应。     

‘乔纳金’苹果采后1-MCP 处理对常温贮藏效果的影响

 试验结果表明, 1-MCP (1 - 甲基环丙烯) 处理可以明显降低‘乔纳金’苹果果实的呼吸强度,延迟呼吸高峰的出现, 明显减缓硬度和酸度的下降, 减少叶绿素的分解, 但低浓度的1-MCP 处理增加了苦痘病的发生率。     

Historical variation in the mineral composition of edible horticultural products

Summary

Historical variation in the mineral composition of edible horticultural products was determined from UK and USA food survey data. From these data, it was possible to measure the variation in the mineral composition of edible horticultural products in general, and in edible horticultural products grouped as vegetables, fruits or nuts, in the 1930s and in the 1980s (or later) for both countries. Thus, the hypothesis that the mineral composition of edible horticultural products had altered since the 1930s was tested. The average concentrations of Cu, Mg and Na in the dry matter of vegetables, and the average concentrations of Cu, Fe and K in fruits decreased significantly between the 1930s and the 1980s in the UK. The same hypothesis was tested with comparable data from the USA, whose historical horticultural and consumer practices have paralleled those of the UK. Data from the USA showed that the average Ca, Cu and Fe concentrations in the dry matter of vegetables, and the average concentrations of Cu, Fe and K in fruits had decreased significantly since the 1930s. There were insufficient data to determine if the mineral composition of any single edible horticultural species had altered significantly over time either in the UK or in the USA. The nutritional implications of this study are discussed. Since horticultural products in general, and fruits and nuts in particular, are relatively small contributors of minerals to the average UK diet, historical changes in mineral composition are unlikely to be significant in overall dietary terms.     

从28届国际园艺学大会看果蔬园艺产品营养学研究现状

 有关果蔬等园艺产品的营养与生物活性物质的研究是近年园艺学研究的热点问题之一。主要根据28届国际园艺学大会论文摘要,对当前国内外有关水果、蔬菜的营养和生物活性物质的研究情况进行全面系统的总结,当前果蔬园艺产品营养学的研究包括栽培品种与野生资源,主要研究内容涉及果蔬中营养和生物活性物质的含量、分布、影响因子及其调控措施以及对人体的功效等;对有关的技术方法和存在的问题也进行了介绍,旨在为今后研究提供参考。     

一氧化氮熏蒸处理对双孢蘑菇采后褐变及衰老的影响

以双孢蘑菇为试材,研究了在(10±0.5)℃条件下,不同浓度一氧化氮(NO) (30、60、90 μL/L)气体熏蒸处理对双孢蘑菇贮藏过程中感官品质、褐变度、多酚氧化酶(PPO)和过氧化物酶(POD)活性的影响.结果表明:外源NO熏蒸处理显著抑制了PPO活性的升高(8.90％～33.13％),减轻贮藏期的褐变程度.提高了贮藏后期POD活性(12.28％～76.27％),延缓了双孢蘑菇的衰老,有效延长了货架期(2 d).其中,NO浓度为60 μL/L时效果最好.     

Role of SIRT1/eNOS/NO signaling pathway in protective effect of ginsenoside Rb1 against replicative senescence of endothelial cells

AIM: To explore the effect of ginsenoside Rb1 on replicative senescence of endothelial cells and the role of SIRT1/eNOS/NO signaling pathway in this process. METHODS: The replicative senescence model of primary human umbilical vein endothelial cells (HUVECs) was established. The morphological change of the cells, the proportion of senescence-associated β-galactosidase (SA-β-Gal) positive cells and the plasminogen activator inhibitor 1 (PAI-1) expression were detected to assess the senescence model. The expression of eNOS and PAI-1 at mRNA and protein levels in the aging cells was determined by real-time PCR and Western blot before and after silencing of SIRT1 was performed. The NO concentration in the cell culture supernatant was measured by nitrate reductase assay. RESULTS: HUVECs with cumulative population-doubling level (CPDL) at 16 were chosen as the replicative senescence model in this research. Ginsenoside Rb1 at 80 μmol/L significantly reduced the expression of PAI-1 at mRNA and protein levels. Furthermore, ginsenoside Rb1 increased the expression of SIRT1 and eNOS at mRNA and protein levels, and increased the NO content. SIRT1 silencing inhibited the expression of eNOS at mRNA and protein levels and reduced NO generation, leading to an increase in the expression of PAI-1 at mRNA and protein levels. Upon intervention of ginsenoside Rb1, the eNOS and PAI-1 expression and the level of NO were not reversed. CONCLUSION: Ginsenoside Rb1 modulates SIRT1/eNOS/NO signaling pathway to prevent the replicative senescence of HUVECs.     

Crude Polysaccharide and Triterpene Content of Ganoderma Fruit Bodies at Different Stages of Development

Crude polysaccharide and triterpene levels were determined in the fruit bodies of eleven Lingzhi samples,designated as Ganoderma lucidum,G.capense and G.tsugae,harvested at four different stages of development: budding,elongation,maturation and senescence.In most cases,crude polysaccharide levels were highest at the budding stage,decreased during the elongation stage,increased again at maturation and were lowest at senescence.Triterpene levels generally remained relatively high during the first three develo...     

Insulin protects endothelial progenitor cells against functional damage caused by high glucose

AIM: To investigate the impact of various levels of glucose on endothelial progenitor cells (EPCs) proliferation, senescence, and nitric oxide (NO) secretion,and the effect of insulin under high glucose conditions.METHODS: Mononuclear cells were collected from rat bone marrow by density gradient centrifugation, cultured with medium 199, and identified to be EPCs at 7th day by flk-1 and AC133 double staining. EPCss were harvested and incubated with glucose (5, 10, 20, 40 mmol/L) or insulin (0.1, 1, 10, 100 nmol/L) under high glucose conditions for 24 h or 7 days. Proliferative capacity, senescence level and NO secretion (after 24 h of incubation) were subsequently determined.RESULTS: High glucose (40 mmol/L) markedly inhibited EPCs proliferation, accelerated EPCs senescence, and decreased NO production (all P<0.05). Compared with high glucose (40 mmol/L) group, insulin intervention promoted EPCs proliferation, inhibited EPCs senescence (prominent at 1 nmol/L, P<0.05), and enhanced NO secretion (prominent at 10 nmol/L, P<0.05).CONCLUSION: High glucose harms EPCs proliferation and function, while insulin alleviates this jeopardy, indicating the protective role of insulin for the cardiovascular system.     

Horticultural science-a century of discovery and application

The Journal of Horticultural Science and Biotechnology (JHSB) celebrates, in 2019, a century of continuously publishing peer-review, research-based articles and reviews. Since 1919 scientific discoveries and their application through subsequently-evolved industrial technologies have formed the basis for enormous advances and changes in the production of fruit, vegetables and ornamentals. New industries have been founded and expanded. Science has brought greater precision, predictability and reliability into horticultural crop production, raising the quality and range of products Market forces themselves have imposed vast change in the manner by which horticultural products are produced. Horticultural industries have coped with and thrived on these changes because of their swift and effective adoption of discoveries in horticultural science, which in turn has driven the need for more research in a cyclic process. This review follows, through a selection of articles published in JHSB, the evolution of aspects of horticultural science and identifies how change has influenced crops and their production. The history of change in horticultural science and the industries which it serves is contained within the articles selected. They demonstrate the successful manner in which JHSB has fulfilled the aspirations of its founders for a science-based journal which offers new ideas for industry.